Hello,
I'm getting ready to turn some small parts out of aluminum.
The parts I'm making are basically discs of about 24mm diameter and 3mm
thickness with a few holes drilled for lightening. The most important
criteria are beauty (looks good with no gauling) and machinability.

I've seen all sorts of grades and am confused as to which is the better
grade to use.
What grade aluminum should I get and what type of tool. HSS or Carbide?

Any other tips I could use?

Thanks

James

"James Holbrook" wrote in message
news:XrYLd.7157$HZ.2520@okepread07...
Hello,
I'm getting ready to turn some small parts out of aluminum.
The parts I'm making are basically discs of about 24mm diameter and 3mm
thickness with a few holes drilled for lightening. The most important
criteria are beauty (looks good with no gauling) and machinability.

I've seen all sorts of grades and am confused as to which is the better
grade to use.
What grade aluminum should I get and what type of tool. HSS or Carbide?

Any other tips I could use?

Thanks

James

You didn't mention if you're interested in starting with round stock or
sheet material-----and they can be made from either one easily. It might be
more helpful in getting an opinion in keeping with your project. Shooting
from the hip, though, I offer this:

For beauty in machining, there's nothing quite like 7075-T6. It cuts with a
bright, smooth finish, assuming you have sharp tools and apply them
properly. Next choice would be 2024-T351 or T4, but it doesn't cut with
the nice, bright shiny surface you get from 7075. My last choice would
be 6061-T6, but it would be a better choice than 2024 if you expect a shiny
surface. 2024 tends to cut with a somewhat dull surface, somewhat
resembling cast iron, but without the graphite. In all cases, use kerosene
or some WD-40 to lubricate your cuts. You can apply it with an acid brush,
or a small paint brush.

If you're adept at hand grinding turning tools, there's absolutely nothing
wrong with using HSS with some serious positive rake. If not, and you're
uncomfortable sharpening toolbits, I'd suggest a positive rake carbide with
a chip breaker. Choose a corner radius that is in keeping with the surface
finish you desire and doesn't cause chatter, say 1/32". You don't need
carbide for aluminum and I'd encourage you to learn to grind toolbits if you
don't already. Nothing will set you free when running a lathe more than
that will.

Harold

James Holbrook wrote in news:XrYLd.7157$HZ.2520
@okepread07:

Hello,
I'm getting ready to turn some small parts out of aluminum.
The parts I'm making are basically discs of about 24mm diameter and 3mm
thickness with a few holes drilled for lightening. The most important
criteria are beauty (looks good with no gauling) and machinability.

I've seen all sorts of grades and am confused as to which is the better
grade to use.
What grade aluminum should I get and what type of tool. HSS or Carbide?

Any other tips I could use?

Thanks

James

If you want the best possible finish, a diamond tool is it for aluminum
(PCD tipped tool). Get the largest radius your part geometry will allow.
6061 or 7075 for the material.



--
Anthony

You can't 'idiot proof' anything....every time you try, they just make
better idiots.

Remove sp to reply via email

You can get 6061 to a mirror fish with the dish soap and polishing with a
fine wool. I use a good mixture of water and dish soap, rub or turn with
steel wool and it will shine very nice.
"Anthony" wrote in message
...
James Holbrook wrote in news:XrYLd.7157$HZ.2520
@okepread07:

Hello,
I'm getting ready to turn some small parts out of aluminum.
The parts I'm making are basically discs of about 24mm diameter and 3mm
thickness with a few holes drilled for lightening. The most important
criteria are beauty (looks good with no gauling) and machinability.

I've seen all sorts of grades and am confused as to which is the better
grade to use.
What grade aluminum should I get and what type of tool. HSS or Carbide?

Any other tips I could use?

Thanks

James

If you want the best possible finish, a diamond tool is it for aluminum
(PCD tipped tool). Get the largest radius your part geometry will allow.
6061 or 7075 for the material.



--
Anthony

You can't 'idiot proof' anything....every time you try, they just make
better idiots.

