For class I'm turning an aluminum flywheel. 3" diameter. The steps
a face the sides, drill & ream the center, press onto a mandrel, turn
the outside and sides. Anyway, after pressing it onto the mandrel (yes,
I cleaned out the cutting oil) I've found that I have to go very slowly
or the cutting tool will grab the wheel and spin it on the mandrel.
What are some good ways to deal with this problem? I already crammed
it as far onto the mandrel as I'm comfortable with. I'm tempted to just
loctite the damn thing.

--
B.B. --I am not a goat! thegoat4 at airmail dot net
http://web2.airmail.net/thegoat4/

"B.B." u wrote in message
news
For class I'm turning an aluminum flywheel. 3" diameter. The steps
a face the sides, drill & ream the center, press onto a mandrel, turn
the outside and sides. Anyway, after pressing it onto the mandrel (yes,
I cleaned out the cutting oil) I've found that I have to go very slowly
or the cutting tool will grab the wheel and spin it on the mandrel.
What are some good ways to deal with this problem? I already crammed
it as far onto the mandrel as I'm comfortable with. I'm tempted to just
loctite the damn thing.



Wow!

Without seeing it, it's hard to second guess the problem. Can I assume the
mandrel is ½?" Pressed with an arbor press? Tapped in with a hammer? Cast
aluminum, or bar stock?

That's not much to drive a large diameter cut. A couple things can help.
Make certain that your cutting tool is sharp, with a slight radius (1/64"
max) stoned on the tip so it cuts smoothly, but not too large, so you
increase surface area in contact with the cut. That can lead to chatter, and
increases cutting pressure, often overwhelming the friction fit of the
mandrel. A little positive rake will lower cutting resistance, but too
much will encourage hogging or chatter, so you have to walk a delicate line.
Take a lighter cut and finer feed. Do what it takes to lower cutting
pressure, but don't allow chatter to start. Once you get it, it can be
difficult to eliminate. Higher speeds encourage chatter, but improve
machining.

Harold

"B.B." u wrote in message
news
For class I'm turning an aluminum flywheel. 3" diameter. The steps
a face the sides, drill & ream the center, press onto a mandrel, turn
the outside and sides. Anyway, after pressing it onto the mandrel (yes,
I cleaned out the cutting oil) I've found that I have to go very slowly
or the cutting tool will grab the wheel and spin it on the mandrel.
What are some good ways to deal with this problem? I already crammed
it as far onto the mandrel as I'm comfortable with. I'm tempted to just
loctite the damn thing.


Heat it, then quickly press it on--to remove, heat it up again.......~350
degrees F. should do the trick....remember, aluminum expands at a greater
rate than steel....

Oh, and take lighter cuts, use a sharp tool, etc....cause if it heats
up........

--

SVL

On Wed, 02 Mar 2005 22:25:40 -0600, "B.B."
u wrote:

For class I'm turning an aluminum flywheel. 3" diameter. The steps
a face the sides, drill & ream the center, press onto a mandrel, turn
the outside and sides. Anyway, after pressing it onto the mandrel (yes,
I cleaned out the cutting oil) I've found that I have to go very slowly
or the cutting tool will grab the wheel and spin it on the mandrel.
What are some good ways to deal with this problem? I already crammed
it as far onto the mandrel as I'm comfortable with. I'm tempted to just
loctite the damn thing.

Superglue works quite well as long as you dont have any tool chatter.
So does regular fingernail polish.

I make my own mandrels by turning a rod to diameter, drilling and
tapping the end, then slitting with a hacksaw or slitting saw. Slip
over the workpiece, then installing a socket head cap screw in the
tapped hole to expand as needed.

Best if done in a collet of course. but works fine in a three jaw if
you dont remove it during any of the process.

Cheap and easy to make, grabs well.

Gunner


Lathe Dementia. Recognized as one of the major sub-strains of the
all-consuming virus, Packratitis. Usual symptoms easily recognized
and normally is contracted for life. Can be very contagious.
michael

"Gunner" wrote in message
news
On Wed, 02 Mar 2005 22:25:40 -0600, "B.B."
u wrote:

For class I'm turning an aluminum flywheel. 3" diameter. The steps
a face the sides, drill & ream the center, press onto a mandrel, turn
the outside and sides. Anyway, after pressing it onto the mandrel (yes,
I cleaned out the cutting oil) I've found that I have to go very slowly
or the cutting tool will grab the wheel and spin it on the mandrel.
What are some good ways to deal with this problem? I already crammed
it as far onto the mandrel as I'm comfortable with. I'm tempted to just
loctite the damn thing.

Superglue works quite well as long as you dont have any tool chatter.
So does regular fingernail polish.

I make my own mandrels by turning a rod to diameter, drilling and
tapping the end, then slitting with a hacksaw or slitting saw. Slip
over the workpiece, then installing a socket head cap screw in the
tapped hole to expand as needed.

Best if done in a collet of course. but works fine in a three jaw if
you dont remove it during any of the process.

Cheap and easy to make, grabs well.

Gunner

Works real well with a pipe plug, too. It's a good idea to try to make
your cuts at 90°, so when you expand the mandrel it does so uniformly and
retains concentricity. Rough turn, drill, tap, split, deburr the threads
with your pipe tap, then finish turn with the pipe plug tightened ever so
slightly. You can do surprisingly precise work with a mandrel so made.

Harold

"Harold and Susan Vordos" wrote in message
...

"Gunner" wrote in message
news
On Wed, 02 Mar 2005 22:25:40 -0600, "B.B."
u wrote:

For class I'm turning an aluminum flywheel. 3" diameter. The steps
a face the sides, drill & ream the center, press onto a mandrel,
turn
the outside and sides. Anyway, after pressing it onto the mandrel
(yes,
I cleaned out the cutting oil) I've found that I have to go very slowly
or the cutting tool will grab the wheel and spin it on the mandrel.
What are some good ways to deal with this problem? I already
crammed
it as far onto the mandrel as I'm comfortable with. I'm tempted to
just
loctite the damn thing.

Superglue works quite well as long as you dont have any tool chatter.
So does regular fingernail polish.

I make my own mandrels by turning a rod to diameter, drilling and
tapping the end, then slitting with a hacksaw or slitting saw. Slip
over the workpiece, then installing a socket head cap screw in the
tapped hole to expand as needed.

Best if done in a collet of course. but works fine in a three jaw if
you dont remove it during any of the process.

Cheap and easy to make, grabs well.

Gunner

Works real well with a pipe plug, too. It's a good idea to try to make
your cuts at 90°, so when you expand the mandrel it does so uniformly and
retains concentricity. Rough turn, drill, tap, split, deburr the threads
with your pipe tap, then finish turn with the pipe plug tightened ever so
slightly. You can do surprisingly precise work with a mandrel so made.


The "splitting" part is what becomes the problem here--it's best done in
this case with just a plain ole hacksaw....with the mandrel still firmly
chucked in the lathe....

From start to finish, once you chuck your mandrel blank you should forget
that you even *own* a chuck key--throw the darned thing out the bay door and
retrieve it later......cause if you unchuck the work and have to re-set it
then all bets are off....

===

Never forget that turning or milling, makes no differance--your primary axis
is always gonna defined by your spindle bearings, and all other planes are
defined from that referance.

--

SVL

On Thu, 3 Mar 2005 00:56:06 -0800, "Harold and Susan Vordos"
wrote:


"Gunner" wrote in message
news
On Wed, 02 Mar 2005 22:25:40 -0600, "B.B."
u wrote:

For class I'm turning an aluminum flywheel. 3" diameter. The steps
a face the sides, drill & ream the center, press onto a mandrel, turn
the outside and sides. Anyway, after pressing it onto the mandrel (yes,
I cleaned out the cutting oil) I've found that I have to go very slowly
or the cutting tool will grab the wheel and spin it on the mandrel.
What are some good ways to deal with this problem? I already crammed
it as far onto the mandrel as I'm comfortable with. I'm tempted to just
loctite the damn thing.

Superglue works quite well as long as you dont have any tool chatter.
So does regular fingernail polish.

I make my own mandrels by turning a rod to diameter, drilling and
tapping the end, then slitting with a hacksaw or slitting saw. Slip
over the workpiece, then installing a socket head cap screw in the
tapped hole to expand as needed.

Best if done in a collet of course. but works fine in a three jaw if
you dont remove it during any of the process.

Cheap and easy to make, grabs well.

Gunner

Works real well with a pipe plug, too. It's a good idea to try to make
your cuts at 90°, so when you expand the mandrel it does so uniformly and
retains concentricity. Rough turn, drill, tap, split, deburr the threads
with your pipe tap, then finish turn with the pipe plug tightened ever so
slightly. You can do surprisingly precise work with a mandrel so made.

Harold

Ayup. Mine are threaded for 1/8" pipe plugs..but most folks dont have
em, so suggested the standard bolt. The threaded and Tapered pipe
thread is the best way to go.

I slit mine on the Mastermill with slitting saws and the mandrels held
in a 5C indexer.

Sometimes I have to think hard on how to do things when the other guy
may not have Stuff.

Gunner


Lathe Dementia. Recognized as one of the major sub-strains of the
all-consuming virus, Packratitis. Usual symptoms easily recognized
and normally is contracted for life. Can be very contagious.
michael

In article ,
"PrecisionMachinisT" wrote:

The "splitting" part is what becomes the problem here--it's best done in
this case with just a plain ole hacksaw....with the mandrel still firmly
chucked in the lathe....

From start to finish, once you chuck your mandrel blank you should forget
that you even *own* a chuck key--throw the darned thing out the bay door and
retrieve it later......cause if you unchuck the work and have to re-set it
then all bets are off....

Nothing says the chuck has to remain on the lathe, just the mandrel
stays in the chuck.

--
Free men own guns, slaves don't
www.geocities.com/CapitolHill/5357/

In article , B.B.
says...

For class I'm turning an aluminum flywheel. 3" diameter. The steps
a face the sides, drill & ream the center, press onto a mandrel, turn
the outside and sides. Anyway, after pressing it onto the mandrel (yes,
I cleaned out the cutting oil) I've found that I have to go very slowly
or the cutting tool will grab the wheel and spin it on the mandrel.

Change the order in which you perform the operations.

1) clamp via the OD on the rough blank, and turn one side and the
part of the OD that is extending out from the chuck jaws, but leave
20 thou or so for cleanup later on the OD.

2) in the same setup, rough drill the bore.

3) Flip it around in the chuck, so that the jaws are now grabbing
on the finished OD from the previous step. Profile the second side
and the OD again to a 20 over size. Finish bore and ream the
ID dimension. (when you seat the part for this step, be sure
it is bottomed in the jaws and that there are no chips under
it)

4) use a stub mandrel in the headstock, with the stub turned
in place - at a diameter one thou under the bore size.
Also put a pusher block in the tailstock, a live center makes
this run easily.

Then your flywheel goes over the stub on the mandrel (which picks
up the finished bore) and the pusher block forces the part up against
the face of the mandrel, which now drives the part for taking the
final OD cut on the part.

You can glue some sandpaper on the mandrel face (which should be
only slightly smaller then the part's diameter) to assist with
driving it.

The benefit of this approach is:

The OD of the part is dead concentric with the bore, which is
the most important issue.

The OD is turned with the part held rigidly between two large
driver blocks - so there is much less chance for ringing or
chatter.

You can take as big a cut on the OD as you want because it
*will* drive.

How do I know all this? Because I spent a few years making
crane sheaves out of nylon. This is the way it was done, and
the OD cuts were often done with form tools, which require
large cutting forces and are very prone to chatter becaue of
the amount of tool engaged in the workpiece.

Make a stub mandrel and a pusher block, you could turn 20 flywheels
from blanks in a half hour.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

hold the mandrel short so the flywheel is touching the jaws and center
drill a piece of 1 x 1 x 4 in the center of the length and use the
tailstock to press the flywheel up against the jaws .......

or

just turn it backwards and turn your tool upside down, so the nut will
tend to tighten instead of loosen

"Nick Hull" wrote in message
...
In article ,
"PrecisionMachinisT" wrote:

The "splitting" part is what becomes the problem here--it's best done
in
this case with just a plain ole hacksaw....with the mandrel still firmly
chucked in the lathe....

From start to finish, once you chuck your mandrel blank you should
forget
that you even *own* a chuck key--throw the darned thing out the bay door
and
retrieve it later......cause if you unchuck the work and have to re-set
it
then all bets are off....

Nothing says the chuck has to remain on the lathe, just the mandrel
stays in the chuck.


