Clutch cover question.

[john charlton]

A friend had clutch troubles and asked if I had a good used clutch pressure plate . I selected a good one and mounted it as a test on a model "B" flywheel using a new disc . All fingers were even at 3/4" so near enough should be 5/8". Fitted this cover to his flywheel and had over 1" finger clearance . Finally did find another pressure plate which gave 3/4" so good to go . My question is if a flywheel is machined to clean it up does this make the fingers more in or out ? My 84 year old brain cant compute on this ! Many thanks to Gurus on the famous " Barn ".

John in lovely warm sunny morning Suffolk County England .