Remove sp to reply via email

In article ,
Anthony wrote:
James Holbrook wrote in news:XrYLd.7157$HZ.2520
@okepread07:

Hello,
I'm getting ready to turn some small parts out of aluminum.
The parts I'm making are basically discs of about 24mm diameter and 3mm
thickness with a few holes drilled for lightening. The most important
criteria are beauty (looks good with no gauling) and machinability.

I've seen all sorts of grades and am confused as to which is the better
grade to use.
What grade aluminum should I get and what type of tool. HSS or Carbide?

[ ... ]

If you want the best possible finish, a diamond tool is it for aluminum
(PCD tipped tool). Get the largest radius your part geometry will allow.
6061 or 7075 for the material.

Agreed -- though PCD diamond can be rather expensive. And
*never* use them on steel or iron. They are hard enough, but hot steel
or iron tends to dissolve carbon (including diamonds) into the alloy,
making it harder.

Don't confuse PCD (PolyCrystalaine Diamond) with the so-called
"diamond tool holder", which holds a HSS lathe bit at an angle which
presents a diamond-shape cutting surface.

And if you use carbide inserts (one of the suggestions in
Harold's branch of the thread -- if you are not up to grinding your own
HSS toolbits), *don't* use TiN (Titanium Nitride -- a yellow-gold color)
coated carbide. TiN coatings rounds the edges slightly, making for
duller tools. Aluminum wants the sharpest edge that you can get. The
best of the carbide inserts are the ones which have been ground to final
dimensions, instead of just formed as sintered to final shape which is
common. (I've got some very small ones, in 55 degree diamond shape
which fit the tool holders for my Emco Maier Compact-5/CNC which I
sometimes use when I need a really sharp carbide on my larger machines,
as they are ground to final dimensions.

TiN coatings are good for other materials, such as steel, where
they avoid BUE (Built-Up Edge -- an accumulation of metal which welds
itself to the edge and destroys the resulting finish.)

Good Luck,
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 ---

Anthony wrote in
:

James Holbrook wrote in
news:XrYLd.7157$HZ.2520 @okepread07:

Hello,
I'm getting ready to turn some small parts out of aluminum.
The parts I'm making are basically discs of about 24mm diameter and
3mm thickness with a few holes drilled for lightening. The most
important criteria are beauty (looks good with no gauling) and
machinability.

I've seen all sorts of grades and am confused as to which is the
better grade to use.
What grade aluminum should I get and what type of tool. HSS or
Carbide?

Any other tips I could use?

Thanks

James

If you want the best possible finish, a diamond tool is it for
aluminum (PCD tipped tool). Get the largest radius your part geometry
will allow. 6061 or 7075 for the material.

I'm gonna quibble with this a little. Although I'm sure Anthony already
knows this, someone else might find it interesting. A PCD tipped tool
won't give you the best possible finish in Aluminum. PCD or
Poly-crystaline diamond is made up of many diamond crystals. A single
crystal diamond, usually a natural low grade gemstone, will give the
best possible finish, since the cutting edge can be lapped to a flawless
condition. With a PCD tool there is some "un-eveness" due to the
multiple crystals. I have a polygonal mirror on my desk that was face
milled in Aluminum with a natural diamond tool. Also, video tape
recorders have drum heads that are turned with a single crystal tool.
Look inside a VCR. The head is aluminum and that is a turned finish.
Pretty amazing. Thing is, you need a damn good spindle and a very good
servo system.

Dan

Dan Murphy wrote in
:

Anthony wrote in
:


I'm gonna quibble with this a little. Although I'm sure Anthony
already knows this, someone else might find it interesting. A PCD
tipped tool won't give you the best possible finish in Aluminum. PCD
or Poly-crystaline diamond is made up of many diamond crystals. A
single crystal diamond, usually a natural low grade gemstone, will
give the best possible finish, since the cutting edge can be lapped to
a flawless condition. With a PCD tool there is some "un-eveness" due
to the multiple crystals. I have a polygonal mirror on my desk that
was face milled in Aluminum with a natural diamond tool. Also, video
tape recorders have drum heads that are turned with a single crystal
tool. Look inside a VCR. The head is aluminum and that is a turned
finish. Pretty amazing. Thing is, you need a damn good spindle and a
very good servo system.

Dan



Agreed Dan, however, within the budget of just about anyone, PCD would
be the next choice. Monocrystal diamond tools in any useful size are
*extremely* expensive. We do use some, but only in applications where
the specific advantages they offer are absolutely required.

PCD grain size (PCD Grade) will determine, to a large degree, the
surface finish you get. Using a fine grade (say GE 1500), will provide a
better finish, but really should only be used for light finishing cuts,
as you have much smaller diamond crystals which are easier to rip out of
the binder along the edge. However, you do get a much smoother edge on
the tool, with smaller binder gaps between crystals, hence better
surface finish. You want to use a very coarse grained PCD tool for
roughing operations. The crystals are larger, but the binder has a
better grasp on the crystals, so they aren't as easy to rip out. You
will have a rougher surface due to the larger gaps of binder between
crystals, however.

Unless you are doing mirrors, or some automotive/electronics/NASA type
stuff, the differences are unnoticable to the average machinist. You can
really only see the differences when doing microscopic inspections of
the surface.





--
Anthony

You can't 'idiot proof' anything....every time you try, they just make
better idiots.

Remove sp to reply via email

I've ordered some 2024 and 7071 stock. I have some 6061 already. Will
try all three.
I'm using a Taig lathe and the parts are small. 24mm in diameter and 6mm
thick with a few holes drilled for lightening.
I'm looking to buy some tools. Will these work OK? I have yet to find a
source for PCD tools on the internet.

http://www.grizzly.com/products/item...emnumber=G5639

Any place else to get something that will be better if these aren't up
to the job?

Thanks!
James


Anthony wrote:
James Holbrook wrote in news:XrYLd.7157$HZ.2520
@okepread07:


Hello,
I'm getting ready to turn some small parts out of aluminum.
The parts I'm making are basically discs of about 24mm diameter and 3mm
thickness with a few holes drilled for lightening. The most important
criteria are beauty (looks good with no gauling) and machinability.

I've seen all sorts of grades and am confused as to which is the better
grade to use.
What grade aluminum should I get and what type of tool. HSS or Carbide?

Any other tips I could use?

Thanks

James


If you want the best possible finish, a diamond tool is it for aluminum
(PCD tipped tool). Get the largest radius your part geometry will allow.
6061 or 7075 for the material.

Anthony wrote in
:

snip

Agreed Dan, however, within the budget of just about anyone, PCD would
be the next choice. Monocrystal diamond tools in any useful size are
*extremely* expensive. We do use some, but only in applications where
the specific advantages they offer are absolutely required.

PCD grain size (PCD Grade) will determine, to a large degree, the
surface finish you get. Using a fine grade (say GE 1500), will provide
a better finish, but really should only be used for light finishing
cuts, as you have much smaller diamond crystals which are easier to
rip out of the binder along the edge. However, you do get a much
smoother edge on the tool, with smaller binder gaps between crystals,
hence better surface finish. You want to use a very coarse grained PCD
tool for roughing operations. The crystals are larger, but the binder
has a better grasp on the crystals, so they aren't as easy to rip out.
You will have a rougher surface due to the larger gaps of binder
between crystals, however.

Unless you are doing mirrors, or some automotive/electronics/NASA type
stuff, the differences are unnoticable to the average machinist. You
can really only see the differences when doing microscopic inspections
of the surface.

Anthony,
I got a quick question for you. I read an article in IDR (Industial
Diamond Review)a couple of years ago, where DeBeers did some test
cutting in Titanium using PCD tooling. The economics looked pretty good.
Have you had a chance to try them in Titanium? My Kennametal rep was
going to get an insert for me, it was the same tool used in the study,
but it wasn't available yet. I'd forgotten about it until now. I'd like
to hear from anyone cutting Ti with diamond tools.