While most mounts are pretty darned accurate, I wouldnt bet on it without
having some familarity with the actual lathe thats being used.

--

SVL

"PrecisionMachinisT" wrote in message
...

"Nick Hull" wrote in message
...
In article ,
"PrecisionMachinisT" wrote:

The "splitting" part is what becomes the problem here--it's best done
in
this case with just a plain ole hacksaw....with the mandrel still
firmly
chucked in the lathe....

From start to finish, once you chuck your mandrel blank you should
forget
that you even *own* a chuck key--throw the darned thing out the bay
door
and
retrieve it later......cause if you unchuck the work and have to
re-set
it
then all bets are off....

Nothing says the chuck has to remain on the lathe, just the mandrel
stays in the chuck.


While most mounts are pretty darned accurate, I wouldnt bet on it without
having some familarity with the actual lathe thats being used.


Agreed!

While the error is usually minor, even with a D type spindle, orientation
affects concentricity in many instances. Many of the D type spindles have
a witness mark for that reason.

Harold

In article
,
"B.B." u wrote:

For class I'm turning an aluminum flywheel. 3" diameter. The steps
a face the sides, drill & ream the center, press onto a mandrel, turn
the outside and sides. Anyway, after pressing it onto the mandrel (yes,
I cleaned out the cutting oil) I've found that I have to go very slowly
or the cutting tool will grab the wheel and spin it on the mandrel.
What are some good ways to deal with this problem? I already crammed
it as far onto the mandrel as I'm comfortable with. I'm tempted to just
loctite the damn thing.

Replying to all:

I like the method jim described since it's sturdy, but I can't use it
since I've already done just about all of it except for turning the
grooves in the sides. Of course, if I ruin it.... However, I believe
we're doing this part mostly for the sake of turning something between
centers as part of the class. I'm nearly done with the assigned project
and have a half a semester to go for whatever, so I can probably try
this at some point.
Harold, When you wrote "Can I assume the mandrel is ½?" that last
character came out as Pi on my screen, and I have no idea what you meant
by it. But, bar stock, pressed the mandrel in with an arbor press.
We're using general-purpose indexable carbide tools on all of the
lathes, but I have a fresh bit of tool steel and I'll see about making
my own tool to play with. I did find (counter-intuitively) that running
on the high side of the cutting speeds helped.
I'll likely settle on the heat & press method suggested by
PrecisionMachinist. Class is on monday--I'll let you know how it goes.

--
B.B. --I am not a goat! thegoat4 at airmail dot net
http://web2.airmail.net/thegoat4/

In article ,
B.B. u wrote:

[ ... ]

Harold, When you wrote "Can I assume the mandrel is ½?" that last
character came out as Pi on my screen, and I have no idea what you meant
by it.

It comes out as "1/2" on some screens, but since it is a part of
the extended ASCII character set, there are no promises that it will
show up the same on all. This is a primary reason for sticking to only
the characters which show on the tops of your keyboard keys. Anything
which requires fancy keyboard tricks to generate (e.g. Compose-1-2 on my
Sun keyboard) will not mean the same to everybody in this newsgroup with
mixed systems in mixed locations around the world. (And it even chances
on some of them when you change the characterset used by the program.

But, bar stock, pressed the mandrel in with an arbor press.

Hmm ... bar stock? Not turned to have a very slight taper?
That could be part of the problem. I think that the typical taper on an
arbor for turning between centers is 0.001 inch/foot, but I'm sure that
Harold will correct me if I am wrong.

We're using general-purpose indexable carbide tools on all of the
lathes, but I have a fresh bit of tool steel and I'll see about making
my own tool to play with.

That could help, as typically a carbide insert is not as sharp
as a frechly ground and honed HSS bit.

Note that I have some very nice sharp solid carbide inserts
(1/4" IC 55 degree diamond *without* TiN coating or the like, which I
use when I want a sharp tool but am too lazy to grind my own. :-)

I did find (counter-intuitively) that running
on the high side of the cutting speeds helped.
I'll likely settle on the heat & press method suggested by
PrecisionMachinist. Class is on monday--I'll let you know how it goes.

If your arbors *do* have a taper, it should get it that much
tighter. (Also note that the heat generated by turning could expand the
aluminum and loosen the grip on the steel arbor, which would make the
typical carbide insert the poorer choice here.)

Enjoy,
DoN.
--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

"B.B." u wrote in message
news snip---
Harold, When you wrote "Can I assume the mandrel is ½?" that last
character came out as Pi on my screen, and I have no idea what you meant
by it.

Ooops!! Sorry about that----I hit the keys in the wrong sequence, and
didn't notice. It was intended to be ½" ?----asking the size of your
mandrel. My concern is that the more slender is the mandrel, the more
likely you would experience chatter.

But, bar stock, pressed the mandrel in with an arbor press.
We're using general-purpose indexable carbide tools on all of the
lathes, but I have a fresh bit of tool steel and I'll see about making
my own tool to play with.

If you understand rake and clearances, you'd be far better off, especially
if you're using negative rake inserts. If you're using positive rake and
they're sharp with a minimal corner radius, it may not make a big
difference. Regardless of what you have, I'd strongly encourage you to
learn to hand grind toolbits while you have someone looking over your
shoulder (assuming you do have, and they understand the concept themselves),
for it will serve you well for ever. It really is nice to not have to buy
each and every special type tool that you need when it may get used only
once.

Now that we understand you're using inserts, make sure you're not running a
C5 or C6 grade, especially if the insert has looked at steel first. It's
the wrong choice for non-ferrous materials to begin with, lacking the proper
edge hardness to withstand cuts. It really does make a huge difference.


I did find (counter-intuitively) that running
on the high side of the cutting speeds helped.

All metals have what you might call a "sweet spot", where they machine
better than at other speeds. Aluminum really responds well to high speeds,
and rarely is a problem as a result, assuming you use the right tools.
Armed with that knowledge, try to run as fast as possible, which generally
yields far better finishes and improved chip flow. You risk chatter, so
you must achieve a balance for conditions at hand. You can't always use the
speed you might desire. Run as fast as possible for conditions. The
larger the area of contact your part has with the tool, the more likely
you'll have chatter. Broad tools make for difficult operations unless you
have *very* rigid machines. If you were to compare the likes of a 17"
Axelson, for example, with a 10" Southbend (not a fair comparison, but it
really proves the point) it would jump right out at you. When you run a
lathe, try to keep everything choked up as close as possible. Material short
in the chuck, tailstock quill extended only as far as absolutely needed, and
cutting tools held as short as possible. When you keep everything close, you
can usually run faster, which yields better results and shortens machining
time. That can be real critical if you're making lots of the same thing.

I'll likely settle on the heat & press method suggested by
PrecisionMachinist. Class is on monday--I'll let you know how it goes.

Good luck! Hope you can give us a good report.

Harold

"DoN. Nichols" wrote in message
...
In article ,
B.B. u wrote:

[ ... ]

Harold, When you wrote "Can I assume the mandrel is ½?" that last
character came out as Pi on my screen, and I have no idea what you meant
by it.

It comes out as "1/2" on some screens, but since it is a part of
the extended ASCII character set, there are no promises that it will
show up the same on all. This is a primary reason for sticking to only
the characters which show on the tops of your keyboard keys. Anything
which requires fancy keyboard tricks to generate (e.g. Compose-1-2 on my
Sun keyboard) will not mean the same to everybody in this newsgroup with
mixed systems in mixed locations around the world. (And it even chances
on some of them when you change the characterset used by the program.

That's one thing I need to try to keep in mind. I'm fairly comfortable with
a half dozen characters so generated and use them routinely. Probably not a
good idea when posting! Thanks, DoN.

But, bar stock, pressed the mandrel in with an arbor press.

Hmm ... bar stock? Not turned to have a very slight taper?

His answer is likely no, and it shouldn't have. Arbors have a gentle taper
and will hold an item squarely, assuming the mandrel is pressed properly and
the item held isn't very narrow.

That could be part of the problem. I think that the typical taper on an
arbor for turning between centers is 0.001 inch/foot, but I'm sure that
Harold will correct me if I am wrong.

Close, but no cigar. Standard taper is .0005"/inch. A tiny taper like
you propose would necessitate a huge array of mandrels to be useful for
run-of-the-mill parts, unless a very tight tolerance was imposed. They
would also have the ability to swage holes effortlessly, which could be a
bad idea depending on circumstances at hand. Mandrels are often used on
grinding machines, where one is grinding the likes of bushings that must be
dead concentric. Hone first for size and finish, then grind. I've ground
literally thousands of bushings in that fashion.

We're using general-purpose indexable carbide tools on all of the
lathes, but I have a fresh bit of tool steel and I'll see about making
my own tool to play with.

That could help, as typically a carbide insert is not as sharp
as a frechly ground and honed HSS bit.

Yep! Rarely do you find inserts that rival honed HSS tools, but they do
exist. I use RB inserts that are diamond ground. Very nice inserts, and
sharp, so long as you don't buy them coated. Even the coated ones are
fairly sharp, however.


If your arbors *do* have a taper, it should get it that much
tighter. (Also note that the heat generated by turning could expand the
aluminum and loosen the grip on the steel arbor, which would make the
typical carbide insert the poorer choice here.)

Yeah, all a part of that delicate balance one must achieve. In practice,
one might never use a mandrel. They are slow, cumbersome devices that
limit the ability to machine anything. Soft jaws are often used instead,
or any of a myriad of setup variations, anything to improve driving
capability and cutting ability. Still, they're a very important part of
learning to run machines, exposing the newbie to precise ways to achieve
certain functions. Learn any and all of these procedures, and learn them
well. Later on, when you have better processes at your disposal, you'll
incorporate them when appropriate. Right now you're learning the basics,
and that's the best way to progress.

Harold

In article ,
(DoN. Nichols) wrote:

In article ,
B.B. u wrote:

[ ... ]

Harold, When you wrote "Can I assume the mandrel is ½?" that last
character came out as Pi on my screen, and I have no idea what you meant
by it.

It comes out as "1/2" on some screens, but since it is a part of
the extended ASCII character set, there are no promises that it will
show up the same on all. This is a primary reason for sticking to only
the characters which show on the tops of your keyboard keys. Anything
which requires fancy keyboard tricks to generate (e.g. Compose-1-2 on my
Sun keyboard) will not mean the same to everybody in this newsgroup with
mixed systems in mixed locations around the world. (And it even chances
on some of them when you change the characterset used by the program.

But, bar stock, pressed the mandrel in with an arbor press.

Hmm ... bar stock? Not turned to have a very slight taper?
That could be part of the problem. I think that the typical taper on an
arbor for turning between centers is 0.001 inch/foot, but I'm sure that
Harold will correct me if I am wrong.

Oh, the mandrel itself is tapered--it's a pre-made mandrel out of a
box. I thought Harold was asking if I was turning my part from either
cast or bar stock. I'm turning from bar stock, and the part is pressed
onto a mandrel. Hope that clears it up.

We're using general-purpose indexable carbide tools on all of the
lathes, but I have a fresh bit of tool steel and I'll see about making
my own tool to play with.

That could help, as typically a carbide insert is not as sharp
as a frechly ground and honed HSS bit.

Note that I have some very nice sharp solid carbide inserts
(1/4" IC 55 degree diamond *without* TiN coating or the like, which I
use when I want a sharp tool but am too lazy to grind my own. :-)

I did find (counter-intuitively) that running
on the high side of the cutting speeds helped.
I'll likely settle on the heat & press method suggested by
PrecisionMachinist. Class is on monday--I'll let you know how it goes.

If your arbors *do* have a taper, it should get it that much
tighter. (Also note that the heat generated by turning could expand the
aluminum and loosen the grip on the steel arbor, which would make the
typical carbide insert the poorer choice here.)

Yeah, maybe I'll just turn it until it starts slipping and then run
it over to the press while still hot.

--
B.B. --I am not a goat! thegoat4 at airmail dot net
http://web2.airmail.net/thegoat4/

In article ,
"Harold and Susan Vordos" wrote:

"B.B." u wrote in message
news snip---
Harold, When you wrote "Can I assume the mandrel is ½?" that last
character came out as Pi on my screen, and I have no idea what you meant
by it.

Ooops!! Sorry about that----I hit the keys in the wrong sequence, and
didn't notice. It was intended to be ½" ?----asking the size of your
mandrel. My concern is that the more slender is the mandrel, the more
likely you would experience chatter.

It's a skinny little 3/8 mandrel and 6" long while my part was only
3/4" long. I had a chatter problem at first (I did kinda like the funky
looking finish, though) but it went away as soon as I limited myself to
passes of .010 or less. Not a problem since I'm only making one wheel
and only needed to shave off about .070 anyway.

