Much Similar to Tigers suggestion, I normally undercut softjaws provide clearance for the flange guides. Then I bore the jaws for a good fit on the O.D. of the pulley itself. Normally I can bore jaws with a close enough fit to run true. If you do need to indicate, indicate the surface that has a relationship to the feature you are machining. If perpindicularity is called out to the face, indicate the face then machine the perpendicularity to the indicated surface. If you have material on the face you can remove, kiss that prior to removing the part after you have bored it. The perpendicularity at that point would be as true as your machine is capable of cutting (assuming it does not move in the chuck while being cut). If runout or concentricity is called out to the O.D., then indicate the O.D. and machine the bore to it. If you can or need to cut both, do the bore then I.D. chuck or mount on an arbor style fixture and skim the O.D.
Good Luck!
Mark T |