I've been pondering the issues of clamping and holding work on a mill
table and I'm really not encouraged. The difficulty in securely
holding the material and yet leaving an empty space around it where
you plan to be cutting it, while still maintaining precise alignment,
seems like a really big headache for any small, thin, or irregularly
shaped (or curved) items. I think I'd need to have a $300 stack of
chopped up parallels and a half-dozen customized sets of vise-jaws to
even begin. Either that or resign myself to adding several unnecessary
threaded holes in each part -- just to hold them down. Am I
exaggerating the difficulty level?

Thanks,

Dave

On Wed, 01 Sep 2004 22:49:37 -0700, Dave wrote:

I've been pondering the issues of clamping and holding work on a mill
table and I'm really not encouraged. The difficulty in securely
holding the material and yet leaving an empty space around it where
you plan to be cutting it, while still maintaining precise alignment,
seems like a really big headache for any small, thin, or irregularly
shaped (or curved) items. I think I'd need to have a $300 stack of
chopped up parallels and a half-dozen customized sets of vise-jaws to
even begin. Either that or resign myself to adding several unnecessary
threaded holes in each part -- just to hold them down. Am I
exaggerating the difficulty level?

I didn't need much more than a good sturdy milling vise to get me
started. You can make lots of clamps, jigs, and other work-holding
fixtures in a good vise. Parallels are a vital tool to have when
working with a milling vise, but since I have a bunch of square HSS
toolbits of different sizes I haven't needed to go and buy parallels
yet. I just stack some up under the work and I'm good to go. I just
made a pair of V blocks for a project I'm working on (a plate bender).
Since they're only made of mild steel I can't harden them, and even if
I could I can't finish grind them, but oh well, they'll suffice for
this project (milling a 3" long flat half way through a 2" diam.
carbon steel bar) and maybe a few others.

Probably the most challenging thing about using a miller is figuring
out how to set jobs up. As you find a need for a special item you can
buy it and add it to your collection, much like people do with drill
bits - purchasing only the ones they use often and not wasting money
on whole sets where half of the bits never see a chuck.

Artemia Salina wrote:

On Wed, 01 Sep 2004 22:49:37 -0700, Dave wrote:


I've been pondering the issues of clamping and holding work on a mill
table and I'm really not encouraged. The difficulty in securely
holding the material and yet leaving an empty space around it where
you plan to be cutting it, while still maintaining precise alignment,
seems like a really big headache for any small, thin, or irregularly
shaped (or curved) items. I think I'd need to have a $300 stack of
chopped up parallels and a half-dozen customized sets of vise-jaws to
even begin. Either that or resign myself to adding several unnecessary
threaded holes in each part -- just to hold them down. Am I
exaggerating the difficulty level?


I didn't need much more than a good sturdy milling vise to get me
started. You can make lots of clamps, jigs, and other work-holding
fixtures in a good vise. Parallels are a vital tool to have when
working with a milling vise, but since I have a bunch of square HSS
toolbits of different sizes I haven't needed to go and buy parallels
yet. I just stack some up under the work and I'm good to go. I just
made a pair of V blocks for a project I'm working on (a plate bender).
Since they're only made of mild steel I can't harden them, and even if
I could I can't finish grind them, but oh well, they'll suffice for
this project (milling a 3" long flat half way through a 2" diam.
carbon steel bar) and maybe a few others.

Probably the most challenging thing about using a miller is figuring
out how to set jobs up. As you find a need for a special item you can
buy it and add it to your collection, much like people do with drill
bits - purchasing only the ones they use often and not wasting money
on whole sets where half of the bits never see a chuck.


You're certainly correct. Workholding is half the challenge. Its deeper
even than this; design of good fixtures was what they did before CNC
milling, and it still works pretty good for manual milling.

I would say my short list is:

1. Vice.

2. Vice with parallels.

3. Clamps.

4. Side clamps, those clamps that hold the part at the base like
powerful fingers.

5. "pot it", or use low melting temperature metal to hold it.

6. Bolt or screw the workpiece to a plate.

For REALLY odd shaped workpieces, 6 cannot be beat. You get some
extra screw holes - big deal. The part is held to a plate with
complete access to all sides save the one face down. With most
parts, it hardly matters if there is an extra screw hole, and
if it does, it can be filled by various means.

