Greetings All,

I've seen the images of the very nicely done three wheeled rolling
tubing bender in the drop box. I'd like to use something similar to
roll some 1" wide 1/4" thick Al flat stock the "Hard way" (aka
on-edge)

What I need to fabricate is a 1/4" thick ring of Aluminum that is 18"
ID and 20" OD. I need to make several of these, and cutting them from
sheet stock gets expensive quickly.

So I'm thinking all I need to do is change the rollers in the afore
mentioned tubing bender. The question is, what dimensions to make the
new rollers.

A) How deep will the square groove in the rollers need to be? Do I
need a full 1" radial recesses in the rollers to properly keep the
flat stock from wanting to twist during the bending process?

B) How wide should the grooves in the rollers be? Should all three
rollers have the same groove dimensions? I ask as the flat stock is
0.25" nominal thickness. I'm assuming that as I roll the flat stock,
the outside edge of the ring is probably going to stretch to a thinner
dimension, while the inside edge is compressed into a thicker
dimension....????

C) Assuming a 1" radial groove in each roller to fully support the
material as it is bent, what should my final outside diameter be for
each roller? The largest bar stock I have at the moment is only 2.5"
in diameter mild steel. If I use this to fabricate the rollers, I end
up with the inner dimension of the roller groove only being 0.5" in
diameter, will this be too small? I figure I'm going to use a 0.375"
shaft to support the bearings, which would not leave much material
between the shaft bore hole and the inner edge of the wheel groove...

D) Finally, using this setup and material, what would be the limits
for the smallest diameter ring I could fabricate?

Thank you for your time!


Take Care,
James Lerch
http://lerch.no-ip.com/atm (My telescope construction, Testing, and Coating site)

Press on: nothing in the world can take the place of perseverance.
Talent will not; nothing is more common than unsuccessful men with talent.
Genius will not; unrewarded genius is almost a proverb.
Education will not; the world is full of educated derelicts.
Persistence and determination alone are omnipotent.
Calvin Coolidge