Author Topic: Cast Aluminum Precision Tool & Jig Plate (source)  (Read 3684 times)

Offline tvoght

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Cast Aluminum Precision Tool & Jig Plate (source)
« on: March 30, 2015, 07:04:31 PM »
I very often use cast aluminum tooling plate in my setups. It is already machined (to a 25 RMS finish, whatever that means) and with a good thickness tolerance. It's very stable when machined, so it can be clamped to the mill table and used sacrificially, or used to make fixtures. I also make engine parts from it.

I use it because I had stumbled across a surplus source of it. A company uses it in a a manufacturing process, and has tons (literally) of stock disks of it on hand.
All the stock is round disks which have a few small holes drilled near the periphery. The prices per square inch is considerably lower (say 70% lower) than you would pay for the material elsewhere. I think it is ideal for hobby machining. Those in the U.S. may want to check it out here:

http://www.sandsmachine.com/alumweb.htm

I'm not affiliated in any way, just a satisfied customer.

--Tim

Offline b.lindsey

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Re: Cast Aluminum Precision Tool & Jig Plate (source)
« Reply #1 on: March 30, 2015, 08:30:17 PM »
Wow Tim, given the quantity discounts they show, they literally must have tons of them on hand. Do you know what they use them for ?

Bill

Offline tvoght

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Re: Cast Aluminum Precision Tool & Jig Plate (source)
« Reply #2 on: March 30, 2015, 09:56:50 PM »
Bill,
The website explains some of it. They manufacture an unusual - and quite large - ball bearing of some kind. I believe the bearing frame is made of this cast plate and the balls are plastic. I think the disks they sell are whats left after the middle is cut out of the bearing frame. The web site is kind of interesting to read through.

The site says they have 100 tons of surplus plate on hand, and stacking more each day.

--Tim

Offline mklotz

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Re: Cast Aluminum Precision Tool & Jig Plate (source)
« Reply #3 on: March 30, 2015, 10:15:46 PM »
Looks like they would make excellent sacrificial tops for rotary tables.  Not to mention increasing table size for many of the smaller size RTs.
Regards, Marv
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Offline b.lindsey

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Re: Cast Aluminum Precision Tool & Jig Plate (source)
« Reply #4 on: March 31, 2015, 12:15:34 AM »
Thanks Tim. I guess I didn't get past the sheer numbers on first look. I have corrected that :)  Thanks for sharing this unique source.

Bill

Offline petertha

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Re: Cast Aluminum Precision Tool & Jig Plate (source)
« Reply #5 on: March 31, 2015, 03:13:58 AM »
I'm definitely interested in this stuff & also for my RT. Thanks for posting. Not so much the sacrificial part (although for the price...). I've always wanted to make tooling plates with a matrix pattern of threaded holes so I can better accommodate odd-ball parts setups rather than fussing with strap clamps across the T-slots inevitably seem to be in the wrong position. I cant find cast iron slabs locally/cheaply & suspect even HRS might distort a bit, although it would be desirably harder.

Once upon a time I looked at pre-threaded tooling plates like this. But at a cost of $550 for 12x12x0.5" it was a very short look. They don't say what brand but do mention cast aluminum plate (and they anodized).
http://www.raycofixture.com/fixture-plates/aluminum-casted-fixture-plates/m20-threaded-fixture-plates/

I wanted to draw attention to the dimensional specs & maybe someone can clarify...

"Each side is machined to a maximum 20 microinch or 0.50 micron smoothness".

"The tolerance for any thickness is ±.005” /±.127mm. Maximum deviation from flat: Specified plate thickness maximum variation:
3/4” and over: .005” / 19mm and over: .127mm 1/4” to 5/8”: .015” / 6mm and over: .381mm


So it appears to be very smooth as a standalone surface (0.00002"). I don't think I really care about thickness tolerance. But how do I interpret the 'deviation from flat' specs? What is typical for metal plates, say a lapping plate as a high end example?

ps - notice what typical metal suppliers charges for a comparable chunk vs. this inventory reduction price
http://www.speedymetals.com/showproduct.aspx?productid=2928


 

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