Asked in Mechanical Engineering
How can you get a skeleton key out of an antique door if it is stuck there?
First, if the key is only slightly jammed, wiggling and jiggling it might work it loose. However, I am assuming that if you are asking this question, the key must be good and jammed. If that is the case, the only way I know of is the following; however, it involves destroying the key and therefore, you should be prepared to obtain a new key from a locksmith.
First, hopefully the door is unlocked, or open. If it is closed and locked, you will have to try the following. Remove the hinge pins from the door by tapping them out with a hammer and a centre punch, nail, or other pointed metal instrument. Once the hinge pins are out, try pulling the door away from the frame from the hinge side. You should then be able to remove the door from the frame even if the deadbolt is locked. (Note: This assumes you are on the side of the door where the hinge pins are visible. If not, you will have to access the other side of the door via a window into the room. Good luck!)
Once you have gotten the door open by these means (if necessary), remove the doorknob, then the escutcheon plates (face plates with the keyhole in them). This will expose the hole drilled in the door for the keyhole, and the lock case itself. Now take a pair of locking pliers ("Vise Grips") and grab onto the shank of the key as close to the lock case as possible. Work the pliers back and forth until the key breaks off. Hopefully, the break will occur as close to the lock case as possible.
Now, remove the screws from the edge of the door which hold the lock case in place. You should now be able to slide the lock case out of the door. Unscrew the cover from the lock assembly and extract the broken piece of key, being careful not to disturb any of the tumblers (levers), springs, etc.