Why Do Keys Stick?

Sometimes people call to get their piano tuned simply because they have a key that is sticking. They are often willing to live with the piano being out of tune, but a sticking key is too frustrating, so they call for a tuning and repair appointment. So, what are the culprits of a sticking key?

Culprit #1: The Key

The first thing that could cause the key to stick is the key itself. The key needs to be able to freely pivot down and back up when a person depresses it. It might not for many reasons, including the key bushing felt being too tight, the position of the keyslip or adjacent keys, or even foreign objects that have accidentally fallen into the piano.

Culprit #2: The Whippen

The whippen is a complex part of the piano, and it is very different in upright pianos compared to in grand pianos. The whippen is directly set into motion by the key. There are many different issues related to the whippen that could cause a piano key to stick. For example, a spring could be broken, springs could be lacking tension, center pins could be tight/sluggish, or alignment issues between the "jack" part of the whippen underneath the hammer. It's very common for some kind of whippen issue to cause a sticking key.

Culprit #3: The Hammer

The last step needed for the note to play is the hammer to bounce off of the strings. But the hammer might not be freely rotating forwards and backwards. Thankfully, this, like the other culprits of sticking keys, is not difficult to fix after gaining the knowledge and understanding of how to correct the problem.