What Does a Rebanking/Knocking Watch Movement Mean?

What is rebanking in watches?

Rebanking or knocking (sometimes referred to as knocking the banking) occurs when the pallet fork horns (prongs) hit the impulse pin. Here is how the dictionary defines it:

“A malfunction in a watch caused by excessive balance motion that makes the roller jewel strike outside the fork horns and renders the escapement inoperative —distinguished from overbanking” –source

What does rebanking sound like?

The quick video above gives an audible example of what it sounds like when a watch movement is rebanking or knocking. Some say it sounds like a horse galloping.

How can you diagnose rebanking?

High amplitude can result in rebanking or knocking. Since an amplitude of 360 degrees means that the wheel is making a full rotation, causing the impulse pin to knock into the pallet fork.

What causes this to happen?

Rebanking or knocking can be caused by a few different things: incorrect parts (such as too powerful of a mainspring), lubricant viscosity, bent banking pins… are some of the culprits. If you feel that your watch is rebanking and don’t know what you’re doing, then it’s time for a professional inspection and possible service.

Rebanking vs Overbanking:

Rebanking and overbanking are not the same thing and these terms are not interchangeable. Overbanking is when the roller jewel finds itself on the outside of the pallet fork. An overbanked watch doesn’t run. As with issues mentioned above, some overbanking causes could be incorrectly positioned safety/guard pin on the pallet fork, pallet jewels, incorrect roller table placement, etc.

How is a ticking watch supposed to sound?

Below is an interesting video with more of a visual of how the sound of a ticking watch is created on a Swiss lever style escapement:

Some watches are quieter than others depending on the movement or the case design. If you want to hear your watch ticking more clearly, you might enjoy owning your own timegrapher machine. A timegrapher has a sensitive microphone which picks up the sound from your watch’s movement, then runs the beat through software which displays it on the screen for tasks such as easy diagnosis and assistance in regulating the rate.

Have you had a watch with rebanking or knocking? Please share your experiences and fixes in the comments below…