[originalowner]

You all should realize that the more you file, the more keys that will operate the lock, and the easier it is to pick. At the point you have the cylinder out, you should take it to a locksmith who can cut a key to fit, so only one key pattern will operate the switch. If you are extremely lucky, the tumblers can be rearranged to fit your ignition key (but unlikely.) The locksmith may have tumblers that fit the cylinder, which can be swapped in so that it does fit your ignition key, and only that pattern. A few bucks, and far more secure.