But, bar stock, pressed the mandrel in with an arbor press.
We're using general-purpose indexable carbide tools on all of the
lathes, but I have a fresh bit of tool steel and I'll see about making
my own tool to play with.

If you understand rake and clearances, you'd be far better off, especially
if you're using negative rake inserts. If you're using positive rake and
they're sharp with a minimal corner radius, it may not make a big
difference. Regardless of what you have, I'd strongly encourage you to
learn to hand grind toolbits while you have someone looking over your
shoulder (assuming you do have, and they understand the concept themselves),
for it will serve you well for ever. It really is nice to not have to buy
each and every special type tool that you need when it may get used only
once.

Now that we understand you're using inserts, make sure you're not running a
C5 or C6 grade, especially if the insert has looked at steel first. It's
the wrong choice for non-ferrous materials to begin with, lacking the proper
edge hardness to withstand cuts. It really does make a huge difference.

How would I check a carbide for its grade? Would it be embossed on
the inset itself, or would I simply have to check the package it came
out of?

I did find (counter-intuitively) that running
on the high side of the cutting speeds helped.

All metals have what you might call a "sweet spot", where they machine
better than at other speeds. Aluminum really responds well to high speeds,
and rarely is a problem as a result, assuming you use the right tools.
Armed with that knowledge, try to run as fast as possible, which generally
yields far better finishes and improved chip flow. You risk chatter, so
you must achieve a balance for conditions at hand. You can't always use the
speed you might desire. Run as fast as possible for conditions. The
larger the area of contact your part has with the tool, the more likely
you'll have chatter. Broad tools make for difficult operations unless you
have *very* rigid machines. If you were to compare the likes of a 17"
Axelson, for example, with a 10" Southbend (not a fair comparison, but it
really proves the point) it would jump right out at you. When you run a
lathe, try to keep everything choked up as close as possible. Material short
in the chuck, tailstock quill extended only as far as absolutely needed, and
cutting tools held as short as possible. When you keep everything close, you
can usually run faster, which yields better results and shortens machining
time. That can be real critical if you're making lots of the same thing.

I'll likely settle on the heat & press method suggested by
PrecisionMachinist. Class is on monday--I'll let you know how it goes.

Good luck! Hope you can give us a good report.

Harold

--
B.B. --I am not a goat! thegoat4 at airmail dot net
http://web2.airmail.net/thegoat4/

"B.B." u wrote in message
news
In article ,
"Harold and Susan Vordos" wrote:
snip------

It's a skinny little 3/8 mandrel and 6" long while my part was only
3/4" long. I had a chatter problem at first (I did kinda like the funky
looking finish, though) but it went away as soon as I limited myself to
passes of .010 or less. Not a problem since I'm only making one wheel
and only needed to shave off about .070 anyway.


That's even worse than I had expected. While I realize that the number of
passes you may have to take isn't of importance at this point, I think you
can understand that if you were engaged in doing this for gain, you'd be out
of business before you got started. Again, you're in a learning phase
right now, so it's important to experience these things so you understand
them.

Holding by other means, you'd have roughed the flywheel within .03"/side,
then taken appropriate finish cuts of equal sizes for consistent tool load.
One to determine size, the balance (2 passes) splitting the remaining
material, half for each pass. That way you can better control diameter when
it's critical. Certainly, the outside of a flywheel isn't, but it's a good
method to learn for when your project demands precision.


How would I check a carbide for its grade? Would it be embossed on
the inset itself, or would I simply have to check the package it came
out of?

Depends on the maker. Some carbide is identified on each piece, but you
can't rely on that. The C2 designation might appear as something else, so
you have to understand carbide markings for it to make sense. For
example, if you're using Carboloy, their C2 grade would be marked 883, and
C5 would most likely be marked 370. Understand that any carbide will cut
any material, but how they hold up is determined by the grade. C2 has
excellent edge hardness, but is brittle and chips easily. Not a problem when
machining aluminum, but when you machine steel, unless you're taking very
light cuts, it tends to chip the edges around the point of contact, the
result of chips acting against the carbide. The point may very well stay
intact and still cut fine, but if you use the tool for a deeper pass than
the previous one, it often breaks because the tool has lost proper
configuration because of edge erosion.

In the old days, (carbide) makers talked about a triangle. If your choice
gave problems, you moved around the triangle. As you gain one feature, you
give up two others. There's usually a balance of the three features that
will provide good tool service and life. I'm not sure they even talk
about that today, it's been years since I last had to worry about carbide
grades. If you can find some old Kennametal data, they used to include
the triangle, and it would help you understand how it works. It's been too
long for me to recall it correctly.

What's important here is that your insert hasn't been machining steel before
using it on aluminum, even if it's the right grade. The keen edge will be
gone, and without that you're likely to have problems. Finish often speaks
volumes about the condition of the cutting edge, even when you think
everything is OK. If you're machining 6061-T6, you should expect the
surface to show feed marks, but otherwise cut quite cleanly, with no
fuzziness on the surface, assuming you're using a lubricant. If you get the
slightest signs of fuzziness, the edge is likely experiencing some chip
welding, maybe at the microscopic level. That makes for poor machining and
increased cutting pressure. That works against you when using a mandrel,
especially when you're driving with such a small diameter. Knowing the
size you're using, I'd suggest what you're experiencing is more or less
normal. That's why you try to avoid using mandrels. I also avoid turning
between centers as much as I can. Same problem. Too much chatter and the
cuts demanded can't be accomplished. Soft jaws answer the vast majority of
the problems. It's a little too early for you to worry about them at this
point. Besides, the chuck you're using may not accommodate them. Not all
chucks do.

Harold

In article ,
"Harold and Susan Vordos" wrote:

"B.B." u wrote in message
news
In article ,
"Harold and Susan Vordos" wrote:
snip------

It's a skinny little 3/8 mandrel and 6" long while my part was only
3/4" long. I had a chatter problem at first (I did kinda like the funky
looking finish, though) but it went away as soon as I limited myself to
passes of .010 or less. Not a problem since I'm only making one wheel
and only needed to shave off about .070 anyway.


That's even worse than I had expected. While I realize that the number of
passes you may have to take isn't of importance at this point, I think you
can understand that if you were engaged in doing this for gain, you'd be out
of business before you got started. Again, you're in a learning phase
right now, so it's important to experience these things so you understand
them.

Holding by other means, you'd have roughed the flywheel within .03"/side,
then taken appropriate finish cuts of equal sizes for consistent tool load.
One to determine size, the balance (2 passes) splitting the remaining
material, half for each pass. That way you can better control diameter when
it's critical. Certainly, the outside of a flywheel isn't, but it's a good
method to learn for when your project demands precision.

We lose 10 points each time we restart a part, but I'm taking the
class to learn--not necessarily to fluff my GPA. I may very well do
another wheel simply for the hell of it.
Either that or when I get to make my own project up after finishing
this one I'll do something with a wheel on it.

How would I check a carbide for its grade? Would it be embossed on
the inset itself, or would I simply have to check the package it came
out of?

Depends on the maker. Some carbide is identified on each piece, but you
can't rely on that. The C2 designation might appear as something else, so
you have to understand carbide markings for it to make sense. For
example, if you're using Carboloy, their C2 grade would be marked 883, and
C5 would most likely be marked 370. Understand that any carbide will cut
any material, but how they hold up is determined by the grade. C2 has
excellent edge hardness, but is brittle and chips easily. Not a problem when
machining aluminum, but when you machine steel, unless you're taking very
light cuts, it tends to chip the edges around the point of contact, the
result of chips acting against the carbide. The point may very well stay
intact and still cut fine, but if you use the tool for a deeper pass than
the previous one, it often breaks because the tool has lost proper
configuration because of edge erosion.

So what does the C2/C5 rating refer to? Grain size? Carbide vs.
"other" content? Is there some sort of system to choose which grade
where, or is it just down to C2 for some stuff, C5 for others, all other
grades not made anymore?
Searching on google got me a whole lot of marketing, but not much
else.

In the old days, (carbide) makers talked about a triangle. If your choice
gave problems, you moved around the triangle. As you gain one feature, you
give up two others. There's usually a balance of the three features that
will provide good tool service and life. I'm not sure they even talk
about that today, it's been years since I last had to worry about carbide
grades. If you can find some old Kennametal data, they used to include
the triangle, and it would help you understand how it works. It's been too
long for me to recall it correctly.

Sounds like bicycle parts: cheap, durable, light--pick two.

What's important here is that your insert hasn't been machining steel before
using it on aluminum, even if it's the right grade. The keen edge will be
gone, and without that you're likely to have problems. Finish often speaks
volumes about the condition of the cutting edge, even when you think
everything is OK. If you're machining 6061-T6, you should expect the
surface to show feed marks, but otherwise cut quite cleanly, with no
fuzziness on the surface, assuming you're using a lubricant. If you get the
slightest signs of fuzziness, the edge is likely experiencing some chip
welding, maybe at the microscopic level. That makes for poor machining and
increased cutting pressure. That works against you when using a mandrel,
especially when you're driving with such a small diameter. Knowing the
size you're using, I'd suggest what you're experiencing is more or less
normal. That's why you try to avoid using mandrels. I also avoid turning
between centers as much as I can. Same problem. Too much chatter and the
cuts demanded can't be accomplished. Soft jaws answer the vast majority of
the problems. It's a little too early for you to worry about them at this
point. Besides, the chuck you're using may not accommodate them. Not all
chucks do.

These inserts get used on any damn thing that finds its way onto the
lathes. Poor things probably had to cut stone at some point. In fact,
I had to put a steel center into the chuck and take a light cut off of
it so the mandrel would run true immediately before I machined the
wheel. So, yeah, it got "steeled" first.
Would the steel or aluminum--not both rule also apply to HSS bits, or
are they OK with it since they can be sharpened?
I wound up leaving the outside of my flywheel .003" oversize (we have
a tolerance of .005" over/under) so I could file/sand off the uglyness.
Alas, there is no lubricant. I did try painting my wheel with a film
of oil for one cut, but it didn't appear to help any, so I didn't mess
with it any more. Got a bit stinky anyhow.
My lathe actually had two carbides sitting at it. One was undamaged,
but the other had an impressive little heap of metal welded firmly to
the cutting edge.
But that's really nothing compared to the guy who took a .050" pass
using a carbide insert cutter in the mill, but ran it backwards and way
too fast. It took off .050, but as a smear instead of as chips. Ah,
school.

--
B.B. --I am not a goat! thegoat4 at airmail dot net
http://web2.airmail.net/thegoat4/

"Harold and Susan Vordos" wrote in message
...

"PrecisionMachinisT" wrote in message
...

"Nick Hull" wrote in message
...
In article ,
"PrecisionMachinisT" wrote:

The "splitting" part is what becomes the problem here--it's best
done
in
this case with just a plain ole hacksaw....with the mandrel still
firmly
chucked in the lathe....

From start to finish, once you chuck your mandrel blank you should
forget
that you even *own* a chuck key--throw the darned thing out the bay
door
and
retrieve it later......cause if you unchuck the work and have to
re-set
it
then all bets are off....

Nothing says the chuck has to remain on the lathe, just the mandrel
stays in the chuck.


While most mounts are pretty darned accurate, I wouldnt bet on it
without
having some familarity with the actual lathe thats being used.


Agreed!

While the error is usually minor, even with a D type spindle, orientation
affects concentricity in many instances. Many of the D type spindles
have
a witness mark for that reason.

Harold


Or there might have been a little dirt or chip someplace from the last guy
that installed the chuck....

--

SVL

"B.B." u wrote in message
news
In article ,
"Harold and Susan Vordos" wrote:
snip--

So what does the C2/C5 rating refer to? Grain size? Carbide vs.
"other" content? Is there some sort of system to choose which grade
where, or is it just down to C2 for some stuff, C5 for others, all other
grades not made anymore?
Searching on google got me a whole lot of marketing, but not much
else.

I've been out of the shop so long that I am no longer knowledgeable where
carbides are concerned. It's particularly bad considering they've made
great strides with carbide, too, so I can only assume that it may not be as
critical as it once was. I'm not convinced you'd find many machinists
that really understood the differences in how they're put together, though.
When you go back to my time in the shop (primarily brazed carbides),
constituents of the carbide were altered to accomplish the performance
required. Carbide went from hard to strong, and from edge wear resistant
to crater resistant. As you moved from one feature towards another, you
gained certain qualities, but lost others. It could be that today it's
just not as important. Dunno.



These inserts get used on any damn thing that finds its way onto the
lathes. Poor things probably had to cut stone at some point. In fact,
I had to put a steel center into the chuck and take a light cut off of
it so the mandrel would run true immediately before I machined the
wheel. So, yeah, it got "steeled" first.

Your chance of accomplishing good cuts is way down. It would be especially
true if the carbide is intended for machining steel, which I would imagine
it is.

Would the steel or aluminum--not both rule also apply to HSS bits, or
are they OK with it since they can be sharpened?

HSS is not as critical as to how it's applied, but when it is a concern, one
selects tool steel high in cobalt, which offers tougher conditions at
elevated temperatures. Any HSS will work for aluminum, especially if you
understand chip breakers and rake angles. You can create tools that will
peel it off faster than you can imagine. Lubrication is very important,
however. It doesn't take much, something as simple as brush application
works fine. Kerosene is the lubricant of choice for aluminum, but almost
anything is better than nothing. I've used Stoddard solvent that isn't real
clean with great success, but if you'd like things to smell nice, consider a
small can of WD-40. It appears to be nothing more than solvent with a
little wax dissolved in it, along with a perfume. It works fine for
aluminum.

It was common practice to have a small can on the machine with an acid brush
in it. To keep the can from getting blown about by the air hose (they're
use extensively in production shops, believe it or not) you'd place a piece
of stock in the bottom. I've always had a can of kerosene and sulfur based
oil at my lathe and mill.


I wound up leaving the outside of my flywheel .003" oversize (we have
a tolerance of .005" over/under) so I could file/sand off the uglyness.
Alas, there is no lubricant. I did try painting my wheel with a film
of oil for one cut, but it didn't appear to help any, so I didn't mess
with it any more. Got a bit stinky anyhow.
My lathe actually had two carbides sitting at it. One was undamaged,
but the other had an impressive little heap of metal welded firmly to
the cutting edge.

With the inserts you described, it's no wonder. Once you find chip
welding on an insert, for all practical purposes, it's no longer a good
insert. The welding generally occurs because of tip flaking or cratering,
with the chips welding into the rough edge or surface. There's usually no
way in hell it will cut well once that happens.


But that's really nothing compared to the guy who took a .050" pass
using a carbide insert cutter in the mill, but ran it backwards and way
too fast. It took off .050, but as a smear instead of as chips. Ah,
school.

Carbide is so weak in tensile that a tool that backs up ever so slightly is
usually ruined. Running a cutter backwards is a sure recipe for
destruction. You must have witnessed a hell of a lot of sparking unless he
was machining aluminum.

You'll come to realize that not everyone in your class will have the same
dedication to learning as you may have. I took a welding class several
years ago. One of the students was a druggie, and wasn't interested in the
least in learning anything. He took advantage of circumstances for reasons
best known to him. Didn't make sense to me, but it apparently did to him.
Sigh! He finally quit showing up-----

Harold

In article ,
"Harold and Susan Vordos" wrote:

"B.B." u wrote in message
news
In article ,
"Harold and Susan Vordos" wrote:
snip--

So what does the C2/C5 rating refer to? Grain size? Carbide vs.
"other" content? Is there some sort of system to choose which grade
where, or is it just down to C2 for some stuff, C5 for others, all other
grades not made anymore?
Searching on google got me a whole lot of marketing, but not much
else.

I've been out of the shop so long that I am no longer knowledgeable where
carbides are concerned. It's particularly bad considering they've made
great strides with carbide, too, so I can only assume that it may not be as
critical as it once was. I'm not convinced you'd find many machinists
that really understood the differences in how they're put together, though.
When you go back to my time in the shop (primarily brazed carbides),
constituents of the carbide were altered to accomplish the performance
required. Carbide went from hard to strong, and from edge wear resistant
to crater resistant. As you moved from one feature towards another, you
gained certain qualities, but lost others. It could be that today it's
just not as important. Dunno.

I'll do some more digging on carbides and grades. If I find anything
juicy I'll post it in RCM. Seems like something that would be nice to
know.

These inserts get used on any damn thing that finds its way onto the
lathes. Poor things probably had to cut stone at some point. In fact,
I had to put a steel center into the chuck and take a light cut off of
it so the mandrel would run true immediately before I machined the
wheel. So, yeah, it got "steeled" first.

Your chance of accomplishing good cuts is way down. It would be especially
true if the carbide is intended for machining steel, which I would imagine
it is.

I'm sure it is too. Would an aluminum-cutting setup involve only a
different insert, or also a different insert holder. IIRC, the holders
out there have a negative rake (angles down towards the work, which I
believe is called negative) and a negative side-rake. (down towards the
headstock) Are the rake angles a function of the holders, or are all
holders angles this way, expecting the lip on the edge of the carbide to
determine back/side rake?

Would the steel or aluminum--not both rule also apply to HSS bits, or
are they OK with it since they can be sharpened?

HSS is not as critical as to how it's applied, but when it is a concern, one
selects tool steel high in cobalt, which offers tougher conditions at
elevated temperatures. Any HSS will work for aluminum, especially if you
understand chip breakers and rake angles. You can create tools that will
peel it off faster than you can imagine. Lubrication is very important,
however. It doesn't take much, something as simple as brush application
works fine. Kerosene is the lubricant of choice for aluminum, but almost
anything is better than nothing. I've used Stoddard solvent that isn't real
clean with great success, but if you'd like things to smell nice, consider a
small can of WD-40. It appears to be nothing more than solvent with a
little wax dissolved in it, along with a perfume. It works fine for
aluminum.

Rake angles I think I've got a handle on. At least enough to get
started. As I understand it a chip breaker is just a little groove some
ways back from the cutting edge, correct?

It was common practice to have a small can on the machine with an acid brush
in it. To keep the can from getting blown about by the air hose (they're
use extensively in production shops, believe it or not) you'd place a piece
of stock in the bottom. I've always had a can of kerosene and sulfur based
oil at my lathe and mill.

Is diesel close enough to kerosene to work? I can get a little
container of diesel easy, but kerosene will be a hassle. I'm in texas,
so our diesel is as sulphury as law allows. (:

I wound up leaving the outside of my flywheel .003" oversize (we have
a tolerance of .005" over/under) so I could file/sand off the uglyness.
Alas, there is no lubricant. I did try painting my wheel with a film
of oil for one cut, but it didn't appear to help any, so I didn't mess
with it any more. Got a bit stinky anyhow.
My lathe actually had two carbides sitting at it. One was undamaged,
but the other had an impressive little heap of metal welded firmly to
the cutting edge.

With the inserts you described, it's no wonder. Once you find chip
welding on an insert, for all practical purposes, it's no longer a good
insert. The welding generally occurs because of tip flaking or cratering,
with the chips welding into the rough edge or surface. There's usually no
way in hell it will cut well once that happens.

Good to know. Thanks.

But that's really nothing compared to the guy who took a .050" pass
using a carbide insert cutter in the mill, but ran it backwards and way
too fast. It took off .050, but as a smear instead of as chips. Ah,
school.

Carbide is so weak in tensile that a tool that backs up ever so slightly is
usually ruined. Running a cutter backwards is a sure recipe for
destruction. You must have witnessed a hell of a lot of sparking unless he
was machining aluminum.

It was aluminum. Now I can't wait for someone to do it with a steel
piece so I can watch the sparks! (: Before I ever use a cutter out of
the "studentized" cabinet I always check it first. I think I know which
one he used because it's covered in rubbing marks and two of the three
inserts are missing the tips. The teacher says he's going to leave it
in the cabinet for the rest of the semester so people will learn to look
at their tools before using them.

You'll come to realize that not everyone in your class will have the same
dedication to learning as you may have. I took a welding class several
years ago. One of the students was a druggie, and wasn't interested in the
least in learning anything. He took advantage of circumstances for reasons
best known to him. Didn't make sense to me, but it apparently did to him.
Sigh! He finally quit showing up-----

Heh, over in my welding class two weeks back some guy showed up for
the first time since the beginning of the semester. The teacher simply
told him up-front that he hasn't been there, his excuse (broke down
truck) was bull****, and he would do nothing more than waste his and the
teacher's time and a whole bunch of electricity. Kicked him out on the
spot. I like that teacher!
In my machining class we've gone from 12 down to seven or six
students. Probably going to be five by the end of the semester.
Welding is worse, started with 11, down to six who show up at all, and
it'll likely be three of us by the end. OTOH, my other classes are
grad-level and our flaky guys are the ones who've missed as many as
three days. (:

--
B.B. --I am not a goat! thegoat4 at airmail dot net
http://web2.airmail.net/thegoat4/

In article DoNotSpamthegoat4-87661B.09280206032005
@readit2.airnews.net, DoNotSpamthegoat4

Is diesel close enough to kerosene to work? I can get a little
container of diesel easy, but kerosene will be a hassle. I'm in texas,
so our diesel is as sulphury as law allows. (:


Diesel will work, or you can buy a jug of lamp oil at Wally World for a
few bucks. It's just deodorized kerosene, which is the major component
of WD-40. You can even get it with a pleasant floral scent (yuk).

Ned Simmons

In article , Harold and Susan Vordos says...

HSS is not as critical as to how it's applied, but when it is a concern, one
selects tool steel high in cobalt, which offers tougher conditions at
elevated temperatures. Any HSS will work for aluminum, especially if you
understand chip breakers and rake angles.

It'll work fine even if he doesn't have a chipbreaker - but has a
sharp tool with even reasonable postive rake. I'm suprised this
wasn't more of an issue here - my experience with *coated* carbide
inserts is that they actually work pretty poorly for aluminum,
especially so for small depth cuts. Coated inserts have a honed
edge so the coating will adhere well - but that feature effective
turns them into negative rake tools for small depth cuts.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

"jim rozen" wrote in message
...
In article , Harold and Susan Vordos says...

HSS is not as critical as to how it's applied, but when it is a concern,
one
selects tool steel high in cobalt, which offers tougher conditions at
elevated temperatures. Any HSS will work for aluminum, especially if
you
understand chip breakers and rake angles.

It'll work fine even if he doesn't have a chipbreaker - but has a
sharp tool with even reasonable postive rake. I'm suprised this
wasn't more of an issue here - my experience with *coated* carbide
inserts is that they actually work pretty poorly for aluminum,
especially so for small depth cuts. Coated inserts have a honed
edge so the coating will adhere well - but that feature effective
turns them into negative rake tools for small depth cuts.

Jim


It's taken this many exchanged for the fact that he is using a negative rake
tool, not a positive rake one, to surface. At this point I'm beginning to
question the ability of the instructor. I can't imagine a poorer
combination if I tried-------a chip welded negative rake insert on aluminum.
Changing to a HSS tool, properly ground, one would experience an astonishing
level of improvement.

I agree---the coated inserts are likely a poor choice, but there are no good
choices when it comes to negative rake and aluminum. It screams for
positive rake for good performance. Positive rake, with a proper chip
breaker. There is little to be gained by using negative rake for
aluminum.

For the most part, I rarely grind a rake angle without incorporating a chip
breaker. The sole exception is parting tools, where I use the radius of the
wheel to grind the top of the tool, generating a small amount of positive
rake, but improving chip flow tremendously. As you likely know, too much
rake on a parting tool encourages hogging, a serious problem on light duty
machines.

Chip flow is usually a serous consideration when machining aluminum. I
don't like to generate strings, so by grinding a chip breaker, rather broad
and somewhat deep (according to need) I can usually end up with small broken
curls, the ideal chip. Cutting pressure is at a minimum.

Harold

In article , Harold and Susan Vordos says...

It's taken this many exchanged for the fact that he is using a negative rake
tool, not a positive rake one, to surface. At this point I'm beginning to
question the ability of the instructor. I can't imagine a poorer
combination if I tried-------a chip welded negative rake insert on aluminum.
Changing to a HSS tool, properly ground, one would experience an astonishing
level of improvement.

Oh. I missed that. Though, if he's using coated carbide, he
probably would effective have a negative rake tool even if it were
in a positive holder for tpg inserts.

I agree---the coated inserts are likely a poor choice, but there are no good
choices when it comes to negative rake and aluminum. It screams for
positive rake for good performance. Positive rake, with a proper chip
breaker. There is little to be gained by using negative rake for
aluminum.

Is there *anything* to be gained, ever?

