I have to take off a v-belt pulley attached with a Gib head tapered key ,to fit a new Gib Head to the chain sprocket behind it,as the original Gib Head key is slightly worn and gradually slides out. Any tips on on how to remove and refit the Gib head keys, with out knocking the keys in so much that one splits the pulley/sprocket it is holding in place. Also how does on stop the sprocket/pulley moving out of alinement while knocking the key in.Any tips help will be very much appreciated,as I am an amateur with a hammer