How to find the right Clock Keys AI guide

What the AI looks for in Clock Keys

Key size

Clock keys come in numbered sizes matched to the winding arbor's square measured across the flats; measure with calipers or test with a multi-size key set. A loose key rounds the arbor square, which is a costly repair.

Key style

Use crank keys for strong mainsprings (floor and wall clocks) and standard or double-ended keys for mantel and carriage clocks. Crank keys reduce effort and slipping on heavily sprung movements.

Shank length

The shank must reach the arbor through the dial hole without the handle hitting the dial or bezel. Recessed arbors need a longer shank to engage fully.

Construction

Choose a hardened steel or solid brass key with a crisp, well-fitting square socket. Soft or sloppy sockets deform and slip under load.