He could have made 100 of those flywheels with a HSS tool ground
with only three grinds, and a proper mandreal and pusher block,
in one day.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

"B.B." u wrote in message
news
In article ,
"Harold and Susan Vordos" wrote:

"B.B." u wrote in
message
news
In article ,
"Harold and Susan Vordos" wrote:
snip--

So what does the C2/C5 rating refer to? Grain size? Carbide vs.
"other" content? Is there some sort of system to choose which grade
where, or is it just down to C2 for some stuff, C5 for others, all
other
grades not made anymore?
Searching on google got me a whole lot of marketing, but not much
else.

I've been out of the shop so long that I am no longer knowledgeable
where
carbides are concerned. It's particularly bad considering they've made
great strides with carbide, too, so I can only assume that it may not be
as
critical as it once was. I'm not convinced you'd find many machinists
that really understood the differences in how they're put together,
though.
When you go back to my time in the shop (primarily brazed carbides),
constituents of the carbide were altered to accomplish the performance
required. Carbide went from hard to strong, and from edge wear
resistant
to crater resistant. As you moved from one feature towards another,
you
gained certain qualities, but lost others. It could be that today it's
just not as important. Dunno.

I'll do some more digging on carbides and grades. If I find anything
juicy I'll post it in RCM. Seems like something that would be nice to
know.

Agreed. Very few seem to grasp the significance of choosing the proper
grade. I'd welcome anything you can uncover.


I'm sure it is too. Would an aluminum-cutting setup involve only a
different insert, or also a different insert holder. IIRC, the holders
out there have a negative rake (angles down towards the work, which I
believe is called negative) and a negative side-rake. (down towards the
headstock) Are the rake angles a function of the holders, or are all
holders angles this way, expecting the lip on the edge of the carbide to
determine back/side rake?

There are holders that determine rake angle, such as the negative rake types
you're apparently using, but there are inserts with grinds that can alter
the rake angle to some degree. It's conceivable to have negative rake
holders that have positive rake inserts, but they're usually somewhat timid
in performance. The edges are relatively fragile and easily chipped, so
they're usually used for light cuts only.

I'm shaking my head in disbelief as I read you're being taught to use a
negative rake holder with aluminum, however. You couldn't come up with
any worse combination than you have. Even for roughing, positive rake is a
better choice in aluminum. It requires far less horse power. The material,
being quite soft and low in tensile, machines very easily. There is little
benefit in using negative rake, and it goes from a bad idea to a horrible
one for finishing. Negative rake tools don't cut at the tip, but rely
instead on what is known as a false cutting edge. The cut occurs back of
the tip, where cratering is generated. When you try to take light cuts,
the tip comes into play and isn't up to the task. Long ago, it was
recommended that a slight chamfer (.005") be stoned on the tip to discourage
chipping, prolonging the useful life of the insert. You can imagine how
poorly it would perform when taking a light cut. It's not a good idea to
use negative rake for finishing, not even in steel, although if the cuts are
heavy enough, it works fine. You really should be using positive rake,
and a sharp tool, with no chip welding of any kind.

Positive rake tools generally have a cutting edge on one side of the insert
only, so a triangular insert has only three cutting tips, not six.


Would the steel or aluminum--not both rule also apply to HSS bits,
or
are they OK with it since they can be sharpened?

HSS is not as critical as to how it's applied, but when it is a concern,
one
selects tool steel high in cobalt, which offers tougher conditions at
elevated temperatures. Any HSS will work for aluminum, especially if
you
understand chip breakers and rake angles. You can create tools that will
peel it off faster than you can imagine. Lubrication is very important,
however. It doesn't take much, something as simple as brush application
works fine. Kerosene is the lubricant of choice for aluminum, but almost
anything is better than nothing. I've used Stoddard solvent that isn't
real
clean with great success, but if you'd like things to smell nice,
consider a
small can of WD-40. It appears to be nothing more than solvent with a
little wax dissolved in it, along with a perfume. It works fine for
aluminum.

Rake angles I think I've got a handle on. At least enough to get
started. As I understand it a chip breaker is just a little groove some
ways back from the cutting edge, correct?

Yes, that's correct, but it's a good idea to incorporate a chip breaker as
your rake angle. It takes a little grinding experience to get good at it,
but it really pays benefits. A simple rake angle improves machining
ability, but creates horrible chip problems. When you couple the chip
breaker with the rake angle, all that goes away. If nothing else, you gain
considerable safety, not generating long strings that can wrap around your
spinning object.

It was common practice to have a small can on the machine with an acid
brush
in it. To keep the can from getting blown about by the air hose
(they're
use extensively in production shops, believe it or not) you'd place a
piece
of stock in the bottom. I've always had a can of kerosene and sulfur
based
oil at my lathe and mill.

Is diesel close enough to kerosene to work? I can get a little
container of diesel easy, but kerosene will be a hassle. I'm in texas,
so our diesel is as sulphury as law allows. (:

I own a couple Dodge diesels, and hate the smell of the fuel. I've never
tried it, but I can't imagine it wouldn't work. I used Stoddard in place
of kerosene to get away from the smell, which is similar to diesel. If
you have a (Stoddard) solvent container for cleaning parts, just dip a
little out as needed. I've done that for years. Sulfur is very much a part
of lubricating when machining. One of the best oils for machining steel is
sulfur based cutting oil. The stinky stuff.

I wound up leaving the outside of my flywheel .003" oversize (we
have
a tolerance of .005" over/under) so I could file/sand off the uglyness.
Alas, there is no lubricant. I did try painting my wheel with a
film
of oil for one cut, but it didn't appear to help any, so I didn't mess
with it any more. Got a bit stinky anyhow.
My lathe actually had two carbides sitting at it. One was
undamaged,
but the other had an impressive little heap of metal welded firmly to
the cutting edge.

With the inserts you described, it's no wonder. Once you find chip
welding on an insert, for all practical purposes, it's no longer a good
insert. The welding generally occurs because of tip flaking or
cratering,
with the chips welding into the rough edge or surface. There's usually
no
way in hell it will cut well once that happens.

Good to know. Thanks.

By now you grasp the importance of not using negative rake, hopefully. You
have enough material left to make one good pass and end up with a beautiful
surface. Don't blow it screwing around with the negative rake inserts.
If, by chance, you do, chalk it up to learning. You'll remember the screw up
far better than you would good success. Making mistakes is very much a
part of the learning process, especially on machines. You'll come to realize
that not everything is as it appears. Often you'll dial a cut and the
machine takes more or less than the amount you "requested". A good
machinist knows how to get around that problem. A loser rarely ever
figures it out.

You'll come to realize that not everyone in your class will have the same
dedication to learning as you may have. I took a welding class several
years ago. One of the students was a druggie, and wasn't interested in
the
least in learning anything. He took advantage of circumstances for
reasons
best known to him. Didn't make sense to me, but it apparently did to
him.
Sigh! He finally quit showing up-----

Heh, over in my welding class two weeks back some guy showed up for
the first time since the beginning of the semester. The teacher simply
told him up-front that he hasn't been there, his excuse (broke down
truck) was bull****, and he would do nothing more than waste his and the
teacher's time and a whole bunch of electricity. Kicked him out on the
spot. I like that teacher!

By the time we're old enough to attend such classes, we're expected to
behave as adults. People like him (and the druggie that was in my class)
have a way of disrupting the learning of those that are serious. I like
that teacher, too.

Harold

"jim rozen" wrote in message
...
In article , Harold and Susan Vordos says...

It's taken this many exchanged for the fact that he is using a negative
rake
tool, not a positive rake one, to surface. At this point I'm beginning
to
question the ability of the instructor. I can't imagine a poorer
combination if I tried-------a chip welded negative rake insert on
aluminum.
Changing to a HSS tool, properly ground, one would experience an
astonishing
level of improvement.

Oh. I missed that. Though, if he's using coated carbide, he
probably would effective have a negative rake tool even if it were
in a positive holder for tpg inserts.

I agree---the coated inserts are likely a poor choice, but there are no
good
choices when it comes to negative rake and aluminum. It screams for
positive rake for good performance. Positive rake, with a proper
chip
breaker. There is little to be gained by using negative rake for
aluminum.

Is there *anything* to be gained, ever?

I can envision a large object made of 7075-T6. Longer insert life. Still,
it would work fine with positive rake. I was just trying to leave the door
open ever so slightly for those that may swear negative is better. I've
never found it to be, but it works wonders when machining ductile or good
gray iron. Much better tool life. That's assuming the operator has
enough on the ball to know that it screams for a C2 grade of carbide.
That's more important than the rake angle.

He could have made 100 of those flywheels with a HSS tool ground
with only three grinds, and a proper mandreal and pusher block,
in one day.

Yep! I can't help but wonder how well equipped the instructor is at this
point. I can't think of a bigger disservice to anyone learning to machine
than to not instruct them on grinding (proper) cutting tools. Until one
understands cutting tool geometry, it's almost impossible to make decisions
to improve operations when things aren't going well. I consider myself to
be one very lucky person in that when I was trained, there was almost *no*
insert tooling, and each operator had to grind his own tools. It's
something that has served me very well. I rarely rely on inserts,
although I do use them. Mostly for roughing, however.

Harold

In article ,
"Harold and Susan Vordos" wrote:

[...]

I'm shaking my head in disbelief as I read you're being taught to use a
negative rake holder with aluminum, however.

It isn't really that we're being taught wrong as much as we're not
being taught about choosing cutting tools. Really, I'm using this class
in somewhat the wrong way--it's designed as a class to tech new kids
where all the knobs are, weed out slackers, and get everyone comfortable
around the equipment. Not so much a general introductory machining
class. Up until now, without knowing much at all about cutting tools
I've been making passable parts--they're just not pretty or fast. So it
would seem that they just chose a bunch of cutters that would survive a
semester of new students at a time and let the teacher cover a wider
range of material. In fact I believe the curriculum has a class
somewhere that's dedicated almost entirely to cutter angles, materials,
shapes, and physics.
Although I see the logic behind this, admittedly, I'd prefer at least
a couple of days on cutting physics. We are all going to make cutters
for threading, but that's not exactly the same thing as making a
generalized cutting tool.
I saw elsewhere in the thread you were starting to wonder about my
teacher's competence. As far as I can tell he's quite skilled and so
far every question I've brought to him has been answered. I figure if I
start using HSS tooling instead of the inserts he'll hang around me and
point out all the important stuff. It's just that this is a basic class
And as a bit of trivia, he's still got Kenneth McDuff's old toolbox.
Apparently, Mr. Sadist took this same class before he got arrested.

[...]

Rake angles I think I've got a handle on. At least enough to get
started. As I understand it a chip breaker is just a little groove some
ways back from the cutting edge, correct?

Yes, that's correct, but it's a good idea to incorporate a chip breaker as
your rake angle. It takes a little grinding experience to get good at it,
but it really pays benefits. A simple rake angle improves machining
ability, but creates horrible chip problems. When you couple the chip
breaker with the rake angle, all that goes away. If nothing else, you gain
considerable safety, not generating long strings that can wrap around your
spinning object.

Heh, I know how much of a pain it is to have a wad of razor wire get
snagged by the chuck and spun around at a few hundred RPM!
How would I incorporate a chip breaker into the rake angle? My
wild-assed guess would be to grind a too-shallow rake angle across the
whole top of the tool, then the proper rake angle only about half way
back. That would make a little hump just behind the cutting edge. Any
photos on the web of grinding chip breakers?
And how would I judge the effectiveness of a chipbreaker? Should I
expect to produce a bunch of little uniform chips, or should I just
expect the string to snap off every so often?

Is diesel close enough to kerosene to work? I can get a little
container of diesel easy, but kerosene will be a hassle. I'm in texas,
so our diesel is as sulphury as law allows. (:

I own a couple Dodge diesels, and hate the smell of the fuel. I've never
tried it, but I can't imagine it wouldn't work. I used Stoddard in place
of kerosene to get away from the smell, which is similar to diesel. If
you have a (Stoddard) solvent container for cleaning parts, just dip a
little out as needed. I've done that for years. Sulfur is very much a part
of lubricating when machining. One of the best oils for machining steel is
sulfur based cutting oil. The stinky stuff.

Ah, my day-job is diesel equipment buffoonery & repair, so I'm quite
accustomed to the smell. Even kind of like it. (: That's why I can
get it easily--have a (cleaned out) mustard bottle full of it already.
I have no idea what's in the bottles of cutting oil in the machine
shop. Some are quite thick, some are thin, all have different smells,
most are the color of fresh motor oil, some are the color of used, one
looks like gear oil, but doesn't smell like it, and another I swear is
water. Probably some good oil somewhere in that collection.
If I can find some known good cutting oil I'll use that.

