Fixing a lock that won't let go of its key

Question: I own a commercial store and have been having problems removing my key from the lock. The key goes into the lock fine, however when I go to remove it, I have to push and pull for ages before it comes out. I'm afraid that one day, I won't be able to get my key out. How can I fix this problem?

Fourchalk: My advice to you is to phone a locksmith immediately! You mentioned that you own a commercial store. Chances are you have a lock that is operated by a mortise cylinder. The mortise cylinder is the part of the lock that accepts the key. On the back of the mortise cylinder is a cam (or lever) which engages with the deadlocking bolt and either opens or closes the bolt, depending on which way you turn the key.

Your problem is related to the fact that the screws on the back of the cam have worked their way loose. This is usually caused by pulling the door open with the key. This loosens the cam over time and does not allow the key to be removed. If you do not get this problem fixed, the mortise cylinder will eventually fall apart, leaving you with a handful of springs and pins. So call a locksmith who will remove the mortise cylinder from the lock and install new screws (with locktite) to hold the cam in firmly again. And remember to open the door with the handle, and not the key!