Octagonal aluminum bar stock?

Octagonal aluminum bar stock?

Post by Jon Anderso » Wed, 10 Sep 2008 07:26:23



Anyone know of a source for aluminum bar in an octagonal
cross section? 5/16 or 9mm across flats, prefer 6061 to
insure anodize color match with a related part. I'm guessing
this is not available, haven't found anything via Google,
but thought I'd ask anyway.

Jon

 
 
 

Octagonal aluminum bar stock?

Post by spamTHIS.. » Wed, 10 Sep 2008 06:44:08



Quote:
> Anyone know of a source for aluminum bar in an octagonal
> cross section? 5/16 or 9mm across flats, prefer 6061 to
> insure anodize color match with a related part. I'm guessing
> this is not available, haven't found anything via Google,
> but thought I'd ask anyway.

> Jon

Hex is easy- but octagonal?

Could take square and knock the corners off, but that's a fair bit of
removal.

Dave

 
 
 

Octagonal aluminum bar stock?

Post by Jon Anderso » Wed, 10 Sep 2008 08:07:21


Quote:

> Hex is easy- but octagonal?

> Could take square and knock the corners off, but that's a fair bit of
> removal.

It's for an ultra high tech carbon fiber violin bow,
octagonal profile matches the bow so hex won't cut it.
Options are octagon, knurl, or some sort of shallow fluting.
But not worth the time/expense of profiling the OD to get
the octagon.

(dang, wish my Omniturn had the indexing spindle!)

Jon

 
 
 

Octagonal aluminum bar stock?

Post by TwoGun » Wed, 10 Sep 2008 08:17:21



Quote:
> Anyone know of a source for aluminum bar in an octagonal
> cross section? 5/16 or 9mm across flats, prefer 6061 to
> insure anodize color match with a related part. I'm guessing
> this is not available, haven't found anything via Google,
> but thought I'd ask anyway.

> Jon

If you go to VarmintAls.com , I hope that URL is correct, click on his
Mini-Lathe page and scroll down to a direct link to Online Metals. I
was just browsing their site today and I am pretty sure I saw some Hex
or octagonal bar stock but I am not sure of the alloy number.

Dennis

 
 
 

Octagonal aluminum bar stock?

Post by F. George McDuffe » Wed, 10 Sep 2008 08:34:07


On Mon, 08 Sep 2008 15:07:21 -0800, Jon Anderson

Quote:


>> Hex is easy- but octagonal?

>> Could take square and knock the corners off, but that's a fair bit of
>> removal.

>It's for an ultra high tech carbon fiber violin bow,
>octagonal profile matches the bow so hex won't cut it.
>Options are octagon, knurl, or some sort of shallow fluting.
>But not worth the time/expense of profiling the OD to get
>the octagon.

>(dang, wish my Omniturn had the indexing spindle!)

>Jon

========
You may want to contact the custom aluminum extrusion houses.
They may have a stock die for what you want, or for this simple a
profile it should be cheap to edm one.  Be sure to check material
and physical properties/temper.  A few places you can try
http://www.paramountextrusions.com/shapes.htm
http://www.zycon.com/Products/Aluminum-Extrusions.html?src=google&gcl...

web page showing octagons
http://www.argylein.com/extrudes.html
http://www.argylein.com/search_dies-n.php?words=OCT

google on <octagon "aluminum extrusions"> for c. 700 hits.
register on
http://www.globalspec.com/MyGlobalSpec/NewProfileConfirm?RegUserID=-1...
for a bunch more.

 
 
 

Octagonal aluminum bar stock?

Post by Jon Anderso » Thu, 11 Sep 2008 01:18:57


Quote:

> I am pretty sure I saw some Hex or octagonal bar stock but I am not sure of the alloy number.

Thanks, I tried all the online sources I could think of,
nobody has it. Funny though, lots of places list weight per
foot for octagon materials, nobody supplies it....

Jon

 
 
 

Octagonal aluminum bar stock?

Post by Jon Anderso » Thu, 11 Sep 2008 01:33:55


Quote:

> You may want to contact the custom aluminum extrusion houses.

Only problem with extruders is the minimums. A single 20'
length would be a several year supply. And there are two
other sizes I need to make. A 1000lb order which is a common
min. order would last for several centuries! Customer is not
unwilling to invest, but probably not for inventory that
will outlast him and his kids.... <G>

Think I've figured out an approach though, will just chamfer
mill short lengths of material in the mill, then turn. Not
the most efficient approach, but it's a low volume high
value part that would certainly justify it.

Jon

 
 
 

Octagonal aluminum bar stock?

Post by Jim Wilkin » Thu, 11 Sep 2008 00:59:45



Quote:

> Think I've figured out an approach though, will just chamfer
> mill short lengths of material in the mill, then turn. Not
> the most efficient approach, but it's a low volume high
> value part that would certainly justify it.

> Jon

For short lengths a 5C spin index should work well.
 
 
 

Octagonal aluminum bar stock?

Post by Jon Anderso » Thu, 11 Sep 2008 02:54:19


Quote:

> For short lengths a 5C spin index should work well.

