I needed to bend some coathangers into a specific radius.
This little tool made short work of them.

Laser cut the parts out of 6mm material.
1x base
2x main
2x hinge
2x bolt trap
1x nut trap
1x brace

Use 608 skate bearings with a thin washer in between for the rollers. 8mm or 5/16" bolts for the shafts. I used a 10-24 bold for the adjustment screw, im not sure what metric size would work there.

You will have to glue the main pieces to the base to make it stable.