I'm going to make up some re-purposed (used) Ultegra 6500 crank arms that have damaged anodizing and the one key release crank bolts are messed up. For a fresh look I would like to use some aftermarket Octalink bolts. I was wondering what metric size these are? And if they are the same ones that are sold for Isis cranks. Thanks for any help. I like these old Octalink cranks and would love to give mine a new purpose in life.