Have you ever tried bending a metal rod into a consistent curve? Maybe you bent it over your knee or broke out a bucket or something. Doing it by hand never really gets the arc perfect. Handyman [Joe] found himself needing to bend a bunch of 1/4″ metal rod into various diameter rings. He didn’t have any tools to bend or roll metal and instead of fretting about it, he put on his ingenuity hat and built a perfect tool for the job.
That perfect tool is called a Roll Bender and it uses 3 rollers to bend metal into an arc of consistent radius. The straight piece of metal is passed by the rollers many times. The distance between the rollers is continually adjusted to reduce the radius of the arc of the metal until it reaches the correct size.
[Joe] started out with an old drill press vise. A piece of plate steel was welded to the stationary vise jaw to provide a platform for a grooved pulley to be mounted. On the clamping jaw, a piece of angle iron was attached to support two very large bearings. The metal rod is clamped between the two bearings and the grooved pulley. A key made from a socket and some scrap metal as a handle allow the user to rotate the pulley by hand while the distance between the rollers is adjusted by the vise’s crank. Doing this moves the rod back and forth between all 3 rollers to gradually mold the once-straight rod into a full ring.
We’ve always been fond of machines that do the bending for you. Even if they haven’t been invented yet.
Only thing missing from that bender is that it is not powered by a 6502 processor.
Bwbbbbahahaha!
This is brilliant and I’m going to build one with a spare 10″ drill vise I have, that’s too big for any drillpress I have right now.
With that said, hand-bending can be quite adequate. If you cut a bending form out of plywood and bolt it to your workbench, and account for springback, you can do 1/2″ square steel tubing with ease, and end up with any weird outline you want (if you’re careful with planning the sequence of bends, you can do convex/concave curved sections.)
But man this is sweet for creeping up on an exact bend radius without all the uncertainty of springback.
Great idea!! I’d be tempted to put a proper hand crank on the big pulley. Of course since nothing’s finished until it’s been modded to death, a geared down motor would be great too.
and there’s the commercial version of it.
https://www.youtube.com/watch?v=mWJwGHd4RzM
$470! I think the homebrew wins…
er, you know those vise’ aren’t cheap right?
esp teh milling vise’