Dan

I am too impatient to wait for some tool bits to arrive. For aluminum
I would use a steel tool bit and grind in more relief than you would
use for steel.
If you don't need lots of these parts, you can always finish them to a
high polish using sandpaper in various grades. Walmart has sandpaper
finer than 600 grit.

Dan

Dan Murphy wrote in
:



Anthony,
I got a quick question for you. I read an article in IDR (Industial
Diamond Review)a couple of years ago, where DeBeers did some test
cutting in Titanium using PCD tooling. The economics looked pretty
good. Have you had a chance to try them in Titanium? My Kennametal rep
was going to get an insert for me, it was the same tool used in the
study, but it wasn't available yet. I'd forgotten about it until now.
I'd like to hear from anyone cutting Ti with diamond tools.

Dan


Not cut any Ti with them....I'm wondering though, DeBeers brought out a
90 micron crystal size diamond for a while, a couple of years ago,
mostly for testing. The results of our tests looked very good, but they
claimed the demand wasn't there for them to produce it. I wonder if this
is the same thing you are talking about.



--
Anthony

You can't 'idiot proof' anything....every time you try, they just make
better idiots.

Remove sp to reply via email

"Jack P. Flash" wrote in news:NBrMd.4$ds.1@okepread07:

I've ordered some 2024 and 7071 stock. I have some 6061 already. Will
try all three.
I'm using a Taig lathe and the parts are small. 24mm in diameter and
6mm thick with a few holes drilled for lightening.
I'm looking to buy some tools. Will these work OK? I have yet to find
a source for PCD tools on the internet.

http://www.grizzly.com/products/item...emnumber=G5639

Any place else to get something that will be better if these aren't up
to the job?

Thanks!
James

Try Kennametal, Iscar, Vertex, Citco Diamond, and a host of others. They
may not be shown in the regular catalogs, but about any style insert they
have can be ordered PCD tipped.




--
Anthony

You can't 'idiot proof' anything....every time you try, they just make
better idiots.

Remove sp to reply via email

Anthony wrote in
:

Dan Murphy wrote in
:



Anthony,
I got a quick question for you. I read an article in IDR (Industial
Diamond Review)a couple of years ago, where DeBeers did some test
cutting in Titanium using PCD tooling. The economics looked pretty
good. Have you had a chance to try them in Titanium? My Kennametal
rep was going to get an insert for me, it was the same tool used in
the study, but it wasn't available yet. I'd forgotten about it until
now. I'd like to hear from anyone cutting Ti with diamond tools.

Dan


Not cut any Ti with them....I'm wondering though, DeBeers brought out
a 90 micron crystal size diamond for a while, a couple of years ago,
mostly for testing. The results of our tests looked very good, but
they claimed the demand wasn't there for them to produce it. I wonder
if this is the same thing you are talking about.

I'll bet that was the tool. I showed the article to our Kennametal rep.
to see what he thought of it. We have a really good rep., most tooling
companies put their best guys servicing OEM accounts. Anyway he ws
familiar with the tool as they were doing some testing with it and
considering it for a new grade, IIRC. He was never able to get one for
us to play around with. It seems every time I find something new for
titanium it never pans out.

Dan

Dan Murphy wrote in
:



I'll bet that was the tool. I showed the article to our Kennametal rep.
to see what he thought of it. We have a really good rep., most tooling
companies put their best guys servicing OEM accounts. Anyway he ws
familiar with the tool as they were doing some testing with it and
considering it for a new grade, IIRC. He was never able to get one for
us to play around with. It seems every time I find something new for
titanium it never pans out.

Dan



Dan,
Get in touch with your local Sumitomo rep. They have a large crystal pcd
chip. Not the same as DeBeers, and more costly (Sumitomo is more
expensive in general, but they do have better quality on some products).
This might work for Ti, you'll have to discuss that with the rep. What
kills us on Sumitomo is lead time. Most of the tools are made in Japan,
so lead time can be an issue, if it isn't a stock item. The majority of
what we use is custom made.



--
Anthony

You can't 'idiot proof' anything....every time you try, they just make
better idiots.

Remove sp to reply via email