Expanding MIG Roller Bore

[eSCHEn]

I wonder if a stiffer strip on the top roller adjuster might help? (3mm thick, piece of cut down angle iron) I know it needs to give a bit but with care (not over tightening to the point of bending the bottom roller shaft) it may give a more positive (rather than over) pressure. Could even fit a strong spring under the tension spring to still have a bit of give.
You might have polished the groove up to much!

I tried to keep the grooves with some traction but to be honest Mike it's working now and that's as good as it's gonna get for me It seems crazy they'd cost cut by not knurling but there you go. The clarke roller is infinitely better designed.

They don't need to be particularly tight, how long is the lead on your torch? All the 4m torches on our welders at work have twin drive rollers.

3m, Steve at weldequip advised not going any longer and I'm glad I didn't. The original was 2m and I think three's as much as it could push.