--
Samiam is Scott A. Moore

Personal web site: http:/www.moorecad.com/scott
My electronics engineering consulting site: http://www.moorecad.com
ISO 7185 Standard Pascal web site: http://www.moorecad.com/standardpascal
Classic Basic Games web site: http://www.moorecad.com/classicbasic
The IP Pascal web site, a high performance, highly portable ISO 7185 Pascal
compiler system: http://www.moorecad.com/ippas

Being right is more powerfull than large corporations or governments.
The right argument may not be pervasive, but the facts eventually are.

"Scott Moore" wrote in message
news:rOHZc.277598$eM2.258836@attbi_s51...
snip-----

You get some
extra screw holes - big deal. The part is held to a plate with
complete access to all sides save the one face down. With most
parts, it hardly matters if there is an extra screw hole, and
if it does, it can be filled by various means.

--
Samiam is Scott A. Moore

Chuckle!

Apparently you've never worked where parts are built to specs. An extra
hole is called scrap.

Harold

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

"
Chuckle!

Apparently you've never worked where parts are built to specs. An extra
hole is called scrap.

Harold

Gee Harold , I guess that you've never kept a farm rig running ;-)
lg
no neat sig line

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

Apparently you've never worked where parts are built to specs. An extra
hole is called scrap.

I know, can you believe that at the last place I worked, they used just
tossed all those extra holes away! Don't tell, but I made off with a
large bin full. I pretty well set up with holes for a while but it you
need some, let me know. I've got diameters from about #30 up to 3/4" and
the shipping is cheap!

Greg

PS. How many holes does it take to fill the Albert Hall?

In article ,
says...

"Scott Moore" wrote in message
news:rOHZc.277598$eM2.258836@attbi_s51...
snip-----

You get some
extra screw holes - big deal. The part is held to a plate with
complete access to all sides save the one face down. With most
parts, it hardly matters if there is an extra screw hole, and
if it does, it can be filled by various means.

--
Samiam is Scott A. Moore

Chuckle!

Apparently you've never worked where parts are built to specs. An extra
hole is called scrap.


Then I better not mention welding the part to a piece
that's convenient to hold. G Works great for turning
discs or rings from plate in the lathe.

Ned Simmons

"Ned Simmons" wrote in message
...
In article ,
says...

"Scott Moore" wrote in message
news:rOHZc.277598$eM2.258836@attbi_s51...
snip-----

You get some
extra screw holes - big deal. The part is held to a plate with
complete access to all sides save the one face down. With most
parts, it hardly matters if there is an extra screw hole, and
if it does, it can be filled by various means.

--
Samiam is Scott A. Moore

Chuckle!

Apparently you've never worked where parts are built to specs. An
extra
hole is called scrap.


Then I better not mention welding the part to a piece
that's convenient to hold. G Works great for turning
discs or rings from plate in the lathe.

Ned Simmons

Aaarrggghhh! Welding? On parts for the aero-space industry? Man,
you and Larry G. g

Where I came from, something as small as an improperly deburred edge was
rejected. You weld on a part, it's automatically scrap unless you see a
requirement for welding included on the print. I guess it's all to do with
the industry that you serve.

Harold

Scott Moore wrote:




You're certainly correct. Workholding is half the challenge. Its deeper
even than this; design of good fixtures was what they did before CNC
milling, and it still works pretty good for manual milling.

The design of good fixtures for CNC work is often the difference between
a "good" job, and a loser. Trust me on this, it's what I do.


I would say my short list is:

1. Vice.

2. Vice with parallels.

For the OP, get some .25 x 1.75 aluminum rec bar stock and cut a bunch
of 6" pieces. Cut a few pairs around 9' or so, also. Then you can make
whatever height parallel you need, as required. You can even drill or
mill into them without trashing your cutting tool. Some curved or bent
spring steel or thinnish brass works nicely to keep said parallels in
place.


I could go on and on, but I gotta lot of work to do.


michael


3. Clamps.

4. Side clamps, those clamps that hold the part at the base like
powerful fingers.

5. "pot it", or use low melting temperature metal to hold it.

6. Bolt or screw the workpiece to a plate.

For REALLY odd shaped workpieces, 6 cannot be beat. You get some
extra screw holes - big deal. The part is held to a plate with
complete access to all sides save the one face down. With most
parts, it hardly matters if there is an extra screw hole, and
if it does, it can be filled by various means.

--
Samiam is Scott A. Moore

Personal web site: http:/www.moorecad.com/scott
My electronics engineering consulting site: http://www.moorecad.com
ISO 7185 Standard Pascal web site: http://www.moorecad.com/standardpascal
Classic Basic Games web site: http://www.moorecad.com/classicbasic
The IP Pascal web site, a high performance, highly portable ISO 7185 Pascal
compiler system: http://www.moorecad.com/ippas

Being right is more powerfull than large corporations or governments.
The right argument may not be pervasive, but the facts eventually are.

