av8tor: I know there is a center in the end of crank already. If you use that center you will have drill .625 or 5/8 of a inch further. The further you drill the more chance of getting off center. May be best to cut off threads grind flat and use a new precision center drill which I have 2 of. Maybe a #21 pilot drill like RCIGN1 recomended. I do not know if fine threads would be best or coarse threads? You never did say what you are going to do about the taper? Capt,n