This is a play on words, BUT your front shaft has to be attached to a disk at least say 5/8 inch thick with a  hole in the middle to clear the bolt holding the front pulley on and the shaft then attached to this disk. There are threaded 3/8 inch holes in the pulley hub, therefore you are not actually bolting to the thin part.  What size Vickers are you thinking of using? The reason I asked your shaft has to handle the torque load of the pump. Questions?