Piano key sticks or doesn't return

Symptoms

• Key stays pressed down after playing
• Key feels slow or sluggish compared to others
• Key rubs against its neighbors
• Sticking is worse in humid weather

Likely causes

• CommonDust, debris, or a dropped object under or beside the keyCrumbs, hair, or small objects between keys are the most common cause of sticking.
• CommonHumidity swelling the woodWooden key parts expand in humid conditions and can rub against neighboring keys or guide pins.
• PossibleA bent key guide pinThe small pins that keep keys aligned can bend slightly from a heavy-handed player or an impact.
• PossibleWorn or swollen key bushings (felt)The felt bushings that guide key movement can compress or swell over time, causing binding.
• PossibleSticking hammer or action part (grand or upright interior)Inside the piano, an action part can bind due to dirt or a worn part, which needs a technician.

What to do

1. Look between the sticking key and its neighbors for visible debris, and remove anything you can see with tweezers or a thin card.
2. Press the key gently and watch how it moves compared to keys on either side to see if it's rubbing at the top or leaning sideways.
3. Run a thin piece of paper or a business card along the sides of the key to check for tight contact with its neighbors.
4. If the room has been very humid, run a dehumidifier or air conditioner near the piano for a day and recheck.
5. Avoid forcing or prying the key, which can bend guide pins or damage the wood.
6. If it's an upright piano, note whether the sticking key's hammer looks stuck when you look inside with the top open (do not touch the action).
7. Keep a note of which key and how often it sticks if you need to describe it to a technician.

Tools and parts

• Tweezers
• Thin card or paper strip
• Flashlight

When to call a pro

If removing visible debris doesn't fix it, or the key still binds, call a piano technician; the action mechanism is delicate and easy to misalign without training.

Safety