Keyed alike is the term used to describe multiple locks having the same cut so that one key can fit all the locks. Having your locks keyed alike is the most convenient way to handle and manage all your keys.

The earliest patent for a double-acting pin tumbler lock was granted to American physician Abraham O. Stansbury in England in 1805, but the modern version, still in use today, was invented by American Linus Yale Sr. in 1848.

To make a new key for an existing lock, you cut a series of notches in the key so that it raises each of the upper pins just above the shear line. Essentially, you cut a pattern in the metal that matches the pattern of the pins in the lock.