Hi folks,
I'm starting to build an EV modeled after the Hailfire droid from
Star Wars, here's an image:
http://www.starwars.com/databank/droid/hailfiredroid/ . Basically, I'll
need to fashion several separate rolled aluminum/steel extrusion pieces
together to form the 6-7' hubless wheels, and I'm wondering, what kinds
of extrusion are roll-able?
Ideally I'd like to make the rim from several different sizes of
square and rectangular tube to form the lip on the inside needed to
retain the wheel with rollers, but will there be significant rippling
in the walls? Is there some kind of guide to this stuff, or is it a
trial-and-error thing?
-Mike V.

Anybody? I've done some googling, to no avail...

wrote in message
ps.com...
Anybody? I've done some googling, to no avail...


http://www.metalmeet.com/
Try this

The trick to getting oddball profiles to roll well is very good fitting
dies.
So if you are using some wacky profile, you will probably need custom
dies.
The Italians do a lot of custom window frames in very complicated
aluminum profiles, all over southern italy, fitting them into very old
houses with curved top windows.
They use plastic dies for aluminum extrusions- things like Delrin or
UMHW, lathe turned to exactly fit the profile.
With thin wall aluminum tubings and extrusions, it also helps to have a
3 roll powered roll- the cheap hand or motorised rolls usually only
power 1 or 2 of the rolls. With all 3 rolls powered, you can apply less
downward pressure, and get less distortion.
Of course, 3 roll powered rolls cost a lot more.

This is probably not a cheap garage project- depending on the size of
the extrusion, and the size of the finished ring you want, it could run
into serious money. It might well be easier and cheaper to turn these
from solid on a lathe.
I dont know the exact shape you want, but if they are only 6" or 8" in
diameter, and 3/4" finished material diameter, you could probably get
someone with a cnc lathe to turn these for a few hundred bucks.
A decent roll to roll these is gonna run 5 to 10 grand, with custom
plastic roll sets another $500 or so for each size material you need to
roll.

Wait a minute- did you want 6" circles, or 6 foot circles?
6 foot circles, no problem.
In steel, easy as pie.
In aluminum, there will be some distortion, but not rippling, as much
as changing the exact profile out of square- depends on wall thickness-
anything over 1/8" square or rect tubing should roll pretty easily.
Again, as I said above, plastic dies are good for aluminum, because the
metal rolls will scrape up the aluminum. You can always sand it
afterwards. But steel would be easier.

Talk to the boys at Eagle- http://www.eaglebendingmachines.com/
they can fix you up, or at least educate you on how it should be done,
and then you can find a fab shop with the equipment to do it for you.