"Dave" wrote in message
om...
I've been pondering the issues of clamping and holding work on a mill
table and I'm really not encouraged. The difficulty in securely
holding the material and yet leaving an empty space around it where
you plan to be cutting it, while still maintaining precise alignment,
seems like a really big headache for any small, thin, or irregularly
shaped (or curved) items. I think I'd need to have a $300 stack of
chopped up parallels and a half-dozen customized sets of vise-jaws to
even begin. Either that or resign myself to adding several unnecessary
threaded holes in each part -- just to hold them down. Am I
exaggerating the difficulty level?

Thanks,

Dave


Dave,

for small irregularly shaped items I use a low melt alloy (Cerrobend) - it
melts in boiling water and can be poured round the item locking it into a
frame that can be clamped. Works a treat and the alloy is infinately
re-useable.

Andrew Mawson

Andrew Mawson wrote:
for small irregularly shaped items I use a low melt alloy (Cerrobend) ...

What is a useful amount of Cerrobond? At $35/lb (IIRC), I don't want to
buy more than I'll need. Or less. Bob

"Bob Engelhardt" wrote in message
...
Andrew Mawson wrote:
for small irregularly shaped items I use a low melt alloy (Cerrobend)
....

What is a useful amount of Cerrobond? At $35/lb (IIRC), I don't want to
buy more than I'll need. Or less. Bob

I have 3 KGs that I use.

Andrew Mawson

Bob Engelhardt wrote:

Andrew Mawson wrote:
for small irregularly shaped items I use a low melt alloy (Cerrobend) ...

What is a useful amount of Cerrobond? At $35/lb (IIRC), I don't want to
buy more than I'll need. Or less. Bob

I don't know where I got the idea that Cerrobend was so expensive. I
just bought 5 lb. on eBay for $49 including shipping. They are 1 1/2+
lb ingots for $14 each. I suspect that he will sell direct:
Steven Kaplan

Bob

Hey Andrew:

I think the crux of this hobby, for many, is the creative parts. I've been
working metal for just several years, not a lifetime. I've never had the
pleasure of working on a Bridgeport, or a heavier mill. I have amassed
clamps, vises and parallels, because I apparantly have not seen a set of
parallels at auction that I didn't want to buy - for example.

I think your question is a good one, as it does get the creative juices
flowing. But with my simple gear - and a rotary table (import) - the
solutions usually offer themselves up after some study.

I think too, that we all get pulled into the overthinking trap.

I've been trying to figure out a way to tell if my garage door is open. I
ran a remote switch to the house (can't get to the attached garage from
inside) with 4-conductor wire. So, I'm pondering a way to utilize the other
pair for some light or something. My good friend comes by and I miserate
about the alternatives. He says, "why not put a mirror on the tree out
front?"

Why not indeed.

"Andrew Mawson" wrote in message
...

"Dave" wrote in message
om...
I've been pondering the issues of clamping and holding work on a mill
table and I'm really not encouraged. The difficulty in securely
holding the material and yet leaving an empty space around it where
you plan to be cutting it, while still maintaining precise alignment,
seems like a really big headache for any small, thin, or irregularly
shaped (or curved) items. I think I'd need to have a $300 stack of
chopped up parallels and a half-dozen customized sets of vise-jaws to
even begin. Either that or resign myself to adding several unnecessary
threaded holes in each part -- just to hold them down. Am I
exaggerating the difficulty level?

Thanks,

Dave


Dave,

for small irregularly shaped items I use a low melt alloy (Cerrobend) - it
melts in boiling water and can be poured round the item locking it into a
frame that can be clamped. Works a treat and the alloy is infinately
re-useable.

Andrew Mawson

"John Hofstad-Parkhill" wrote in message
...
Hey Andrew:

I think the crux of this hobby, for many, is the creative parts. I've been
working metal for just several years, not a lifetime. I've never had the
pleasure of working on a Bridgeport, or a heavier mill. I have amassed
clamps, vises and parallels, because I apparantly have not seen a set of
parallels at auction that I didn't want to buy - for example.

I think your question is a good one, as it does get the creative juices
flowing. But with my simple gear - and a rotary table (import) - the
solutions usually offer themselves up after some study.

I think too, that we all get pulled into the overthinking trap.

I've been trying to figure out a way to tell if my garage door is open. I
ran a remote switch to the house (can't get to the attached garage from
inside) with 4-conductor wire. So, I'm pondering a way to utilize the
other
pair for some light or something. My good friend comes by and I miserate
about the alternatives. He says, "why not put a mirror on the tree out
front?"

