How to Tighten Loose Tuning Pins on a Piano by Pounding
Over time, tuning pins on pianos can become loose due to the wooden pinblock swelling with moisture or contracting with dryness. This eventually causes the grip of the pin to get looser, and frequent tuning and turning of the tuning pin will remount the hole so that it loses some of its torque. In this article, we will guide you on how to tighten loose tuning pins on a piano.
Identifying Loose Tuning Pins
The most obvious way to recognize a loose tuning pin is when you have a sour note that sticks out. Usually, it's gotten that way because the pin has slipped in the pinblock, perhaps during a particularly dry period or day when the block is at its driest. At this point, you need to do something to correct that or you will not have a tuning that will stay.
Checking Eligibility for Repair
Before tapping or pounding loose tuning pins, you have to make sure that your piano is eligible for that particular repair. You can only do the tapping or pounding if there's adequate space between the bottom of the string coil and the cast-iron plate, so the area here of that is above the plate, in this case, it's about an eighth of an inch. You need a little bit of space so that you can tap that pin in without this string coil touching the plate. You do not want the string coil to touch that plate. If you get it down that far and the string coil is slightly binding on the plate when you go to tune the string, it can hang up to the point where it will snag it to the point where it will cause too much build-up of pressure at that point and the string can snap.
Tightening Loose Tuning Pins
To tighten loose tuning pins, you will need a pin setter, a sledgehammer, and hearing protection. The purpose of the pin setter is to place it on top of the tuning pin and give you a clear target to aim your sledgehammer without hitting anything you don't intend to. It also gives you a handle so that you can pull up in a clockwise direction when you hit the tuning pin. This prevents the pin from twisting in the direction that the string is pulling it, which can cause the piano to go out of tune.
Using a sledgehammer, typically a 3-5 pound sledgehammer, hit the pins once at the right angle, and that's all that's necessary to increase the torque. Sometimes, you might need to use a pin punch or be a bit creative to reach the last few pins. You'll start at around 30 torque, and a small tap can often bring it up to double that, to around 60 torque. This is definitely enough to hold the tune quite a bit better.
Tuning pins can get loose over time on older pianos, and identifying and tightening loose tuning pins is an essential part of piano maintenance. If the torque is lower than 30, we recommend this procedure, sometimes just for the bass pins, but sometimes for all 230 or so pins. It's a procedure we recommend doing before tuning to ensure the tuning holds in the long run. It's better to take care of the problem and have good, tight tuning pins so all future tunings will be successful. Remember to use a pin setter, a sledgehammer, and hearing protection for this procedure.
This article is based on the following video from our YouTube channel. For a visual demonstration of the concepts explained here, watch this video: