Fixing Loose Tuning Pins by Pounding
Tuning pins can get loose over time, usually on older pianos. As the wooden pinblock swells with moisture or contracts with dryness over the years, it eventually causes the grip of the pin to get looser. Also, frequent tuning and turning of the tuning pin will remount the hole so that it loses some of its torque. A new piano may have a torque reading somewhere in the range of between say, at least hopefully 80 to 120, maybe being a good tight torque can go up higher than that, 150. But as pianos age, you'll find them probably down between 50 and 70 often times, and that's still a decent range where the piano will hold its tune. When you get down to 30 and below that, you'll get to eventually to a point where the pin simply will not hold the tension that the string is putting on it by pulling it and twisting it.
The most obvious way you will recognize a loose tuning pin is when you have a sour note that sticks out, something like this. You can hear that the unison is way out of tune. Usually, it's gotten that way because the pin has actually slipped in the pinblock, maybe during a particularly dry period or day when the block is at its driest, so the pin actually moved. At this point, you need to do something to correct that or you will not have a tuning that will stay.
I'm going to demonstrate on this piano in the bass section because the bass section is often the first section that you will find loose tuning pins. It's just, I guess, there's more pull down here on these thicker bass strings or maybe the pinblock is a little thinner than it is in the treble and midsection, but for whatever reason, this is where you'll often find the loose tuning pin problem first.
When we go to correct loose tuning pins by tapping or pounding, 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.
If the pin has been pounded already, there may be no space here, but on a new piano, usually, the pins are about 3/16 of an inch above the plate at that point, and you have at least a sixteenth or an eighth to pound them in. So, there is enough room to pound, and it just takes a little bit to tighten these pins. Often, I'll just have one good pound will do the trick, and I drive them sometimes even less than a sixteenth of an inch into the pinblock. But for this, it is very good to have this pin setter, and it's made for this purpose.
The purpose of this tool is to do two things. First of all, you can place it on top of the tuning pin, and it gives you a clear target to aim your sledgehammer without hitting anything you don't intend to. The other thing this tool does is give 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. If you were to use a punch without the handle, you'd end up with a piano that is way out of tune because the pins will slip and let go as you hit them, since they're already loose. This is a great tool to have, and I'll demonstrate how to use it now.
I use a sledgehammer, typically a 3-5 pound sledgehammer, to hit the pins. I recommend using hearing protection when doing this. You have to 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.
If I have a piano and the torque is lower than 30, I will recommend this procedure, sometimes just for the base pins, but sometimes for all 230 or so pins. It's a procedure I 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 hold, and you'll look better for it.
If you have any questions about this procedure, you can ask them in the comments, and I will respond to and answer them as best I can. Our website is howardpianoindustries.com, and you can see the link below. Thank you for watching.