Lesson 2: Tools, Locks, and Keys - Part 3

How To Identify A Key

One of the most important things to know when you are becoming a locksmith is how to identify keys. Cutting keys is the most basic task a locksmith can do. Every good locksmith can identify most keys from a few simple signifiers. Understanding the individual components of a key is the best way to be able to identify a key.

Head or Bow:

The head or bow of a key is the part that you grip with your fingers. The head is also the place to look for additional key data such as the manufacturer’s code, which will aid you in identifying the key. The shape of the head often varies depending on the manufacturer; however, many different types of keys share the same style of head. As a result, the head of a key is often not a reliable means of identifying a key, although becoming familiar with common key shapes is an important part of be able to identify key types.


The shoulder of a key or key blank is the projection found between the bow and the blade. Most keys have two shoulders, but some keys have only one, and some have none. The purpose of the key shoulder is to stop the key from penetrating too far into the lock mechanism, ensuring that the biting is aligned with the pin tumblers inside the lock. If you were to force a key beyond its natural depth, it wouldn’t work; it could also damage the lock. The should ensures that the key fits into the perfect position every time.


The blade is the longest portion of a key where the locksmith cuts the distinctive pattern of notches that will turn a blank into a working key. You may sometimes find manufacturer’s data on a key blade instead of the bow.


The cuts or notches made in the blade of a key are referred to as the biting. These cuts align according to the depth of tumbler pins in the matching lock. The biting must be cut precisely in order to allow the key to work in a lock.


The tip of a key or key blank is simply the end of the blade. The key profile can be found by looking at the narrow edge of the tip.


On a key blank, the milling refers to the grooves engraved into the blade. Note that, typically, both sides of the blade are grooved. The milling determines the key profile.

Keyway Profile:

The keyway profile can be found by looking at the narrow end of the tip. The profile determines which locks and keys can interact with each other.

Now that you have taken some time to understand the components of a key, try identifying each of the components on the diagram below. Please note each individual component and what is significant about it.

For the layman who can’t determine the identity of a key by glancing at the keyway, milling, or tip, the best way to accurately assess key identity is by looking at the small numbers in the bottom corner of the head of the key. The number is somewhere close to the shoulder, and is usually a combination of letters and numbers. A conventional Weiser lock might say “WR3” or “WR5,” a standard Schlage key would say “Sc1.”

See the chapter one reference section for the necessary content required to identify key manufacturer codes.