The entire length of the finished part is octagonal. Yes, I
could make it out of round stock in this manner, but then
would have to move to the lathe to part off, or hack saw
off. While quantities are low by production standards, I
could be making up to 100 pcs in each of three different
sizes, and that would be a big pain. Also, we're looking at
multiple grooves, or finning, just as a way to reduce
weight. If the part was already to length it would require
handling twice, turning the part around in the collet.
If I had an 8" length, I could proceed to make the part
complete in one smooth process. I'd just be changing 'bars'
a lot more often that I'd originally wanted to.

For perspective, this is for a high tech violin bow made
from carbon fiber. Customer is going to the expense of
buying 5-40 threaded titanium screws from Germany and having
me make as light an aluminum knob for the end as we can, all
to shave another gram or so. It's a production process, the
focus is on end results, not cost. Yet, we don't have
anywhere near the volume to justify custom extrusions.

Appreciate the input though!

Jon

 
 
 

Octagonal aluminum bar stock?

Post by _ » Thu, 11 Sep 2008 01:59:31


Quote:


>> For short lengths a 5C spin index should work well.

> The entire length of the finished part is octagonal. Yes, I
> could make it out of round stock in this manner, but then
> would have to move to the lathe to part off, or hack saw
> off. While quantities are low by production standards, I
> could be making up to 100 pcs in each of three different
> sizes, and that would be a big pain. Also, we're looking at
> multiple grooves, or finning, just as a way to reduce
> weight. If the part was already to length it would require
> handling twice, turning the part around in the collet.
> If I had an 8" length, I could proceed to make the part
> complete in one smooth process. I'd just be changing 'bars'
> a lot more often that I'd originally wanted to.

> For perspective, this is for a high tech violin bow made
> from carbon fiber. Customer is going to the expense of
> buying 5-40 threaded titanium screws from Germany and having
> me make as light an aluminum knob for the end as we can, all
> to shave another gram or so. It's a production process, the
> focus is on end results, not cost. Yet, we don't have
> anywhere near the volume to justify custom extrusions.

> Appreciate the input though!

> Jon

Anneal and press the round stock through a hex hole in hardened steel.  
 
 
 

Octagonal aluminum bar stock?

Post by BJ » Thu, 11 Sep 2008 10:39:52


Try this site

http://www.speedymetals.com/default.aspx

--
Bruce

"You know that old Beach Boys song, Bomb Iran? Bomb bomb bomb, bomb bomb
Iran."
John McSame , More Bush in more places!!!

 
 
 

Octagonal aluminum bar stock?

Post by glyf.. » Thu, 11 Sep 2008 21:07:02


Quote:
> > For short lengths a 5C spin index should work well.

> The entire length of the finished part is octagonal. Yes, I
> could make it out of round stock in this manner, but...

I was thinking he meant with a square collet.  Actually, with a square
collet, you may not even need a spin index, just a square collet
block, and mount the collet in the block at 45 degrees...
  --Glenn Lyford
 
 
 

Octagonal aluminum bar stock?

Post by Jon Anderso » Thu, 11 Sep 2008 23:37:09


Quote:

> I was thinking he meant with a square collet.  Actually, with a square
> collet, you may not even need a spin index, just a square collet
> block, and mount the collet in the block at 45 degrees...

That would require indexing the collet to get the stock at
the 45 degrees. Starting with round stock means more passes
but much lighter cuts. It still leaves me with either a part
I have to handle twice in the lathe to do the grooving, or
waste a significant bit of material leaving extra in the
collet. Though low production, it's still a production
process and flipping a collet block 400 times gets tedious.

Jon

 
 
 

Octagonal aluminum bar stock?

Post by _ » Fri, 12 Sep 2008 00:33:10


Quote:


>> I was thinking he meant with a square collet.  Actually, with a square
>> collet, you may not even need a spin index, just a square collet
>> block, and mount the collet in the block at 45 degrees...

> That would require indexing the collet to get the stock at
> the 45 degrees. Starting with round stock means more passes
> but much lighter cuts. It still leaves me with either a part
> I have to handle twice in the lathe to do the grooving, or
> waste a significant bit of material leaving extra in the
> collet. Though low production, it's still a production
> process and flipping a collet block 400 times gets tedious.

> Jon

Hey - if it's fairly soft aluminium and you have a good-sized lathe, press
an octagonal die over the stock with the tailstock.  Drill, thread, press,
cut, all with one instance of work-holding.

How much is he going to sell these bows for?  My sister told me how much
her hi-end bow was once and it made my eyes open *quite* wide.

 
 
 

Octagonal aluminum bar stock?

Post by Jim Wilkin » Fri, 12 Sep 2008 01:05:07



Quote:
> > > For short lengths a 5C spin index should work well.

> I was thinking he meant with a square collet. ?Actually, with a square
> collet, you may not even need a spin index, just a square collet
> block, and mount the collet in the block at 45 degrees...
> ? --Glenn Lyford

You can only rotate the collet if you move the guide pin.

I chuck round stock in a 3 jaw chuck with a 5C mount and move it back
and forth between the lathe and mill as needed.