Extruded aluminum source

ME Newb · Oct 2, 2016

I have a part that takes 6061 tubing with a .002" ID tolerance. One is 1.375" ID and the other is 1.000" ID. Both are .125 wall. Lengths are 8" on small tube and up to 11" on 1.375 tube.

To avoid having to bore the ID I'd like to get some extruded to size but I'm not sure the tolerance can be kept.

Does anyone have a source they've used for custom extrusions? Or somewhere that may stock this since it's a pretty common size?

Right now I'm stuck buying structural tubing from Alro here in Charlotte and boring to size, with I'm assuming, a big carbide boring bar. I think chatter may be a problem.

semfgtech · Oct 2, 2016

Hi,

I guess the tolerance is tooo close for an extrusion..
The tolerance must be atleast 0.01...

Oldwrench · Oct 2, 2016

Extruded 6061 tubing to that accuracy, no way. Drawn seamless 6061 is available in .125 wall and can be made to +/-.002 ID with a special smooth surface. It's known as ACQ ("Air Cylinder Quality"). Problem is you're likely looking at a mill run, which is what we have had to do several times. If you're very lucky some regular drawn material will be small enough on the ID so you can hone it but you have to get lucky.

First I would check with EMJ and see if they can find it in their system, or get you a quote from a US mill. After that (and only after striking out there) try one of the tube sales companies. Good luck.

ME Newb · Oct 3, 2016

Oldwrench said:
Extruded 6061 tubing to that accuracy, no way. Drawn seamless 6061 is available in .125 wall and can be made to +/-.002 ID with a special smooth surface. It's known as ACQ ("Air Cylinder Quality"). Problem is you're likely looking at a mill run, which is what we have had to do several times. If you're very lucky some regular drawn material will be small enough on the ID so you can hone it but you have to get lucky.

First I would check with EMJ and see if they can find it in their system, or get you a quote from a US mill. After that (and only after striking out there) try one of the tube sales companies. Good luck.

Good info. You went through EMJ for the mill run?

Oldwrench · Oct 3, 2016

ME Newb said:
You went through EMJ for the mill run?

Several times. As I recall the minimum was either 1500 lbs or 1500 feet. Once the mill was Alcoa, another time it was a place in Chandler, AZ whose name escapes me (I think it was initials). The last time was about a year ago and a mill made what we needed by redrawing.

EMJ bought the Kilsby-Roberts tube company years ago and that pretty well put them in with all the tubing mills, whereas before they just handled mill runs of steel bar stock. The only downside to mill runs of steel today is that the mills quote less surcharge at time of shipment which is not a quote at all, it's a blank check. I don't know whether that's true right now of aluminum tubing but you would want to read the fine print no matter who quotes it.

Drawn tubing has consistent dimensions and an interior finish like a mirror. You get used to using it and you might never buy extruded again...

robert123 · Oct 3, 2016

Oldwrench said:
Several times. As I recall the minimum was either 1500 lbs or 1500 feet. Once the mill was Alcoa, another time it was a place in Chandler, AZ whose name escapes me (I think it was initials). The last time was about a year ago and a mill made what we needed by redrawing.

Was it Pimalco? That is the company Aloca bought. Much of Alcoa's extrusions come from Chandler, AZ.

Oldwrench · Oct 4, 2016

robert123 said:
Was it Pimalco? That is the company Aloca bought. Much of Alcoa's extrusions come from Chandler, AZ.

That wasn't the name stenciled on the tubing, but it wasn't extruded material in any case.

Ox · Oct 5, 2016

I talked to Alcoa a cpl weeks ago about sourcing material from them, and I was told that they sold off most of their 6000 series mills to SAPA, and were concentrating on 2000 and 7000 series materials.

So when y'all keep saying that you are getting Alcoa commodity stock, I am :confused:

Kaiser never answered neither of my RFQ e-mails either.

---------------------------

I am Ox and I approve this h'yah post!

Milland · Oct 5, 2016

Ox said:
I talked to Alcoa a cpl weeks ago about sourcing material from them, and I was told that they sold off most of their 6000 series mills to SAPA, and were concentrating on 2000 and 7000 series materials.

I am Ox and I approve this h'yah post!

Interesting info, Ox. I'd recently bought some 7075-T651 plate, and wasn't familiar with the mill marking on it. I did a search on it (KUMW), and came up with this older PM post that may interest some: http://www.practicalmachinist.com/vb/cnc-machining/russian-7075-plate-195664/

So be careful out there if you're buying 7xxx Al for critical purposes.

Ox · Oct 5, 2016

I was just told that alum was exempt from DFARS for some reason.
???

-------------

I am Ox, and I approve this h'yah post!

robert123 · Oct 5, 2016

Ox said:
I was just told that alum was exempt from DFARS for some reason.
???

The specialty metals regulations in the DFARS only cover certain metals. They specify domestic or qualifying country sourcing for steel containing minimum percentages of some alloying elements (which covers most stainless and alloy steels), as well as titanium and some less common metals (I think tantalum and zirconium are on the list). There is no requirement for aluminum.

ME Newb · Oct 10, 2016

Gave EMJ a call, told him them I want some pneumatic cylinder tubing. Guy wasn't very helpful but he quoted me some 1-5/8" x .125" drawn tubing and gave me the below guide to tolerances. Unless I'm looking at it wrong then the worst ID tolerance is .0125" and best is .003"? This tubing isn't going to work if that's the case.

Screen Shot 2016-10-10 at 10.54.42 AM.jpg

Screen Shot 2016-10-10 at 10.54.30 AM.jpg

robert123 · Oct 10, 2016

ME Newb said:
Gave EMJ a call, told him them I want some pneumatic cylinder tubing. Guy wasn't very helpful but he quoted me some 1-5/8" x .125" drawn tubing and gave me the below guide to tolerances. Unless I'm looking at it wrong then the worst ID tolerance is .0125" and best is .003"? This tubing isn't going to work if that's the case.

View attachment 182098

View attachment 182099

Those are tables out of ANSI H35.2. They are standard tolerances for drawn tube. For 6061-T6 at 1" OD x .125" wall, it is allowed +/- .008" on the OD and +/- 10% or +/- .0125" on the wall thickness. Taking these together, the ID could be between .717" and .783" (or .750" +/- .033"). For 1.375" OD, the OD tolerance is +/- .010" which would allow an ID variation of +/- .035".

That being said, the drawn tube I have received is usually fairly close to nominal but I would not expect +/- .002".

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