Why not indeed.

"Andrew Mawson" wrote in message
...

"Dave" wrote in message
om...
I've been pondering the issues of clamping and holding work on a mill
table and I'm really not encouraged. The difficulty in securely
holding the material and yet leaving an empty space around it where
you plan to be cutting it, while still maintaining precise alignment,
seems like a really big headache for any small, thin, or irregularly
shaped (or curved) items. I think I'd need to have a $300 stack of
chopped up parallels and a half-dozen customized sets of vise-jaws to
even begin. Either that or resign myself to adding several unnecessary
threaded holes in each part -- just to hold them down. Am I
exaggerating the difficulty level?

Thanks,

Dave


Dave,

for small irregularly shaped items I use a low melt alloy (Cerrobend) -
it
melts in boiling water and can be poured round the item locking it into
a
frame that can be clamped. Works a treat and the alloy is infinately
re-useable.

Andrew Mawson






.... er .... John I think you mixed up questions and answers here - mine was
an answer !!!!!!!

Andrew

Right you are Andrew.

To the original poster, stop worrying. You might mill for years before
you come to a setup you can't do. Most stuff you can do in a vise.
What you can't you can usually clamp to the table. When I get an
oddball profile that isn't critical I just stick the part in the
vise, mill off a little, turn it some, mill some more, and like
that, ending up with a piecewise linear approximation just outside
of the layout line, then I freehand sand to the line. I've made some
pretty stuff that way.

Watch the machining mags. Some of the guys writing in there come up with
some great ideas.

Grant

"Dave" wrote in message
om...
I've been pondering the issues of clamping and holding work on a mill
table and I'm really not encouraged. The difficulty in securely
holding the material and yet leaving an empty space around it where
you plan to be cutting it, while still maintaining precise alignment,
seems like a really big headache for any small, thin, or irregularly
shaped (or curved) items. I think I'd need to have a $300 stack of
chopped up parallels and a half-dozen customized sets of vise-jaws to
even begin. Either that or resign myself to adding several unnecessary
threaded holes in each part -- just to hold them down. Am I
exaggerating the difficulty level?

Thanks,

Dave

Hi Dave,
Another way to hold stuff is to make an extra table, from 1
inch thick plate. You can drill and tap holes in it to secure pieces. Also,
drill and ream holes for ground pins for alignment. So, say you need to mill
a rectangular workpiece on all edges, you set it against some pins and clamp
it down so it hangs just off the corner of the plate. Mill the exposed to
edges, then turn the work piece around so the other two edges are hanging
off the table and mill those, the pins keep everything square. If you bolt
some tangs to the underside and mill them accurately to the width of your
main table slots, and mill around the edge of the extra table while you are
at it, it will self align on the main table.

regards,

John

Dave wrote in message
om...
I've been pondering the issues of clamping and holding work on a mill
table and I'm really not encouraged. The difficulty in securely
holding the material and yet leaving an empty space around it where
you plan to be cutting it, while still maintaining precise alignment,
seems like a really big headache for any small, thin, or irregularly
shaped (or curved) items. I think I'd need to have a $300 stack of
chopped up parallels and a half-dozen customized sets of vise-jaws to
even begin. Either that or resign myself to adding several unnecessary
threaded holes in each part -- just to hold them down. Am I
exaggerating the difficulty level?


Jewellers use a vise that has a pair of plates with holes in 'em. The put
steel pins in the holes, the work between the pins, then they screw the
plates closer together. For really irrgular shapes something like that
might work; take light cuts.

That's neat! I'll be using that one! Might want a left-hand
endmill so the mill pushes the work down rather than trying to lift
it.

On Thu, 2 Sep 2004 09:07:01 -0300, "jtaylor"
wrote


Jewellers use a vise that has a pair of plates with holes in 'em. The put
steel pins in the holes, the work between the pins, then they screw the
plates closer together. For really irrgular shapes something like that
might work; take light cuts.

Don Foreman wrote:
That's neat! I'll be using that one! Might want a left-hand
endmill so the mill pushes the work down rather than trying to lift
it.

Any endmill will pull if you are cutting with the end face using the
correct direction of rotation. Did you mean using a left-hand endmill
against it's normal rotational direction? You could also do this with a
standard mill using reverse (if your machine has it). Either way it
doesn't cut so well and dulls the tool very quickly.