With the inserts you described, it's no wonder. Once you find chip
welding on an insert, for all practical purposes, it's no longer a good
insert. The welding generally occurs because of tip flaking or
cratering,
with the chips welding into the rough edge or surface. There's usually
no
way in hell it will cut well once that happens.

Good to know. Thanks.

By now you grasp the importance of not using negative rake, hopefully. You
have enough material left to make one good pass and end up with a beautiful
surface. Don't blow it screwing around with the negative rake inserts.
If, by chance, you do, chalk it up to learning. You'll remember the screw up
far better than you would good success. Making mistakes is very much a
part of the learning process, especially on machines. You'll come to realize
that not everything is as it appears. Often you'll dial a cut and the
machine takes more or less than the amount you "requested". A good
machinist knows how to get around that problem. A loser rarely ever
figures it out.

Yeah, I did discover that. I found on the mill with the flycutter
around .015" cut will get me exactly what I intend, but less than that
usually cuts too much and more than that cuts too little. Or maybe it
was the other way around--last did anything over there was two weeks
back. Steel on the lathe was always right on once I quit mixing up the
inch and metric dials, but aluminum (oddly enough!) was pretty much
unpredictable -- always somewhere between -1 and +4 thou.

[...]

Sigh! He finally quit showing up-----

Heh, over in my welding class two weeks back some guy showed up for
the first time since the beginning of the semester. The teacher simply
told him up-front that he hasn't been there, his excuse (broke down
truck) was bull****, and he would do nothing more than waste his and the
teacher's time and a whole bunch of electricity. Kicked him out on the
spot. I like that teacher!

By the time we're old enough to attend such classes, we're expected to
behave as adults. People like him (and the druggie that was in my class)
have a way of disrupting the learning of those that are serious. I like
that teacher, too.

Harold

--
B.B. --I am not a goat! thegoat4 at airmail dot net
http://web2.airmail.net/thegoat4/

"B.B." u wrote in message
news
In article ,
"Harold and Susan Vordos" wrote:

[...]

I'm shaking my head in disbelief as I read you're being taught to use a
negative rake holder with aluminum, however.

It isn't really that we're being taught wrong as much as we're not
being taught about choosing cutting tools. Really, I'm using this class
in somewhat the wrong way--it's designed as a class to tech new kids
where all the knobs are, weed out slackers, and get everyone comfortable
around the equipment. Not so much a general introductory machining
class. Up until now, without knowing much at all about cutting tools
I've been making passable parts--they're just not pretty or fast. So it
would seem that they just chose a bunch of cutters that would survive a
semester of new students at a time and let the teacher cover a wider
range of material. In fact I believe the curriculum has a class
somewhere that's dedicated almost entirely to cutter angles, materials,
shapes, and physics.
Although I see the logic behind this, admittedly, I'd prefer at least
a couple of days on cutting physics. We are all going to make cutters
for threading, but that's not exactly the same thing as making a
generalized cutting tool.

In a sense, once you understand the geometry, it's all closely related.
Threading offers some challenges beyond normal turning because of the rapid
advance of the tool with coarse threads, so your side clearances have to be
modified. I gather you'll get to that eventually. I didn't realize your
class was not an introductory to machining, so I may have spoken out of
turn. Lets keep a watch and see what you're taught. Also, try to keep
in mind I'm an old school machinist, with absolutely no hands on with CNC
machinery. Many of the things that I hold dear and spelled success for me
may very well not be being taught now. However, for the guy with a manual
machine at home, knowing the things I learned spell total freedom.

I saw elsewhere in the thread you were starting to wonder about my
teacher's competence. As far as I can tell he's quite skilled and so
far every question I've brought to him has been answered. I figure if I
start using HSS tooling instead of the inserts he'll hang around me and
point out all the important stuff. It's just that this is a basic class
And as a bit of trivia, he's still got Kenneth McDuff's old toolbox.
Apparently, Mr. Sadist took this same class before he got arrested.

I'm afraid you have me at a disadvantage. Kenneth McDuff? Doesn't ring
a bell.

[...]

Rake angles I think I've got a handle on. At least enough to get
started. As I understand it a chip breaker is just a little groove
some
ways back from the cutting edge, correct?

It can be as little as a line ground parallel to, and slightly back from,
the cutting edge. Anything to disrupt the flow of the chip and cause it to
start winding will usually suffice. Needless to say, it relies on depth of
cut and feed rate for proper performance, so there's no hard and fast rule
on how to grind them. Deep cuts with heavy feed require a fairly wide
groove so the chip doesn't stack up as it makes the turn. Often the
breaker will wind the chip perfectly, but they won't break. I usually will
live with that scenario, especially if the long curls fall of the side of
the carriage peacefully. Anything to avoid the long strings.

So then, with the grind we're talking about, you can see that if you use the
corner of a wheel that has a small radius dressed on it, you can grind a
chip breaker that goes full positive at the cutting edge, then slowly goes
from positive to negative, rolling the chip in the process. This design has
the added benefit of minimizing hogging. Depth and width are related to
feed and depth of cut, so you more or less just have to experiment with the
combinations until you become familiar with them and how they behave under
certain circumstances. Does that make any sense?

Yes, that's correct, but it's a good idea to incorporate a chip breaker
as
your rake angle. It takes a little grinding experience to get good at
it,
but it really pays benefits. A simple rake angle improves machining
ability, but creates horrible chip problems. When you couple the chip
breaker with the rake angle, all that goes away. If nothing else, you
gain
considerable safety, not generating long strings that can wrap around
your
spinning object.

Heh, I know how much of a pain it is to have a wad of razor wire get
snagged by the chuck and spun around at a few hundred RPM!
How would I incorporate a chip breaker into the rake angle? My
wild-assed guess would be to grind a too-shallow rake angle across the
whole top of the tool, then the proper rake angle only about half way
back. That would make a little hump just behind the cutting edge. Any
photos on the web of grinding chip breakers?
And how would I judge the effectiveness of a chipbreaker? Should I
expect to produce a bunch of little uniform chips, or should I just
expect the string to snap off every so often?

Again, many things determine how well they work. You can expect perfect
chip breaking when the design fits the application. When your breaker is
too narrow, the chips may just ignore it, sliding across the top instead of
curling. That's not common. What usually happens is the breaker is too
narrow and deep for the cut, so chips stack up in it, which can lead to a
broken tool if you're not on your toes. When that happens, you widen the
groove, providing a more gentle arc so the chip can roll through without
stacking up. You can also take a lighter feed, but that's not the best way
to get where you're headed. As I said, chip breakers are very reliant on
the cut in order to perform properly. Often you'll start a cut with .008"
feed and the chips won't break, but increase to .012" and they break
perfectly. Without standing over your shoulder, it's pretty hard to
describe. Experience, even bad experience, will help you make sense of it.

Is diesel close enough to kerosene to work? I can get a little
container of diesel easy, but kerosene will be a hassle. I'm in texas,
so our diesel is as sulphury as law allows. (:

I own a couple Dodge diesels, and hate the smell of the fuel. I've
never
tried it, but I can't imagine it wouldn't work. I used Stoddard in
place
of kerosene to get away from the smell, which is similar to diesel. If
you have a (Stoddard) solvent container for cleaning parts, just dip a
little out as needed. I've done that for years. Sulfur is very much a
part
of lubricating when machining. One of the best oils for machining steel
is
sulfur based cutting oil. The stinky stuff.

Ah, my day-job is diesel equipment buffoonery & repair, so I'm quite
accustomed to the smell. Even kind of like it. (: That's why I can
get it easily--have a (cleaned out) mustard bottle full of it already.
I have no idea what's in the bottles of cutting oil in the machine
shop. Some are quite thick, some are thin, all have different smells,
most are the color of fresh motor oil, some are the color of used, one
looks like gear oil, but doesn't smell like it, and another I swear is
water. Probably some good oil somewhere in that collection.
If I can find some known good cutting oil I'll use that.

For aluminum, it's fairly safe to say that you should avoid any of the heavy
oils. Considering you don't mind the smell of diesel, I'd make that my
first attempt, but don't expect it to make a difference if you use the
negative rake inserts. I should have mentioned that, for the most part,
*because* of the false cutting edge that is expected when running negative
rake inserts, the tip, even on new ones, is usually not sharp. It need not
be, and is better off to not be. That's one of the chief reasons to avoid
using them on aluminum. They simply aren't sharp enough to cut well.
Aluminum responds to being "peeled", something not accomplished with
negative rake.

Steel on the lathe was always right on once I quit mixing up the
inch and metric dials, but aluminum (oddly enough!) was pretty much
unpredictable -- always somewhere between -1 and +4 thou.

While I'd be a fool to say I know why, my guess is that the insert you're
using isn't doing the cutting, but the built up edge is. The cut would be
ragged and change according to the amount of buildup present, which would
likely be constantly changing to some degree, affecting the diameter. The
finish would show exactly that, being a torn and ragged surface instead of a
shiny one.

There's nothing like a sharp tool when you're machining aluminum. It's
perfectly willing to machine freely and leave a decent finish, providing you
do your part and supply the proper tool and lubrication. Grade of
aluminum makes a difference too, as does the condition. Soft aluminum is a
bitch.. 7075, 6061 and 2024, all in an artificially aged condition,
(T-6, T651, T351, etc.) are all great to work with. Some grades are not
considered machining grades and cut poorly.

Harold

In article ,
"Harold and Susan Vordos" wrote:

[...]

Although I see the logic behind this, admittedly, I'd prefer at least
a couple of days on cutting physics. We are all going to make cutters
for threading, but that's not exactly the same thing as making a
generalized cutting tool.

In a sense, once you understand the geometry, it's all closely related.
Threading offers some challenges beyond normal turning because of the rapid
advance of the tool with coarse threads, so your side clearances have to be
modified. I gather you'll get to that eventually. I didn't realize your
class was not an introductory to machining, so I may have spoken out of
turn. Lets keep a watch and see what you're taught. Also, try to keep
in mind I'm an old school machinist, with absolutely no hands on with CNC
machinery. Many of the things that I hold dear and spelled success for me
may very well not be being taught now. However, for the guy with a manual
machine at home, knowing the things I learned spell total freedom.

I for one am deeply interested in learning the old-fashioned
(requiring intelligence) way of doing things. Even if I never do it
that way I usually notice my quality of work improving as a side-effect
of simply knowing more.

I saw elsewhere in the thread you were starting to wonder about my
teacher's competence. As far as I can tell he's quite skilled and so
far every question I've brought to him has been answered. I figure if I
start using HSS tooling instead of the inserts he'll hang around me and
point out all the important stuff. It's just that this is a basic class
And as a bit of trivia, he's still got Kenneth McDuff's old toolbox.
Apparently, Mr. Sadist took this same class before he got arrested.

I'm afraid you have me at a disadvantage. Kenneth McDuff? Doesn't ring
a bell.

Serial killer who prowled around Waco, TX a couple decades ago.
Executed in the late '90s, IIRC. Don't mess with Texas.

[...brevity...]

Steel on the lathe was always right on once I quit mixing up the
inch and metric dials, but aluminum (oddly enough!) was pretty much
unpredictable -- always somewhere between -1 and +4 thou.

While I'd be a fool to say I know why, my guess is that the insert you're
using isn't doing the cutting, but the built up edge is. The cut would be
ragged and change according to the amount of buildup present, which would
likely be constantly changing to some degree, affecting the diameter. The
finish would show exactly that, being a torn and ragged surface instead of a
shiny one.

There's nothing like a sharp tool when you're machining aluminum. It's
perfectly willing to machine freely and leave a decent finish, providing you
do your part and supply the proper tool and lubrication. Grade of
aluminum makes a difference too, as does the condition. Soft aluminum is a
bitch.. 7075, 6061 and 2024, all in an artificially aged condition,
(T-6, T651, T351, etc.) are all great to work with. Some grades are not
considered machining grades and cut poorly.

Class was again today. We had a test and a substitute, so it took
some smooth talking to get some machine time. Unfortunately, the good
mandrel was our teacher's private property and got locked in his box.
For good reason, too. Apparently someone threaded the shop's mandrel.
So, didn't get to mess with the flywheel, but I did make a cutter and
mess with some scrap aluminum. Wow, a whole lot better! For one, the
piece never got hot. Aluminum just flew right off even if I jammed the
cutter in. I didn't exactly mean to do that, but it turned out well
enough.
I didn't make a chip breaker, though. Even without it no matter what
I did I couldn't get strings. Depending on how much I cut I either just
scores of tiny flakes or sometimes little curls. Probably because my
tool is pointed and has no "nose" to it.
Rather than measure everything out and go for exact grinding I just
eyeballed it this first time around. I was also operating under the
assumption I could get the bit as hot as I could stand holding without
doing any damage. Got some blue and brown on it, but otherwise looks as
much like http://www.sherline.com/images/grndfg10.gif as I could
remember at the time. I intended to round off the sharp corner, but
wound up hosing that and had to grind the end of the tool back until I
had a point again. Using it like that I could rough out a piece in a
big hurry and just turn the feed way down for a final pass and get a
smooth finish the diameter I intend. Is there a trick to rounding that
corner, or is it just something to practice until I don't hose it?
Also, that lathe still had the two carbide holders sitting on it, but
this week they both have built up edges.

