Lots of food for thought here and thanks again to everyone for the advice. The nice new bonded plates I bought are too thick so I have gone back to old cork plates with only a little binding and no slipping (so far). One stupid question: do the adjustable plates have pins which bear on the original thrust pins? If so I would need pins, Alan. I have yet to enjoy stripping a clutch completely so I am ignorant of that area. The quick thread does seem in good shape though, plenty of lift.
