Diagnosing the Sticking Piano Key (Piano Tuning and Repair)
Welcome to our Series on Piano Tuning and Repair.
One of the most common issues with pianos is having a sticking key. There is a list of things that could cause the sticking key. The video above walks you through the steps of checking the most common causes of a sticking key. Once you have determined what the cause is you can then move forward with the right solution or repair. We offer the parts and tools needed to make piano repairs in our online store which can be found at the address above.
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Video Transcript:
One of the most common issues in pianos are what some would call a sticky or sticking key. That particular symptom or what some would call a sticking key, there could be a number of different reasons that could cause that problem. This video will go through some of the more common or major things that you would come across that would be solutions to fixing a sticking key. It's not just necessarily always one thing that is causing that. This will kind of walk you through the steps to check if you have a sticking key to figure out what the problem is. Now we are going to start at the front of the key here.
Piano Keyslip
Probably one of the more common and easier to fix problems is often times if it's just white keys that are sticking. It could be that this board right here that sits in front of the keys which is called the key slip. This could be too close to the front of the keys.
So what happens is if this is too close when you push the key down, it gets stuck. The front the key gets stuck up against the key slip. You can kind of tell that if you look down in between the front of the key and the key slip. You can see that there is no space there.
The other thing is if you just pull back just a little bit and the key comes up then you know that the key slip is too close. The way to fix that is to take the key slip off. There are some screws under here or sometimes they just slip right off. Most of the time in most cases with the upright or vertical piano, they have screws underneath the key slip that you take out , and then the key slip will slip off. Then what you do is put a little shim to figure out where it's the closest. You can just make a shim out of either a piece of thin cardboard or something. You can ever tape it to the key frame. Then you put that up there to push the key slip out just a little bit because it doesn't have to be very much.
Just enough so that there is a little bit of space between the front of the key and the key slip. Now that is the first possibility.
Key Bushing and Key Pins
The other thing is that I have taken some the keys out here. It could be that the key bushing which is underneath the key and that sits on these key pins right here. This one back here is the sharp key and these ones up front are the white keys. This bushing right here could be tight because that is felt which sometimes swells. It may need to be replaced or eased. They have a video that shows replacing the front rail key bushings. So sometimes that needs replaced. Or it could be that the balance rail felt is too tight. So there is also felt in this hole and that sits on these pins here which are the balance rail pins. So if either of those two felts are too tight you will push it down and because it is too tight the key will not want to come back up. So you may need to replace that or just ease. There are some tools available to iron the felt to make it a little bit looser on the pin.
One of the other possibilities could be this front rail pin or the balance rail pin are corroded. As I tool the keys off of this I could feel that they are not nice and smooth. They are rough because they have corrosion on them a little bit. If they are really badly corroded you will have to replace the pins. In most cases you can just use some metal polish and polish those up so that they are nice and smooth so the key can move freely up and down on the pin. Okay the same with the balance rail pins. These are pretty smooth so those probably don't need polished. But these front rail pins have caused some sticky keys on this piano and that seems what the problem is with this particular piano.
The other thing is the front rail pins in most cases are oval shaped. So the dimension side to side is not as wide as the dimension front to back. Sometimes if a key is too loose if it wobbles side to side then some technicians will take and turn that pin just a little bit so that it tightens it up and that over time can actually cause the key to be too tight. So you want to make sure that it's not turned so that it makes the key too tight on the pin. Or the pin could be bent. If it's bent then it's not going to slide freely up and down on it.
