Originally Posted by
jackbombay
Bigger hammer? Support the bottom side of the pin with a piece of pipe cut to bear against the ground so when you hit the pin with the hammer all the energy goes into the pin and not into compressing tires and the like?
Exactly! Although, I do have a punch set and I know most don't. I think they are essential tools. I have never had a cotter break off like that. Usually they just bend. Well, this saves you the trouble of drilling away the bent part. What I do is center punch the cotter, start with a small drill and work up until the drill is almost as big as the diameter of the cotter hole in the crank. This leaves a centered counter sink in the top of the cotter. Then I drill a clearance hole in a 2x4 and cut it to length so it supports the crank arm against the cement floor. Then using the fattest punch that fits into the counter sink, I drive out the cotter. From the looks of it, you may be able to get away with just supporting the crank arm and driving it through. I like the counter sink because it helps direct all the energy straight through the cotter.
edit: If you don't already have them, I highly recommend new cotters from Mark at BikeSmith. They are the best quality and he custom tapers them to fit Raleigh cranks. On the good side, if you use good cotters and properly install them with the press, you'll never have this problem again.