Far too often I have seen cylinders rekeyed incorrectly. I’ve seen this in person and online, specifically on YouTube. The incorrect rekeying process typically goes like this:

  1. Remove the cam/tailpiece.
  2. Remove the plug with a follower.
  3. Dump the old bottom pins.
  4. Install new bottom pins.
  5. Re-install plug.
  6. Re-install cam/tailpiece.
  7. Lubricate.
  8. Check operation.

What’s missing? Perhaps one of the most vital steps of all: checking the ‘bible’.

The Bible

We covered the ‘bible’ in Locksmith Terminology: Pin Tumbler Cylinders but to recap:

bible n. that portion of the cylinder shell which normally houses the pin chambers, especially those of a key-in-knob cylinder or certain rim cylinders

The bible for KIK/KIL, mortise, and rim cylinders houses the top pins and springs. In the above scenario, no attention is given to it. Why should there be?

Potential Problems

There are quite a few items related to the bible that every professional locksmith should be concerned with:

  1. Springs. Are the springs crushed or weak? If so, there’s a very good chance that the cylinder will operate intermittently.
  2. Top Pins. Are the right top pins being utilized? Manufacturer’s specifications are not friendly suggestions. Has someone inverted bottom pins to account for a prior, poor rekeying job? That removes a tremendous amount of pick-resistance.
  3. Potential Master Pins. Are there any master pins in the bible? Whether you disassembled the cylinder with a key or via shimming, the potential exists for master keys to rest above the plug and within the bible. With that comes the potential for incidental master keys.

incidental master key n. a key cut to an unplanned shear line created when the cylinder is combinated to the top master key and a change key

There’s also a chance that debris, such as dirt or excessive graphite, has worked it’s way into the chambers. That too could cause intermittent operation or failure.


Once you touch that cylinder  you “own it”, so to speak. If something goes wrong, you were the last person to touch it and you’re more than likely going to hear about it first. Avoid the headaches and liability by doing things right from the start. Rekeying isn’t simply replacing the bottom pins. A professional rekey job also includes inspecting what’s in the cylinder’s bible; a process that only takes an additional 10-15 seconds. It also includes correcting any mistakes the last person to touch it made. If those mistakes are beyond reasonable correction, a professional alerts the customer and makes the recommendation to replace it.

Here’s another way to consider it:

A call back results in what? An hour of your time? If we assume 10 seconds to check the bible, that means you can check 360 cylinders during that time, albeit broken up and over time. If you ignore the bible all together, you’re essentially gambling that at least 360 of the cylinders you touch aren’t going to have any of the aforementioned problems present AND those problems won’t result in a callback. On the 361st cylinder you touch, you’re coming out ahead by a whooping 10 seconds. See what I’m getting at? An ounce of prevention is worth a pound of cure.

Checking The Bible

You can complete the process of checking the bible in just a few seconds. Here are two ways you can do that: