Universal Bender
From Pumping Station One
Use
The Universal Bender can take flat stock and make precise round bends. According to the manual, it can also make spiral bends.
There's currently a 1 3/8" bushing, and there are attachments for making other bends.
There's a Fusion file available for 3D printing your own custom bushing which fits over the existing 1 3/8" bushing. When printed with high "shells" so that the filament is printed in circles, it seems to work well. It worked fine for 5mm thick steel.