De Fang your keys

This page explains how to smooth your keys so that they do not cut holes in your pockets.
It only applies to the ordinary pin tumbler keys that have a row of 'V' shaped notches on one edge. This does not work on those double edged ignition keys or to the square notched lever tumbler safe deposit box keys or any other kind of keys.

The key will continue to function correctly even after the points are cut off because the lock is operated by the bottoms of the notches; not by the projecting points in between. The pins (also called 'tumblers') are in two parts and various lengths. When the key is out springs push the pins down so that they cross the joint between the lock's core and shell and prevent the core from turning. With the correct key in place the pins rise and then sink into the bottoms of the notches and all the joints line up so that the lock can open.
Here are just some of the many reasons why keys have sharp points on them:

• They limit manufacturing costs by reducing the amount of metal that must be removed from the key blank.
• They cut holes in your pocket.
• They protect the bottoms of the notches from wear.
• They make the lock's pins jump up and down so that they wear out faster.
• They make the key look more complicated and secure than it really is.
• They hold the key in the lock while it is turned even if all the pins are the same length.
• They make a nice crunchy sound in the lock.

Few of these advantages are good for you.

Step One: First make sure that you have a spare key. A spare key that works. A spare key that you have personally tested. A spare key that you can definitely rely on in case you screw up.

Step Two: Clamp the key in a padded vise with the points showing. Get a good sharp fine file and cut off all the points so they do not saw holes in your pocket. Take care not to touch the bottoms of the notches! Leave just a bit of metal projecting above the notches to protect them from damage. See 'A' in Figure 1. The notches are equally spaced, so if you see a flat topped bump where a notch should be leave it alone; it's a notch. Bevel the sharp little hook at 'B'. Round off the tip of the key so it enters the lock easily and does not poke a hole in your pocket.
Do not screw up.

Step Three: Cut off all the sharp edges with a piece of fine sandpaper. About 320 grit or so. Just a quick rub will do. Further polishing is unnecessary; normal pocket wear will take care of that for you.

Step Four: Clean metal chips and dust off of key. Stick key in lock. Feel how easy it goes in. Turn key.
Tug on the key to see if it comes out while partially turned. If it does that means that all the pins are the same (or descending) length and the lock is easy to pick and no good anyway.
Here are before and after pictures.

Here is what to do if you screw up: No problem! Just duplicate your spare key; the one that you made sure that you had in Step One; and start over.

Here is what to do if you screw up and do not have the spare key that you did not make sure you had in Step One: CRY.