I made this circle guide for my bead roller. The silver part is a steering pivot from an old kids quad, the hex head bolt spins on 2 bearings and has a m6 tapped hole to secure the work piece. You need to have a 6mm hole in the centre of the circle. Then it's adjust it to the desired radius and clamp your dies and give it a few turns.
So your kids have now got a lopsided trike?......... "It still works fine kids...... Just don't turn left, OK". LOL !
I've done the usual strengthening upgrades aswell as a sliding clamp that I want to add a fence to for rolling parallel to the edge of a sheet. I'm also going to fit some sort of power feed to it once I acquire a suitable motor.
I put a sliding fence on mine and it helps to give nice straight lines (if the lines are square to the edge that is). It helps to keep the sheet square and cut to size after the beads are run. I motorised it as well and it's a great job.