ring roller

[johnakay]

made this ring roller a few years ago.
its worn out a bit sloppy should I say. the rollers are aluminium (no bearings)
tubing is starting to twist as I roll it.
only need a small radius. the prices of these on ebay is a bit high.
so I'm needing a new one. its only for a 16 mm x 2mm wall .
I dont bend flat bars etc .
so any ideas what might be the cause of twisting as I roll?

 

[Agroshield]

Could the material itself be contributing to the problem? Is it seamless tube or seamed? Is it of known good quality? Is the twisting repeatable and does it have any correlation to the position of the seam? If you were to clamp something to the end of the tube (either on input or output), could you mitigate the twist by applying a counter-torque?

 

[Welderpaul]

If there is slop in the rollers, as the pressure is put on the rolls they tip out slightly, so put a helix into the tube as you roll it.

I had an old ring roller that was terrible for it.