Sorry - when I said "no cushioning" I meant as in any material that would absorb sharp blows such as may occur when the Centa rollers are undersize. I understand how the HD works (have a newish one on bench in front of me) and how you have managed to keep going with this is great, but perhaps your nut issue is the same as the PB (harder) roller equipped Centa - there is no compliant material to absorb 'sharp' rotational blows?
