Stuck and Broken key extraction.
Today I saw a stuck key posting on the UKlocksport forum and it was of interest because only last night I was thinking about the same thing and had decided to make a slide hammer for removing stuck keys and possibly another for extracting broken keys. So off to the workshop again and the end result is a slide hammer for removing stuck keys !. Most keys get stuck because either it did not fit the lock properly (ie a bump key) or not quite enough force can be applied to remove the key. Lets face it the lock is useless if you cannot get the key out so what have you got to lose by applying a little more force in the correct way ?.
The stuck key hammer.
The central object is the brass 'hammer' made from 25.0 mm stock and is an easy sliding fit on the steel shaft, which is a steel tent peg from Poundland. It comes with the hook already formed. I used a 5mm die to thread the right hand end, put the nut on and then peened over the steel shaft, to make sure nothing falls off !.
Make sure the key and the cylinder are vertical, to allow the key to be removed. If the key is stuck at an angle you will not be able to remove it. Place the hook through the hole in the bow of the key. Hold the tool perpendicular to the door (ie straight out in line with the key). Move the brass hammer to near the hook and then slide it smartly down the shaft to strike the stop on the end of the tool. Hopefully the key will pop out of the lock, leaving the lock functional.
Broken key extraction.
Broken key extraction involves sliding a very thin tool between the key stub and the cylinder wall. To work the tool has to have at least one tooth on the end of it that looks something like the barbed point of a fishing hook. The hook catches on any part of the key stub and is pulled out. It is possible to make ones own extractors from fret saw blades. Break the blade in half and using the half with the teeth pointing towards you, grind the broken tip into a point, to help it enter the gap between the key and the cylinder. This space is very small and by turning the tool slightly the teeth will bite into the keystub making it possible to slide both the tool and key stub out of the lock together.
Highly magnified photograph of various fret saw blade broken key extractors. The second one down has had all teeth ground off except the one on the end. The beautiful thing about making your own tools is that you can have the very best that suits you. Notice the slight up curve of the point which helps force the tip between the key and the cylinder in order for the teeth to bite into the broken key stub.
The blades are too fine to be used in the fingers so I made a handle for them. Below is a picture of the handle, with blade fitted against a hook made from a standard windscreen wiper blade. Fret saw blades much thinner than those shown are available. Remember that with patience and saliva ... the elephant can mount the ant !.
When everything fails.
Gain entry by other means, slip and remove the lock cylinder, carefully remove the C clip, remove the tail and punch out the stub from the back, through the front of the cylinder. Then promise not to do it again !.
To be continued .......
Copyright John 'Magic' Kent 2011.