Not only is breaking a key of in a lock cylinder a frustrating experience, it can also be quite costly. The average cost of a locksmith visit can run from £32 to £48. Not only do you have to shell out money for an unexpected expense, but it might take hours or even days before the locksmith can fit you into his schedule. Removing a broken key from a lock cylinder requires a steady hand and a bit of patience, but it is well worth the time and financial savings you will reap.
Spray the lock with WD-40. This will make it easier to slide the key out of the lock. In addition, try to warm the lock with a hair dryer before pulling at the key.
Grab the end of the key with a needle nose pliers and try to pull it out of the lock, if possible.
Determine the location of the key teeth within the lock.
Insert the saw blade into the key hole along side of the key teeth. Try to grab the key teeth with the teeth on the saw blade. Once they catch, slowly pull the blade out of the lock. If the blade only moves a small amount, try pulling with the pliers again.
Insert a dental pick into the lock cylinder. Try to catch part of the key teeth with the pick and slowly pull the key out.
If the key seems jammed and won't pull out of the lock at all, examine the cylinder to ensure that it is not turned past the initial key entry position. If it is, readjust the cylinder by giving it a jiggle and try to pull the key out again. If the key is lodged in a door knob and you have access to the inside of the house, you might consider replacing the door knob. This is much cheaper than calling a locksmith.