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View Full Version : Ideas for making a ~20" dia flat ring of flat aluminum?



gellfex
10-29-2009, 05:48 PM
I've got a problem job where one possible solution involves making 3 large "bearings" of roughly 20" diameter flat rings (like a washer) of say, 1/8x1 flat 6061. I'll be making some V-groove bearing trucks to hold it and let it spin. (no, a commercial lazy susan bearing won't work. I need the center clear and the whole rig light)

Routing them out of a sheet is doable but incredibly wasteful at $70 for a 2'x2'. I don't have a flat rolling mill, just a slip roll. But buying or building a flat rolling rig will make that $210 seem like a bargain, and I'd still have to weld and finish out the joint.

Any other ways of going at this I'm missing? Or know of where they've got something like this lying around?

Limy Sami
10-29-2009, 05:56 PM
I've got a problem job where one possible solution involves making 3 large "bearings" of roughly 20" diameter flat rings (like a washer) of say, 1/8x1 flat 6061. I'll be making some V-groove bearing trucks to hold it and let it spin. (no, a commercial lazy susan bearing won't work. I need the center clear and the whole rig light)

Routing them out of a sheet is doable but incredibly wasteful at $70 for a 2'x2'. I don't have a flat rolling mill, just a slip roll. But buying or building a flat rolling rig will make that $210 seem like a bargain, and I'd still have to weld and finish out the joint.

Any other ways of going at this I'm missing? Or know of where they've got something like this lying around?

If they have to be flat then I'd definitely go the cut from plate route, rolling & welding a ring is almost easy,............... when compared with getting the !"$%^&"$%^&* thing flat.

boslab
10-29-2009, 06:09 PM
roll from angle, then cut away the leg
mark

Evan
10-29-2009, 06:32 PM
Angle won't roll flat. Too much stretching or compressing of the planar flange for it to stay flat. The only practical way that comes to mind is to weld up chordal sections. They can be cut nested from a piece with little waste.

knedvecki
10-29-2009, 06:38 PM
Are you any good wiih casting, as in foundry work?

Black_Moons
10-29-2009, 07:15 PM
How about taking a commerical lazy suzan and choping/grinding/cutting the center and everything else out? (assumeing you don't need it to stay togethor on its own)

John Stevenson
10-29-2009, 07:20 PM
Get it laser cut.
Welding will distort and cause problems as will rolling.

If you want it flat, start with flat.

.

Black_Moons
10-29-2009, 07:22 PM
I wonder what the wall thickness 20" steel pipe comes in.
Of course, getting a straight cutoff would be quite the challange.. likey needing a few passes on a surface grinder or somesuch.

Alternatly what you do is buy the 2x2' bits of plate, very carefuly cut the biggest ID hole you can and save the nice round chunk of plate for the next time you need 19" lazy susans... or err, something else. :) you know a 19" round will be usable for something along the way, even if its only 1/2 usable due to the weird shape.. but maybe you'll find you NEED it round and use 90%+ of it.

Evan
10-29-2009, 07:40 PM
Perhaps a 20" aluminum bicycle rim would be of some use? Many have walls that range from 1/2 to 3/4" wide and are perpendicular to the axle. You can probably pick some up for nothing or close to it at a local bicycle repair shop or a yard sale.

http://ixian.ca/pics6/bikerim.jpg

gda
10-29-2009, 07:44 PM
Another vote for starting with flat plate and keeping it flat.

If you need it REALLY flat you can use Jig Plate. I priced some out this week: $931 for a 1/4" THK 4' X 8' sheet!

A lower cost option: I think STOP signs are about 1/8" thick and made of aluminum.

Evan
10-29-2009, 08:04 PM
A lower cost option: I think STOP signs are about 1/8" thick and made of aluminum.


Yeah, but they are fastened with those pesky anti tamper screws... :D

Black_Moons
10-29-2009, 08:51 PM
Left handed drill bit says anti-wut?

winchman
10-30-2009, 12:16 AM
What exactly is a "V-groove bearing truck"?

What does the structure look like below and above the bearing?

Why not something like these? http://store.workshopsupply.com/catalogue/product_info.php?products_id=2604

This one's actually the right size: http://www.instawares.com/aluminum-lazy-susan-platform-jr9660.jr9660.0.7.htm

http://img.photobucket.com/albums/1003/winchman/lazysusanbearing.jpg

You get three for $75 with free shipping.

Roger

lenord
10-30-2009, 12:41 AM
Google up Inca Corp. and get an call/e-mail to George Roberts.

24,17 and 10" bearings

You can get 1" thik Mic6 drops up to 18.750 or 18.625" (?) OD from sandsmachine.com too. They have other round drops too. They make a large OD bearing.

Lenord

Circlip
10-30-2009, 08:00 AM
Sorry to differ Sir John, for flat Alumin rings go for waterjet cut, NO heat stress at all.

Regards Ian.

Rich Carlstedt
10-30-2009, 12:57 PM
I think you are way over pricing your raw material
70 bucks for 1/8 thick 2 x 2 6061 sheet is outrageous.

Go here
http://www.onlinemetals.com/merchant.cfm?pid=1246&step=4&showunits=inches&id=76&top_cat=60

For one piece, its little more than half your price ( 43).


If you are paranoid over cost, ( as I am sometimes, depending on use)
just go to your local junk/recycle yard.
I have bought Aluminum plate in great shape ( New sometimes) for a little (2x) over scrap price as they deserve a profit

I bought a 3/4 6061 plate two years ago for 1/4 price new

gellfex
10-30-2009, 03:15 PM
Thanks for all the great ideas!!!

Yeah, laser or water cutting flat sheet seems the way to go. Winchman, those ring bearings are relatively heavy, between 4.5 and 7.5 lb depending on dia. This is for a theatrical novelty costume skirt like a tutu, even 4lb is a bit much. The rings held together with 4 "V-groove" bearings would be pretty light. A V-groove bearing has a groove around the outside so you can trap a track between a pair of them.

http://www.pacific-bearing.com/assets/0/24/188/192/242/298/c71db5f9-7861-45b7-a04b-409c86f68033.jpg

winchman
10-30-2009, 05:08 PM
At only two pounds each, it seems like the lazy susan bearing would be lighter than the V-groove bearings and the structure needed to support them rigidly enough to work well.

Product Specifications

Product Name: Aluminum Lazy Susan Platform - 20
Manufacturer Name: Johnson-Rose Corp.
Product ID: JR9660
Dimension (L x W x H): 20 x N/A xN/A
Shipping Weight: 5 lbs.
Product Weight: 2 lbs.


Roger

gellfex
10-30-2009, 05:32 PM
At only two pounds each, it seems like the lazy susan bearing would be lighter than the V-groove bearings and the structure needed to support them rigidly enough to work well.

Product Specifications

Product Name: Aluminum Lazy Susan Platform - 20
Manufacturer Name: Johnson-Rose Corp.
Product ID: JR9660
Dimension (L x W x H): 20 x N/A xN/A
Shipping Weight: 5 lbs.
Product Weight: 2 lbs.


Roger

Those V bearings can be small as 3/4", so added to 2 1/8 rings it'd be roughly 2lbs. you could be right anyway since buying off the shelf is MUCH easier!

The weight for the similar item from McMaster was 4.5 lb. Could they have quoted the shipping weight?

jkilroy
10-30-2009, 05:35 PM
Cutting them from flat plate sounds like the fast and easy, therefore cheap in the long run, solution.