GWiens2001 wrote:Security pins (at least driver pins) do not affect impressioning to any noticeable degree. Remember that with impressioning, it is the opposite of picking. Security driver pins are affected when the modified portion of the pin is at the shear line. If the driver pin is blocking the shear line, you have cut the key too much.
There are security key pins, and those can affect impressioning. The torpedo pins can lift the pin away from the key blank so no marks are left. Serrated key pins can actually make impressioning easier since the binding effect of the serrations can make the pin mark more clearly.
As for the marks just disappearing, there are three things that commonly cause this to occur for me:
First, when the lock has a cover plate over the keyway causing the key blank to hit the cover plate, the key is unable to move enough in the keyway to make the pins leave an impression. It looks that the pins are marking fine, then fade away. That is the specific reason that I file down the shoulder and spine of the key blank as seen in the post above. Filing those parts, suddenly the pins will start marking again. So now, I always file those parts if the lock has a cover plate. This does NOT apply to locks without that cover plate.
Second, on keyways that are heavily paracentric, such as the twisty Yale and Abus keyways, the marks may seem to disappear, but if you look along the middle of the entire key, and keep in mind that the pins themselves do not move side to side, you can see that the marks may be on the inner edge of the key blade in the curve.
The third cause is also the most embarrassing. Using too short a key blank. Using a four pin blank in a five pin lock, or a five pin blank in a six pin lock. Had one that got me bad when I was making a key for one lock on a lock display board. Yale keyway. Tried and tried to impression a key, and failed. Finally decided to pick the lock and compare the bittings from my impressioned (but non-working) keys to the pin pattern of the picked lock. That is when I found that I was supposed to be using a Y2 (6 pin) blank instead of a Y1 (5 pin blank).Rather than picking it when I figured out that I was supposed to be using a longer blank, decided to impression it with the correct blank. Put in the Y2 blank, turned to apply tension and... pop! Zero bitted.
It happens to all of us. And you should always check the number of pins first.
Master locks can get you that way sometimes. A lock that a M1 key blank fits into may actually use a M10, which is a five pin blank. So check the pin count.
Gordon
Is it possible to impression locks that have serrated key pins ?
