How a Vertical Piano Action Works

How a Vertical Piano Action Works (Piano Tuning and Repair)

Welcome to our Series on Piano Tuning and Repair.

There are a lot of things that happen in a piano action from the time the key is pressed until the time the string plays a note. The video above goes through the different things that happen in a vertical piano action when a note is played.

If you want to see more of our Piano Tuning and Repair Seriesclick here to access the entire playlist.

Video Transcript:


Thanks for joining us here today for another video from Howard Piano Industries. Today we're going to be walking through the process of looking to see how a vertical piano action actually works. Here in front of you you've got a vertical piano action model and this is going to show you all the different parts and how they work together to create what happens when you press down the key and the hammer strikes the string and it makes the sound of a note. We're going to show you how all the different parts work so that you can understand and look and see what actually happens in a piano when you play a note.

Piano Keys

We're going to start up here and we've had a different video that shows you all the different parts and names and everything so we're going to go into a little more detail of how things work today. Now what happens, obviously this you might recognize, is the key, so you're going to press that down and I'm going to just go do it quickly so you can see that all the different parts that move in the action and ideally what happens is the hammer strikes the string, the string will vibrate, and that's what makes the sound, so that string is vibrating, that's what makes the sound that you hear when a piano key is played. Now what happens is the key is pressed down and as you can see, the front of the key, which this would be the front of the key over here, when that's pressed down the back of the key is going up.It balances on this this part right here, what's called the balance rail.

Capstan & Whippen

As the front of the key goes down and the back of the key goes up this piece right here, which is called the capstan pushes up on this part right here, which is called the whippen. That pushes the whippen up, I can even push that whippen up without moving the key and that'll still do the same thing. This whole lever right here, which is called the key, pushes down on the front and pushes up on the back so that pushes the whippen and what happens is this piece right here, which is called the jack, you can see pushes up on this part right here, which is called the hammer butt and it pushes the hammer butt forward which makes the hammer go forward.

Jack & Hammer Butt

We'll get to these other pieces in a minute here but what happens is that hammer goes forward, it's going to, and if I do it really slowly, you can see hopefully in the video that it gets almost to the string but doesn't reach it completely. If I hit it hard then the strings, then the hammer is going to go all the way and hit the string but if I do it really slowly the hammer actually comes very close to the string but then releases as it gets close. Now the reason it releases and it doesn't go all the way to the string is because the jack, this piece right here, this is called the toe of the jack and that hits what's called right here, the regulating button and as the toe of the jack hits the regulating button, if you watch it really slowly you can see the toe pushes against that regulating button which makes the top of the jack come forward, see that, and as that Jack comes forward that releases the hammer butt so that it stops moving forward from the movement of the jack and the reason for that is if the jack pushed the hammer all the way up to the point of the hammer hitting the string then the hammer couldn't be released and the hammer would just go up against the string and it wouldn't be able to vibrate because the hammer would be pushing up against the string which if something is holding on to the string it's not going to be able to vibrate so what it does, is it gets it close enough so that with the power of the jack, or the movement of the key, so that it can get almost to the key and then release so that the string can vibrate so that the hammer just hits it very quickly and falls back and the string can vibrate. Now what happens, when that hammer comes back it's not allowed to fall back all the way to its resting position, which is of course back here on this hammer rail, but when you play it, it's caught by this piece right here, which is called the back check.

Back Check

The back check catches this piece called the catcher and it holds the hammer so that it doesn't fall all the way back and the reason it does that is it aids in when you're repeating the note, so it would be much less efficient if the hammer had to fall all the way back each time before you could repeat the note. That's the back check catching the catcher. The other part of it is it's got this piece right here, called the damper.

Action Damper

You can see there's felt on this resting against the string when the hammer is at rest or the key is at rest and what happens is, as the hammer goes forward you can watch this piece right here, the damper lifts off the string.

Action Spoon

Now, the damper is there so that the string won't vibrate when you don't want it to so what happens is when the key is down that damper is lifted off and the way that it's lifted off is back here by this piece, called the spoon, the spoon pushes against the damper lever and it's this silver piece right here, that's attached to the whippen and that pushes against the damper and raises the damper lever up off the string. Let me show you show you slowly again. As you can see as they start to slowly push down the key, that raises the damper lever, now you can adjust that spoon so that the damper can start to raise the damper earlier or later depending on what you want to do. That's part of the adjustment process, but that's what the damper is. So basically, when you push down the key it pushes up on the jack which pushes up on the hammer butt, the hammer goes forward until the jack toe hits the regulating button which releases the hammer so that it can fall back and be caught by the back check, all the while the damper felt, the damper is being raised up off the string. Now, if you notice, when you of course, when you let go of the key, and now you might notice when you play a key that the note keeps ringing until you let go of the key and the reason that the string or the string stops vibrating or the note starts/stops ringing is that the damper felt or the damper head is going to go back down and go up against the string which is going to stop the sound. So those are the basic functions of an upright piano action and how it works. Hopefully that helps you to understand it better.