What Is Lock Impressioning?

Lock Impressioning Kit

To say the very least, Lock Impressioning is an art form. It is a technique for making a key where there currently isn’t a key. When a professional locksmith technician impressions a lock, he or she is making a key for a lock with nothing more than the proper key blank, a sharp and very fine type Swiss round file and very fine emery cloth. The file is preferably Swiss made because they are the very finest for the purposes of impressioning. A locksmith will also employ some very fine emery cloth and a small pair of ViceGrips.

Many clients are amazed when our locksmith manufactures a key by impressioning a lock. In some instances where it is found to be difficult to pick open a lock, then impressioning can be used to manufacture a key that will work the lock. Another example of the need to impression a lock would be where it is almost impossible to remove the lock to make a key. There are some file cabinets where the lock has been placed in an awkward spot. It is actually easier to impression a key than it is to take a large portion of the cabinet apart to get at the lock to facilitate making a key.

Two of the most common locks found today are pin-tumbler type and wafer type locks. The impressioning technique is the same for both types of locks with the exception of the preparation of the key blank. For those who don’t know, a key blank is simply an uncut key. The key blank has a head and a blade. The blade of the key blank needs to be properly prepared With both types of locks.

With a pin-tumbler type of lock the top of the blade, (where the cuts of the key would normally be found) needs to be properly prepared. A locksmith will use a fine piece of emery cloth in order to shine up the top of the blade to a mirror finish. The whole reason for this is so that it is easy to spot the marks that will appear on the top of the blade as you start to impression the lock.

Once the top of the key blank has been prepared, clamp down on the head of the key with the small visegrips making sure that it is tight enough that the visegrips will not move around on the key head. Insert the key blank all the way into the lock, right up to the key shoulder. Using only your thumb and index finger gently bump the key up and down in the lock while applying a light turning pressure in both the clockwise and the counter clockwise directions. Bump the key back and forth several times and then remove it from the lock. Have a look at the top of the key shank and you should be able to see some round dots impressed into it. The whole idea here is to bump the key up and down and then file where you see the marks on the key shank. You may see 5, 6 or even 7 points impressed into the top of the blade. You need to file everywhere that you see a mark. When you can no longer detect marking on the key shank, stop filing! As you go through this process of bumping and filing you will notice that the key is starting to turn in the lock. By the time you are done, and hopefully you haven’t continued to file where there were no marks, eventually you will end up with a key that will operate the lock.

The only difference in key blank preparation between a pin tumbler lock and a wafer type lock is that you would knife edge the shank on the key blank as opposed to shining it up for use with pin tumbler type locks. A wafer lock usually leaves more pronounced markings that can be seen across the width of the blade usually in each position that there is a wafer. There could be 4 or 5 markings on the key shank. As stated previously, file where you see a mark. When you no longer see a mark then stop filing. Eventually you will manufacture a key that works.

Security Article Written by: Toronto Locksmith



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