Bow (head)The grip of the key; the part outside the lock.
Shoulder (bow stop)Stops the key against the lock face so the cuts line up.
BladeCarries the cuts and millings.
Cuts (bitting)Their depths lift each pin stack to the shear line.
Milling (grooves)Match the keyway's shape so only the right blank enters.
TipGuides the key into the keyway.
Old bit key 2
ShankOn a bit key, the part from bow to bit.
BitTurns the lock's lever or bolt; its cuts clear the wards.
How this list was compiled: Read 2026-09-26. (1) Society of Professional Locksmiths, locksmith dictionary, https://www.sopl.us/locksmith-dictionary.html : bow (the grip or handle), blade (may contain the cuts and millings), shoulder (any key stop except a tip stop; see bow stop), bow stop, tip stop, bitting (the actual cuts of a key; bitting depth), milling (grooves machined along the blade to enter the keyway), shank (on a bit key, the part from the bow to the stop or bit). (2) Master Locksmiths Association, dictionary of locksmith terms, https://www.locksmiths.co.uk/locksmith-terminology-parts-of-locks/ : bow of a key, held in the fingers; cylinder key with a long blade that has V cuts made along its upper edge; key blank not yet notched or bitted. (3) Wikipedia, Lock and key, https://en.wikipedia.org/wiki/Lock_and_key : the bit or blade and the bow; grooves on either side of the blade matching the keyway; pointed teeth and notches called bittings lifting pins to the shear line. Licence: own work
The drawing: Drawn for this site by script, 2026-09-26. Licence: own work
How it works
A key has two ends that matter: the bow you hold, and the blade that goes into the lock. This diagram names the parts of a house key, then the shank and bit of an old-fashioned key.
Read the full guide
Cuts and milling
The cuts along the top edge of the blade, also called the bitting, lift each pin in the lock to the right height. The milling is the grooves along the side of the blade: they match the shape of the keyway, so a blank with the wrong milling will not even go in.
Shoulder and tip
The shoulder stops the key against the face of the lock, so every cut lands under its own pin. The tip leads the blade into the keyway.
Questions and answers
What is the top of a key called?
The bow, or head. It is the flat part you hold, often with a hole for a key ring. Everything that goes into the lock is the blade.
What are the teeth on a key called?
Cuts, or the bitting. Each cut has its own depth, and together they match the pin stacks of one lock.
What are the parts of an old skeleton key?
A bow to hold, a long shank, and a bit at the end. The bit's notches clear the wards inside an old lock as the key turns.