--
B.B. --I am not a goat! thegoat4 at airmail dot net
http://web2.airmail.net/thegoat4/

In article , B.B.
says...


Rather than measure everything out and go for exact grinding I just
eyeballed it this first time around. I was also operating under the
assumption I could get the bit as hot as I could stand holding without
doing any damage. Got some blue and brown on it, but otherwise looks as
much like http://www.sherline.com/images/grndfg10.gif as I could
remember at the time.

That one would work fine. You don't really need a chipbreaker for
what you are doing. I respect harold a lot but he's pretty
compulsive about doing things the 100% right way. For small depths
of cut you won't see any real detriment to not having a chipbreaker
except maybe the chip coming off will mark the finish to some
slight degree.

Try grinding a turning tool that is similar to the sherline one,
but don't put any back rake on it - use only three grinds to form
1) front clearance, 2) side rake, and 3) side clearance. It
will look like the one on the far right side of this photo:

http://www.metalworking.com/DropBox/_2000_retired_files/Tp3.jpg

and in that shot the tool would be cutting *away* from the viewer.

Another view of the same tool, where it would be cutting towards the
viewer and slightly to the right:

http://www.metalworking.com/DropBox/_2000_retired_files/Tp2.jpg

And the final view from underneath:

http://www.metalworking.com/DropBox/_2000_retired_files/Tp1.jpg

From the photos you can see it's pretty similar to your sherline
diagram, but the grind for the top surface is parallel to the long
axis of the tool, there's no 'back' angle. The edge thus formed
between the top surface and the side grind is nearly exactly along
the original edge of the side and top of the square cross-section
tool. What this means is you can resharpen this kind of tool
by simply grinding its *front* face, and the height of the
cutting edge does not change.

It's only three grinds on the HSS tool blank - if you do the
front, and side, but no top grind to form side rake, you've
made a brass turning tool.

I've found that back rake has never been essential for the stuff
I do, at work or at home. So I just leave it out.

If you *wanted* to form a chipbreaker in that kind of tool,
the idea would be to run a narrow groove alongside the cutting
edge, on the top surface. This allows the chips to flow off
at a larger angle than the real rake angle, and they eventually
strike the grooves far edge and snap.

When I took a shop class for the first time, there was an entire
four hour class period devoted to trying to get HSS tools ground
properly. Apparently in some classes the instructor simply
hands out 1/4 CRS blanks for the students to practice on.

One final caveat for you: pedestal grinders look pretty innocuous.
They're not. While you are grinding tool blanks by hand, the
blank will become hot, and your hand will become tired. You will
be applying a fair amount of pressure to the tool blank to force it
against the wheel.

The wheel will remove flesh faster than you can imagine - I personally
ground a pretty good-sized divot out of my thumb when I slipped
while grinding a lathe tool. Didn't bleed much at first but that
thing throbbed for weeks afterwards. Take your time and think
of the wheel surface the same way you would if you were grinding
your tool on the roadway, out of an open car door. I bet it's
about the same SFPM.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

In article ,
jim rozen wrote:

In article , B.B.
says...


Rather than measure everything out and go for exact grinding I just
eyeballed it this first time around. I was also operating under the
assumption I could get the bit as hot as I could stand holding without
doing any damage. Got some blue and brown on it, but otherwise looks as
much like http://www.sherline.com/images/grndfg10.gif as I could
remember at the time.

That one would work fine. You don't really need a chipbreaker for
what you are doing. I respect harold a lot but he's pretty
compulsive about doing things the 100% right way. For small depths
of cut you won't see any real detriment to not having a chipbreaker
except maybe the chip coming off will mark the finish to some
slight degree.

Good point. But somewhere along the line I'm going to try to force
the issue and find a cut that'll require a chip breaker, just so I have
a chance to play with the idea. I think perhaps steel would do it. So
far even with the carbides it's been more prone to looooong curls of
chip.
If you know a way to force long chips that would mandate a breaker
I'd like to know it too.

Try grinding a turning tool that is similar to the sherline one,
but don't put any back rake on it - use only three grinds to form
1) front clearance, 2) side rake, and 3) side clearance. It
will look like the one on the far right side of this photo:

http://www.metalworking.com/DropBox/_2000_retired_files/Tp3.jpg

and in that shot the tool would be cutting *away* from the viewer.

Another view of the same tool, where it would be cutting towards the
viewer and slightly to the right:

http://www.metalworking.com/DropBox/_2000_retired_files/Tp2.jpg

And the final view from underneath:

http://www.metalworking.com/DropBox/_2000_retired_files/Tp1.jpg

From the photos you can see it's pretty similar to your sherline
diagram, but the grind for the top surface is parallel to the long
axis of the tool, there's no 'back' angle. The edge thus formed
between the top surface and the side grind is nearly exactly along
the original edge of the side and top of the square cross-section
tool. What this means is you can resharpen this kind of tool
by simply grinding its *front* face, and the height of the
cutting edge does not change.

While I'm thinking of it...
As I understand things, if I do change the height of the cutting edge
the only real drawback is that I need to compensate and move the tool up
until it's level with the centerline. Correct? The lathe I've been
using has a quick-change post that lets me set the height, and I have a
feeler gauge set that's unreadable now, but would make dandy shims if
I'm ever using a non-adjustable tool holder.

It's only three grinds on the HSS tool blank - if you do the
front, and side, but no top grind to form side rake, you've
made a brass turning tool.

Cool! I'll grind the other end of my tool that way and see how it
works out since I have to redo a brass bushing.
Why a flat top on a brass tool? To keep it from pulling itself in?
Are there other materials that would want zero side rake? Is there
perhaps a list somewhere of common materials and appropriate cutter
geometry?

I've found that back rake has never been essential for the stuff
I do, at work or at home. So I just leave it out.

If you *wanted* to form a chipbreaker in that kind of tool,
the idea would be to run a narrow groove alongside the cutting
edge, on the top surface. This allows the chips to flow off
at a larger angle than the real rake angle, and they eventually
strike the grooves far edge and snap.

Is there a standard distance back I should go, or just look and see
where the chips are hitting the top of the tool and put it there?

When I took a shop class for the first time, there was an entire
four hour class period devoted to trying to get HSS tools ground
properly. Apparently in some classes the instructor simply
hands out 1/4 CRS blanks for the students to practice on.

One final caveat for you: pedestal grinders look pretty innocuous.
They're not. While you are grinding tool blanks by hand, the
blank will become hot, and your hand will become tired. You will
be applying a fair amount of pressure to the tool blank to force it
against the wheel.

The wheel will remove flesh faster than you can imagine - I personally
ground a pretty good-sized divot out of my thumb when I slipped
while grinding a lathe tool. Didn't bleed much at first but that
thing throbbed for weeks afterwards. Take your time and think
of the wheel surface the same way you would if you were grinding
your tool on the roadway, out of an open car door. I bet it's
about the same SFPM.

I've had my share of grinder mishaps. My personal best--or worst--is
getting a bolt I was grinding a flat onto get pulled between the
grinding wheel and rest, taking my finger with it. It finally took
enough flesh off the side of one finger that I could slide my hand out
sideways without getting snagged again. Imagination be damned! I have
first-hand (heh) experience! Whole thing took maybe two seconds. Since
then I've had lots and lots of respect for even wee little grinders. If
the rest has a gap big enough for my finger I either adjust the rest,
remove it entirely, or find another grinder.
Seems that accident only took skin--healed up fine and really doesn't
stand out above the other 5 billion scars my hands sport.
My second-best experience was grinding something, shutting off the
wheel, and having it explode after I got about five feet away. That one
had a vibration somewhere below operating speed, so my guess is that the
wheel popped when it hit that speed/vibration/harmonic while winding
down. So now I also stand clear while the wheels are spinning up and
spinning down and won't touch (or walk past) a machine that shakes while
running. While I grind I tend to keep my head to the side a bit--just
in case.

--
B.B. --I am not a goat! thegoat4 at airmail dot net
http://web2.airmail.net/thegoat4/

"B.B." u wrote in message
news
In article ,
jim rozen wrote:

In article ,
B.B.
says...


Rather than measure everything out and go for exact grinding I just
eyeballed it this first time around. I was also operating under the
assumption I could get the bit as hot as I could stand holding without
doing any damage. Got some blue and brown on it, but otherwise looks as
much like http://www.sherline.com/images/grndfg10.gif as I could
remember at the time.

That one would work fine. You don't really need a chipbreaker for
what you are doing. I respect harold a lot but he's pretty
compulsive about doing things the 100% right way. For small depths
of cut you won't see any real detriment to not having a chipbreaker
except maybe the chip coming off will mark the finish to some
slight degree.

True on all accounts. The problem here is if you wait until you actually
need a proper chip breaker, you've missed a golden opportunity to get it
straight, from the start.

Chip breakers, once again, are load sensitive. Jim is right on the money.
A chip breaker that works beautifully for a roughing cut is likely to fall
flat on its face when taking finish cuts. At best, you'd profit by the
positive rake, but not much else. That's not a problem when you're running
parts in volume, because you generally go through a roughing sequence before
any of the parts get finished. That, too, is a part of learning to machine
properly. Your tools are ground and setup appropriately. My point in
getting you to try chip breakers is to learn about them and have them firmly
entrenched in your mind, so when the need arises you don't have to go
through the learning curve.


Good point. But somewhere along the line I'm going to try to force
the issue and find a cut that'll require a chip breaker, just so I have
a chance to play with the idea. I think perhaps steel would do it. So
far even with the carbides it's been more prone to looooong curls of
chip.
If you know a way to force long chips that would mandate a breaker
I'd like to know it too.

Simple. Proper positive rake. Light feed. No chip breaker. You can
generate all the strings you desire. That's the point of my information.
The use of chip breakers is a package deal. Lots of things have to come
together.

Understand that some aluminums cut without making strings. It's the nature
of the material. Amongst them are 2024 and 7075, each of which will gladly
cut string free under the right conditions, including the absence of a
proper chip breaker. 6061 is another story, and is generally more than
happy to generate strings, although generally very easy to control.


snip-

While I'm thinking of it...
As I understand things, if I do change the height of the cutting edge
the only real drawback is that I need to compensate and move the tool up
until it's level with the centerline. Correct?

Regardless of the holding system, that's an ongoing problem. I use a
square tool block (my choice) so I shim all my tools. You get used to
having a small box of shims handy and it takes almost no time to set up your
tools. You get to the point where you can pick up a tool and know what shim
is required to hit center. I use anything for shims, including strapping
material, which comes in a myriad of thicknesses. Old feeler gages are
fine, too, just expensive. And then there's always shim stock!

I've found that back rake has never been essential for the stuff
I do, at work or at home. So I just leave it out.

You can go full circle on this issue and stick to making finishing cuts with
chip welded negative rake inserts. I strongly recommend you *don't* avoid
the learning curve. Learn to do it right, even when it takes more time.
You can always back off when it's not important, but without the experience,
you'll have nothing to use as a reference when you're facing problems.
The real benefit of learning the little things is when a tough job comes
along, you may be the only one equipped to deal with it. I gained the
respect of my peers because of my anal approach to machining. No one
wanted to emulate what I did, but they sure as hell understood why I had
success when they did not. Remember, often the difference between one who
can and one who can't is nothing more than how they apply what they know.
You see that on a daily basis in a commercial shop.


If you *wanted* to form a chipbreaker in that kind of tool,
the idea would be to run a narrow groove alongside the cutting
edge, on the top surface. This allows the chips to flow off
at a larger angle than the real rake angle, and they eventually
strike the grooves far edge and snap.

That's too simplified, and may or may not work. If you look at chip
breakers that are formed on negative rake inserts, you'll notice they are a
shallow radius which begins at the theoretical false cutting edge of the
insert. It's assumed you're going to take a particular depth of cut and a
given amount of feed, so they factor that in when creating the inserts.
The whole idea is to encourage the chip to start rolling, not to stub into a
wall. That raises cutting pressure, often breaking your tool from chip
stalk up.

