Piano Key Bushing Replacement

As pianos get played, the bushings in the front and center of the key will get worn, which results in wobbly keys.  When this happens the key bushings need to be replaced.  The videos below show the process for replacing the bushings as well as the parts and tools needed.  Here is a list of tools that are needed along with links to the items in our store:


Parts and Supplies Needed:

- Key Bushing Cloth
- Key Bushing Cloth - Extra Thin
- Piano Key Bushing Cloth Sample Kit
- Key Bushing Tip Burning Blade
- Soldering Iron
- Soldering Iron Station
- Hypo Oiler
- Key Bushing Cauls
- PVC-E Glue
- Bushmaster 

This video is part 2 of the key bushing process. The first video that we have which you may have seen was the process of removing the old key bushings from the key in order to be able to put the new bushings in the key bushings. They go into a hole in the bottom of the key. This would be for the front rail pin that sits over in the key bed. The other one here, is in the middle of the key and that's for the balance rail pin. Both holes are lined with felt. This one, we've taken the felt out in preparation for putting the new felt in. The first step that you're going to want to do is, you're going to need to measure your key pins to determine what size key pins you have because that'll determine what size caul or clamp you're going to use. For the key bushing felt the most common is .146, but of course there are other sizes as well, so you'll want to make sure you find out the correct size so that you can properly rebush the hole. Now this is a key bushing caul. A pretty important part of making sure you get a nice finished product when you're rebushing keys. This is a type of clamp that goes in and stays in while the glue is drying, and for the felt until the glue sets. This particular one is made for key pins that are .146. So the key pins that I have are that size, so that's the size caul I'm going to use. The next step is to determine what size of cloth that you need because that's going to determine the right tightness on the pin. You don't want it to be too tight so that it binds, but you don't want to be too loose so that the key wobbles either, because most likely you're replacing the felt because it was too loose in the first place, so the way to get a good fit is to test it and I've tried some different sizes. I already know that this particular cloth that's .039 thick and it seems to be a good fit. Now the right fit is if you set it over the hole and push your caul in. The right size caul, it should go in. It should feel some resistance but not be too tight. So once you get it in there, and there you go, to push the caul in, again, there should be some resistance, but you don't want to have to really shove it in there because that means it's going to be too tight and you're going to have binding. So I'm getting a good fit. It's kind of crucial. So once you've done that and determined the right size caul and the right size cloth and we're ready to glue it in. The best glue for gluing in key bushings is the PVC-E glue which we have available. What you're going to do is, you can use a small brush. I tend to use a toothpick works pretty good. Everybody's got their own preference for that and what we're going to do is, we're going to put enough glue in to go down about 3/16 of an inch into the hole, and you're going to do this area here and then again about 3/16 inch down into the hole, so a little bit, so what I'll do is toothpick here You don't want to use too much glue, otherwise it makes a mess, but you want to get enough so that it covers the surface. Spread it out real good across the surface of where you want, where the felts going to end up being once you have the glue in place. The tool that I use is called a Bushmaster, which is the most efficient and easiest tool to use for key bushing getting the right depth and cutting the felt and so forth. So what I do is put the felt, I'm going to hold it on the edge here drape the felt across the hole, push, and then I'm going to hold both sides here so that the felt stays in place. So I'm going to just put that in and then I'm going to, what that does is, that has a blade that comes out and it actually cuts the felt inside the hole so that you've got the separation and then what you do is you put the caul in place like this and give it a nice firm push on it so that it's in there real nice and snug and then once you've done that we'll take a sharp knife, I just use a utility knife here, and cut it off at the edges of the caul, and there we've got our caul holding the key bushings and with the Bushmaster tool it sets the the depth of the felt at the right amount and cuts the felt nice and clean inside the hole and that's the process using the Bushmaster. Now you don't if you don't have the Bushmaster, or don't necessarily want to invest in that particular tool you can do it without using that tool. here I've got another key. Now this one, it's from the same piano, but actually the 0.043 inch cloth was a better fit for this. Now what you can do here is tape, and you can glue it in, it's a little more difficult though. What you would do is, you would spread your glue just like we did with the other key, then you would take both ends of the key bushing cloth and you would try to get it in about the right distance. Again, it's, and of course, I don't have the glue on yet, but you would put the glue on and then insert your cloth into the hole, there's such, kind of hold it back like that then insert your caul like that, and then cut off here, cut off your cloth and then let the caul set, and of course, you want to, once you've got the caul, and you want to let that set for quite some time until the glue dries, so make sure that you let that set for at least, say 30 minutes or longer to make sure the glue is dry before you pull the caul out. The longer you can let it set the better, but it's best to let it set 30 minutes at least maybe an hour or longer, until that glue is completely dry. So that's the process of putting in new key bushings in the piano keys.

Products used in these videos: