Almost finished with the part ... OK , what this part is , it's a sleeve that goes on a motor that runs an oilless compressor . This sleeve needs to be press fit on the motor shaft as it transmits all the torque to the crankpin . The crankpin has a taper that fits into a half-dovetail cut into the sleeve , as the nut is tightened the dovetail locks the crankpin to the sleeve/shaft . I currently have it machined for a .0015 interference fit