A chip breaker that doesn't function has no value. Be certain to learn to
incorporate rake when you attempt chip breakers. It's particularly
important when using HSS, so you can keep temperatures low at the cut, and
reduce cutting pressure as well.

There's no shortcut, you have to start at the bottom and experiment with
each material, slowly accumulating enough information in your head that it
will become useful. You'll know when you've hit a winner. The chips curl
and break nicely, and the tool cuts without much noise. Watch the chip
color (when machining steel) so you don't produce anything above the
slightest hint of yellow. That usually spells an early death for your tool
unless you have very high cobalt, or are lucky enough to be using Stellite.
Tools of this nature generally respond very well to lubrication, too. Helps
keep the temperature down and prolong the tool's life.

Is there a standard distance back I should go, or just look and see
where the chips are hitting the top of the tool and put it there?

My policy is to grind the breaker and take a trial cut. Again, the cut
required determines everything. Maybe start short and shallow and see how
it behaves. You can always go wider and deeper, but can't reverse the
process without wasting a good amount of tool. Once you see what the chip's
doing, you can make the appropriate adjustment. This process can really
pay benefits when you're boring deep holes. With the proper tool
configuration, you can go deep and not generate any strings, which generally
spell tool death when they wrap around the bar. If your bar has enough
clearance, your chips will come out as short crumbles and drop neatly at the
mouth of your part. Lots depends on bar clearance, but I think you get
the idea.

When I took a shop class for the first time, there was an entire
four hour class period devoted to trying to get HSS tools ground
properly. Apparently in some classes the instructor simply
hands out 1/4 CRS blanks for the students to practice on.

To start, that's not a bad idea. The only real problem is the CRS doesn't
grind worth a damn. The concept remains unchanged, though.

One thing I don't use is a tool rest. Never. Not for grinding tool bits.
They get in the way and restrict your ability. You likely won't be able to
do that at school, but keep it in mind for home use. Have a special grinder
that you use exclusively for sharpening toolbits, and have it mounted such
that you can stand erect and grind at a comfortable level. It takes some
getting used to, but once you master it, you'll never go back to a
conventional pedestal grinder for grinding toolbits. Knowing how to
properly dress the wheel becomes quite important when you grind this way.
It must run smooth and true, for it becomes your reference point.

Harold

In article , Harold and Susan Vordos says...

My point in
getting you to try chip breakers is to learn about them and have them firmly
entrenched in your mind, so when the need arises you don't have to go
through the learning curve.

Something I never did. LOL. Might be time to investigate, eh?
I seem to recall teenut saying something about the chipbreaker
groove on a HSS tool could be done with a tiny cutoff wheel
and a die grinder.


Understand that some aluminums cut without making strings. It's the nature
of the material. Amongst them are 2024 and 7075, each of which will gladly
cut string free under the right conditions, including the absence of a
proper chip breaker. 6061 is another story, and is generally more than
happy to generate strings, although generally very easy to control.

6061 is like turning silly putty. 2024T6 is more like steel than
aluminum. I love that stuff. Too bad you can't weld it.

... I use a
square tool block (my choice) so I shim all my tools. You get used to
having a small box of shims handy and it takes almost no time to set up your
tools. You get to the point where you can pick up a tool and know what shim
is required to hit center. I use anything for shims, including strapping
material, which comes in a myriad of thicknesses. Old feeler gages are
fine, too, just expensive. And then there's always shim stock!

This is one reason I avoid back rake - because it means that sharpening
the tool requires resetting center height.

One thing I don't use is a tool rest. Never. Not for grinding tool bits.
They get in the way and restrict your ability. You likely won't be able to
do that at school, but keep it in mind for home use. Have a special grinder
that you use exclusively for sharpening toolbits, and have it mounted such
that you can stand erect and grind at a comfortable level. It takes some
getting used to, but once you master it, you'll never go back to a
conventional pedestal grinder for grinding toolbits. Knowing how to
properly dress the wheel becomes quite important when you grind this way.
It must run smooth and true, for it becomes your reference point.

Toolrests are OK for roughing stuff out, but I agree that 90 percent
of the lathe tool grinding I do is offhand, no rest. You have to be
able to get the angles right. Good lighting is vital. My grinder
is tucked away in a far corner of my shop, to keep grit off the machines.
The lighting sucks there, it's one more of those roundtuit items.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

In article , B.B.
says...

While I'm thinking of it...
As I understand things, if I do change the height of the cutting edge
the only real drawback is that I need to compensate and move the tool up
until it's level with the centerline. Correct? The lathe I've been
using has a quick-change post that lets me set the height, and I have a
feeler gauge set that's unreadable now, but would make dandy shims if
I'm ever using a non-adjustable tool holder.

As harold said, basically "yes." If you have an aloris or other
import QC toolholder you don't have to worry about shims. Eventually
you will wind up with a non-adjustable one and have to worry about
it. Just face off a piece of stock in the spindle, and that will
tell you if you are are high or low. If low it will leave a pip
there, if high the tool simply won't cut well when you get down
to the center. You should understand the relationship between
center height, front clearance, and rake.

If you are a bit high, the rake goes more postive, but the clearance
goes away. If low, the clearance increases but the rake becomes
more negative. When boring or facing this can be used to some
advantage.

It's only three grinds on the HSS tool blank - if you do the
front, and side, but no top grind to form side rake, you've
made a brass turning tool.

Cool! I'll grind the other end of my tool that way and see how it
works out since I have to redo a brass bushing.
Why a flat top on a brass tool? To keep it from pulling itself in?
Are there other materials that would want zero side rake? Is there
perhaps a list somewhere of common materials and appropriate cutter
geometry?

Brass cutting tools really want to have zero rake. But if you think
about it, threading tools and cutoff tools also are run with pretty
much zero rake. If you notice in one of those photos of that small
toolblock above, I have a grooving tool in there, that looks like a
tiny cutoff tool. It works great in steel even though it has *zero*
rake. Key is to keep the tool engagement in the workpiece to a
minimum.

Drilling brass with twist drills meant for steel can cause all kinds of
excitement. The cutting edge is flatted off to make them zero rake
and then the problem goes away.

I've had my share of grinder mishaps. My personal best--or worst--is
getting a bolt I was grinding a flat onto get pulled between the
grinding wheel and rest, taking my finger with it. It finally took
enough flesh off the side of one finger that I could slide my hand out
sideways without getting snagged again. Imagination be damned! I have
first-hand (heh) experience! Whole thing took maybe two seconds. Since
then I've had lots and lots of respect for even wee little grinders. If
the rest has a gap big enough for my finger I either adjust the rest,
remove it entirely, or find another grinder.

This is an OSHA requirment now. Grinders *must* have the rest within
1/16 or so, and they like to see a seconary stop at the top of the
guard as well, so if something gets in there, it won't get spit out
back into the operator. Don't use a machine where the rest is
far away from the wheel.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

"jim rozen" wrote in message
...
In article , Harold and Susan Vordos says...

My point in
getting you to try chip breakers is to learn about them and have them
firmly
entrenched in your mind, so when the need arises you don't have to go
through the learning curve.

Something I never did. LOL. Might be time to investigate, eh?

It's one of those things that you can go a life time without and swear it
makes no difference.. Bottom line is how much you expect from your machine,
your setup, your ability. I've always carried a definite edge over others
because I cared enough to learn early on. You're likely to find someone
that has the opinion that it doesn't matter. I think it does. I may
sound like an ass, but I can tell you all I need to know about a guy's
ability on a machine by looking at his lathe tools. When they look like
they've been gnawed out by a gopher, I rarely expect anything of substance
to come from the person, and I'm rarely disappointed.


I seem to recall teenut saying something about the chipbreaker
groove on a HSS tool could be done with a tiny cutoff wheel
and a die grinder.


I don't claim to be teenut, but I sure agree with him in this instance.
However, I don't limit myself to that. I can hand grind the vast majority
of my chip breakers using the corner of the wheel. Only when I get involved
with tricky form tools do I usually turn to anything else.


Understand that some aluminums cut without making strings. It's the
nature
of the material. Amongst them are 2024 and 7075, each of which will
gladly
cut string free under the right conditions, including the absence of a
proper chip breaker. 6061 is another story, and is generally more than
happy to generate strings, although generally very easy to control.

6061 is like turning silly putty. 2024T6 is more like steel than
aluminum. I love that stuff. Too bad you can't weld it.

It is a pleasure. During the period that we built the missile, and shortly
thereafter, it was the only choice of aircraft quality material we used. My
first introduction to 7075 was when I had already started my business and
had bid on some helmet gun sights for helicopters. Needless to say, I was
impressed. While you claim 2024 machines like steel, 7075 really does,
and emulates it in tensile strength. I liken it to leaded steel in how it
machines.

One of my favorite memories of being self employed was building a wave guide
for Univac. They never came in large quantities, sometimes as many as four
or five, but more often than not, one at a time. They were made from 2024
T351, a real pleasure to machine. Inside the guide a double ended plastic
component that came to a .005" flat end (wedge shaped) was installed, held
in place by four pins, also made of the same plastic. The job brought out
the best of my ability, with it's tight tolerance and exacting demands for
generating the proper configuration of the plastic insert.


... I use a
square tool block (my choice) so I shim all my tools. You get used to
having a small box of shims handy and it takes almost no time to set up
your
tools. You get to the point where you can pick up a tool and know what
shim
is required to hit center. I use anything for shims, including
strapping
material, which comes in a myriad of thicknesses. Old feeler gages are
fine, too, just expensive. And then there's always shim stock!

This is one reason I avoid back rake - because it means that sharpening
the tool requires resetting center height.

Not a very good reason, Jim. I'm the first to step forward and suggest
that you can machine with or without rake, with or without a chip breaker,
but the best work comes from the proper combination of each. It really
jumps out at you when you have more than a couple parts to make. You've
done yourself a disservice, something you'll slowly come to understand. I
guarantee you, your tools don't cut nearly as well as they can. Chip
control is as important as chip generating.

One thing I don't use is a tool rest. Never. Not for grinding tool bits.
They get in the way and restrict your ability. You likely won't be able
to
do that at school, but keep it in mind for home use. Have a special
grinder
that you use exclusively for sharpening toolbits, and have it mounted
such
that you can stand erect and grind at a comfortable level. It takes
some
getting used to, but once you master it, you'll never go back to a
conventional pedestal grinder for grinding toolbits. Knowing how to
properly dress the wheel becomes quite important when you grind this way.
It must run smooth and true, for it becomes your reference point.

Toolrests are OK for roughing stuff out, but I agree that 90 percent
of the lathe tool grinding I do is offhand, no rest. You have to be
able to get the angles right. Good lighting is vital. My grinder
is tucked away in a far corner of my shop, to keep grit off the machines.
The lighting sucks there, it's one more of those roundtuit items.

Jim

Chuckle! All in good time, eh Jim? Just don't let your entire life time
slip away, putting up with the bad setup as it is. It's almost impossible
for me to properly sharpen tools right now, what with our living in the
shop. My (rough) grinding section , roughly 30 feet from my precision
machines, happens to be the cloths drying station while we're living here,
so my grinder isn't properly set up. Of all the things I can't use as
desired, I miss it more than any of them. Especially the diamond wheel,
for touching up brazed carbide tools. I'm still a strong believer in them.
Old habits die hard.

Harold

In article , Harold and Susan Vordos says...

It's one of those things that you can go a life time without and swear it
makes no difference.. Bottom line is how much you expect from your machine,
your setup, your ability. I've always carried a definite edge over others
because I cared enough to learn early on. You're likely to find someone
that has the opinion that it doesn't matter. I think it does. I may
sound like an ass, but I can tell you all I need to know about a guy's
ability on a machine by looking at his lathe tools. When they look like
they've been gnawed out by a gopher, I rarely expect anything of substance
to come from the person, and I'm rarely disappointed.

Ah Haa! So this is why you don't like insert tools - you can't
use that as a metric any more! :^)

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

conventional pedestal grinder for grinding toolbits. Knowing how to
properly dress the wheel becomes quite important when you grind this way.
It must run smooth and true, for it becomes your reference point.

OK. Maybe you guys can tell me how to dress a new 10 inch grinding wheel!

I have a baldor 10 inch grinder and I installed new name brand wheels
from MSC. I have two different wheel dressors (0-10) (10+) and I still
cannot get the wheels round. I even tried using a diamond point and ruined it.

So, How do you dress a new 10 inch grinding wheel ??

chuck