Repair a Broken Key While It's in the Lock

You've broken your key off while in the lock. Now what?

Steps

Using Pliers

  1. With a key that's been snapped off while fully inserted into a lock and if there is a portion of the key sticking protruding from the lock: Try to twist or remove the key with pliers.
  2. Press or pull on the doorknob with the other hand so that there is as little pressure as possible on the lock's bolt. "Feel" when the bolt is free from pressure while turning the pliers, and open or unlock the door.
  3. If a spare key is available, try to pull the broken key straight out. If the key snapped between the lock and unlock position, it will need to be twisted to either position before it can be withdrawn.

Using a Screwdriver

  1. If there is no portion of the key protruding from the lock to grab with pliers, use a straight blade screwdriver (or anything with a blade small enough), inserted or pressed into the keyhole. Press or pull on the doorknob with the one hand so that there is as little pressure as possible on the lock's bolt. Twist the screwdriver to operate the lock much the same way as if the key were attached to the end of the screwdriver, to open or unlock.
  2. Once unlocked, open the door and twist the screwdriver in both directions. Ensure that you can reliably lock and unlock with the screwdriver.
  3. If you're in a hurry, lock the door with the screwdriver and leave. It will probably not be readily apparent that the key is already in the lock, and you should be able to attend to this later on with no one being the wiser - unless someone attempts to use insert a key or it is plainly visible.

Drilling

If at anytime you are unable to open the lock as outlined above, there are only two other ways to open the lock. A locksmith or drilling. The locksmith will do the least (if any) damage but will probably cost the most. Drilling is inexpensive but is the most damaging. Drilling too far could render the lock set unserviceable.

  1. If drilling, the object will be to drill to a depth equal to the part of a key that would normally be inserted into a working lock. Choose a drill bit that will remove the metal from the lock cylinder ONLY. The lock cylinder is the portion of the lock that turns with the key - it is not the handle. Generally, most home locks can be drilled with a 1/4" drill bit.
  2. Once the bulk of the cylinder metal is removed, pry as much remaining metal of the cylinder and pins out so that the mechanism will turn to unlock. Remove the lock set and take to a hardware store to obtain repair parts (new lock cylinder and keys).

Tips

  • Start drilling with a 1/4" bit, as you may not be able to keep the drill in the center of the cylinder. Step up to a larger size only after the 1/4" bit to determine how large a bit can be used without damaging the lock-set.
  • Once you have the time, the lock mechanism will most likely require removal and/or disassembly to remove the broken key. A decent hardware store should be able to set you up with either a new key (bring the broken key) or parts to make the entry set operable.

Warnings

  • Drilling too deep can also damage the lock-set - drill only as deep as a working key would go.
  • Using too large a drill bit can damage the lock-set - drill out only the cylinder.

Things You'll Need

  • Electric drill
  • Selection of drill bits (one 1/4" drill bit minimum)
  • A selection of straight blade screwdrivers

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