WHAT CAUSES KEYS TO BREAK
Most keys, even brass and nickle-plated keys, will eventually wear out and break along any of a key's cuts. But some conditions will speed up the process such as:
1. The key has one or more deep cuts which become the "weak point" of the key. After so much use (or just a little abuse) the key will break at these points. Having a deep cut as the first cut (next to the head of the key) can be real trouble but a deep cut in the middle of the key can cause big problems too;
2. The key is made of a light-weight material not suitable for everyday use. Keys cut on aluminum blanks are a prime example. They will also break at a deep-cut "weak point" only sooner. Identified by their light weight and either grey in color or sometimes bright colors such as red, green, blue or gold.
Usually before a key breaks, one or more tiny cracks will appear by the cut about to give way. You may want to check your keys right now - at least the ones that you use and depend on every day. If you see a tiny crack being formed by one of the cuts or if the key is bent or misshapen in any way, go to your nearest locksmith or key shop and get another one or two made. And just to be safe, don't carelessly toss the old key away. A new key could be made from the pieces and used to access your property.
BROKEN KEY REMOVAL TOOLS
We locksmiths have a variety of tools for removing broken keys from locks. One of the more common tools I use is made of springy steel that is 5" long, 5/16" wide at the handle and .022" thick. There is a small tapered barb at the end of this tool that will dig or "bite" into the broken key piece so the piece can be pulled out.
It is not absolutely necessary to invest in a broken key extractor tool. As long as the tool you use is made of sturdy metal, is narrow enough to enter the keyway, and has a barb to grab on to the broken key you will likely be successful. A scroll saw or jig saw blade should do the trick.
PROCEDURE #1 - Partial Key Broken Off In Lock
When a deep cut gets too weak somewhere in the middle of a key, you end up with the front part of the key in the lock and the remainder in your hand. The good news is the lock is probably in the proper position for key removal (more on that later).
FIRST - unless the lock has been in good working order (with the key going in and out smoothly) prior to the key breaking off, I suggest spraying a lubricant such as WD-40 or Tri-Flow in the lock's keyway first. You want the broken key piece to slip out as easy as possible and a dry or gummy lock will make the job harder.
SECOND - insert the removal tool into the lock's keyway so that the barb (or teeth) can contact the cuts of the key piece to be removed. You should be able to tell how far to insert the tool based on how much of the key you still have in your hand.
THIRD - let the barb "bite" into one of the cuts of the broken key piece and give the tool a sharp tug towards you. The key piece should come flying out.
FOURTH - take the two pieces of the key to your local locksmith or key center and get another one or two made.
PROCEDURE #2 - All But Key's Head Broken Off In Lock
When the first cut in the key is deep and gets too weak, you end up with just the head of the key in your hand. Most of the time what remains in the lock is the operating part of the key. That is, all key cuts that are necessary to operate the lock are stuck in the lock (if you are really lucky, enough of the key will be sticking out so a small pliers/tweezers are all you need to remove the broken piece-but that usually doesn't happen). You can test if the lock will operate by taking a small screwdriver and, using it like a key, try turning the lock cylinder. If the lock cylinder does not turn follow procedure #1. If you can turn the cylinder more than a few degrees to the right or left you have to make sure the lock cylinder is positioned so the key can be removed. Let me explain...
Most locks have one position that a lock cylinder must be in for key removal. If you were to insert a key in most any pin tumbler lock and turn it, the key could not be removed until the lock cylinder is back in the proper key removal position. The same is true when removing a broken key piece that still works the lock. The key cylinder must be in its normal key removal position or you will be wasting your time trying to remove the broken piece.
FIRST - as in Procedure #1, we suggest spraying a lubricant such as WD-40 or Tri-Flow in the lock's keyway first.
SECOND - insert the removal tool into the lock's keyway so that the barb (or teeth) can contact the cuts of the key piece to be removed. You should not have to insert the tool very far - just so it reaches the first or second cut of the key piece.
THIRD - let the barb "bite" into one of the cuts of the broken key piece and give the tool a sharp tug towards you. The key piece should come flying out of the keyway.
FOURTH - take the two pieces of the key to your local locksmith or key center and get another one or two made.
Now that you have read through this information, you should be ready to attempt removing a broken key on your own. Good Luck!
NOTE: This article (with pictures) can also be found on my web site www.GoldKeySelect.com/brokenkey.html
Roger J. Fischer is a security professional with over 25 years of experience in providing security solutions for his customers. For more articles related to security, safety and a variety of other topics visit http://www.GoldKeySelect.com