As Mike said no details. If the lock is on top like mine,the part that locks on shaft was broken.The part is no longer available from Sears. I dug thru my junk and found a nut that matched threads colet. I cut it down thin enough so when screwed on above colet nut and jambed tight to end of shaft threads ,it does not get in the way of tightning colet nut. You have to hold top of shaft where lock is broken to jamb nut so it will not spin off when tightning colet on bit.