G

On Fri, 03 Sep 2004 15:16:36 -0700, Greg
wrote:

Don Foreman wrote:
That's neat! I'll be using that one! Might want a left-hand
endmill so the mill pushes the work down rather than trying to lift
it.

Any endmill will pull if you are cutting with the end face using the
correct direction of rotation. Did you mean using a left-hand endmill
against it's normal rotational direction? You could also do this with a
standard mill using reverse (if your machine has it). Either way it
doesn't cut so well and dulls the tool very quickly.

G
Greg,
I have some end mills with right hand cut, left hand helix flutes.
They look real strange but do prevent the work being pulled into the
cutter. It's best to use them with the end clear so the chips have
somewhere to go. If milling a step and taking much of a cut the chips
are forced back into the cut and a poor finish can result.
ERS

Greg,
I have some end mills with right hand cut, left hand helix flutes.
They look real strange but do prevent the work being pulled into the
cutter. It's best to use them with the end clear so the chips have
somewhere to go. If milling a step and taking much of a cut the chips
are forced back into the cut and a poor finish can result.

No kidding? I learn something new every day. It makes wading through the
cesspit of Usenet worthwhile.

-G

I was thinking of side-milling, with the mill rotating in the intended
direction. A RH spiral cutter would try to lift the work away from
the plate while a LH spiral cutter would push it against the plate.
The pins will resist rotation either way or when using the end face.

On Fri, 03 Sep 2004 15:16:36 -0700, Greg
wrote:


Any endmill will pull if you are cutting with the end face using the
correct direction of rotation. Did you mean using a left-hand endmill
against it's normal rotational direction? You could also do this with a
standard mill using reverse (if your machine has it). Either way it
doesn't cut so well and dulls the tool very quickly.

G

Greg wrote in message ...
Don Foreman wrote:
That's neat! I'll be using that one! Might want a left-hand
endmill so the mill pushes the work down rather than trying to lift
it.

Any endmill will pull if you are cutting with the end face using the
correct direction of rotation. Did you mean using a left-hand endmill
against it's normal rotational direction? You could also do this with a
standard mill using reverse (if your machine has it). Either way it
doesn't cut so well and dulls the tool very quickly.

Nope. I have end mills, RH cut LH helix.

On 1 Sep 2004 22:49:37 -0700, (Dave) calmly
ranted:

I've been pondering the issues of clamping and holding work on a mill
table and I'm really not encouraged. The difficulty in securely
holding the material and yet leaving an empty space around it where
you plan to be cutting it, while still maintaining precise alignment,
seems like a really big headache for any small, thin, or irregularly
shaped (or curved) items. I think I'd need to have a $300 stack of
chopped up parallels and a half-dozen customized sets of vise-jaws to
even begin. Either that or resign myself to adding several unnecessary
threaded holes in each part -- just to hold them down. Am I
exaggerating the difficulty level?

Nope. Dozens of entire books are dedicated to jig building.
Most have much more sophisticated names for it, though.


--

If it weren't for jumping to conclusions, some of us wouldn't get any exercise.
www.diversify.com - Jump-free website programming

Dave wrote:

I've been pondering the issues of clamping and holding work on a mill
table and I'm really not encouraged. The difficulty in securely
holding the material and yet leaving an empty space around it where
you plan to be cutting it, while still maintaining precise alignment,
seems like a really big headache for any small, thin, or irregularly
shaped (or curved) items. I think I'd need to have a $300 stack of
chopped up parallels and a half-dozen customized sets of vise-jaws to
even begin. Either that or resign myself to adding several unnecessary
threaded holes in each part -- just to hold them down. Am I
exaggerating the difficulty level?

Thanks,

Dave


Think extra lugs to clamp or screw down which get milled off in the last
operations.

ffredd

(Dave) wrote in message . com...
Am I
exaggerating the difficulty level?

Probably. A good set of machinists jacks and a good tiedown kit will
handle 99% of what you may run into. Sacrificial blocks beneath the
part that you can cut through without worrying about hurting something
else also come into play. Even cutting up to a clamp, stopping and
moving the clamp to behind the cutter works quite well when the piece
is thin. Clamps made of mild steel or aluminum that you won't be
hurting anything by cutting into them also works. Just don't waste
any more time making them than you have to, doesn't make any sense for
something you're going to use once and toss when you're done.
Reasonable milling vises are cheap, if there's money in a job to cover
it, and you have to cut into it, that works too. Parallels, mine are
all of mild steel, ground, and sometimes drilled and milled into, but
cost is low. Use it once, either toss it or mill and regrind for the
next job.

Not to say that some jobs are not tricky, but the answers usually
don't have to be expensive or complicated.