What Is In The Pin Tumbler Lock Cylinder On My Door?

Pin Tumbler Cylinder

Pin Tumbler Cylinder

I’ve been asked by relatives, friends and clients what is inside the lock cylinder on their door and how does it work? When I provide a lock rekey service I invite the client to witness the process of changing the key that operates the lock on their door.

There are many small parts that work in concert with each other that allow the key to operate your lock. I would like to relay to you that improper disassembly of a pin tumbler lock cylinder can be very unforgiving. I do not recommend that anyone attempt to disassemble the lock cylinder of their lock without the proper tools and knowledge. If you don’t know how the cylinder is assembled and you decide to take it apart, chances are that you will have many small parts flying around your room. You will be really fortunate to find every last part that flew out of the lock cylinder let alone putting it all back together properly so it will once again function with a key.

Standard Pin Tumbler Lock Cylinder  

The lock cylinder (see diagram) is the heart of the lock. It accepts your key and enables the bolt or latch to be retracted or extended. The two main parts that make-up a lock cylinder are the housing and the plug (see diagram). The plug is the portion of the lock cylinder that accepts your key. It is also where the bottom pins reside that correspond with the cuts in your key. The bottom pins are flat at one end and come to a point at the other. The pointed end of the bottom pin is what sits in the cuts of your key. The housing encompasses and houses the plug along with top (or driver) pins and a spring. The top pins are flat at both ends and are driven into the bottom pins (With the aid of a spring behind them) in order to push the bottom pins into the keyhole (the proper Locksmith term for keyhole is keyway).

When the correct key is inserted into the lock cylinder plug keyway, the bottom pins are raised to the correct level and the plug can turn. At the back of the plug is one of several different devices all used to actuate the bolt. It really depends on the design and application as to what will be found at the rear of the lock cylinder plug. If it is a standard type deadbolt then there will likely be a lazy tailpiece that actuates the bolt. If it is a mortise lock (found in many storefront door applications) then there will be a cam found on the back of the plug. When the correct key is inserted and the plug is turned this actuates the bolt or spring latch behind it by moving the lazy tailpiece or cam.

Security Article Written by: Toronto Locksmith



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