Instructions for Piano Key Bushing Cauls
Dec 11, 2023
Below you will find some uses for Piano Key Bushing Cauls and other information about the product.
About the Product
Piano Key Bushing Cauls are a type of clamp that goes in and stays in while the glue is drying to hold the felt in place. You will know that your key bushings need replaced it the piano keys are wobbly or loose on the keypin. Once the glue is set, you can remove the caul. Choose from a set of 5 cauls or a set of 45 cauls. 23/64" (9.25mm") wide (front to back). Tolerance to within .001".
Below are instructions on how to use the product.
You will need to start by removing the felt that needs replaced. It could be the front rail pins, balance rail pins, or both. If the bushings are loose, they need replaced. A good sign of this is a wobbly key.
Using a Hypo Oiler, put two drops of a mixture of water and alcohol on each side of the bushing needing replaced.
Use a Key Bushing Tip Burning Blade on a soldering iron, preferably with a soldering iron station so that the iron does not become too hot (this could burn the felts and will not lead to good results). To test that the iron is at the right heat setting, simply place a drop of your water and alcohol mixture onto it and make sure it boils. Insert the tip into the soaked bushing and leave it in for several seconds, moving it around in the hole. If it doesn’t work on the first try, add some more of the mixture and try again. It could take several tries.
Let the bushing hole completely dry before putting the new felt in.
To see a more detailed demonstration of this process, watch this video:
Install New Bushing Cloth with Bushmaster
First, measure your keypins. The size of keypin will determine what size Key Busing Caul you need to use in the installation process.
The next step is to determine the thickness of key bushing cloth you will need. Make sure it is not too thick or thin, as this can cause the bushing to be too tight or loose on the pin. The best way to determine this is to test the cloth by placing it over the hole and pushing the correct size caul into it. It should have some resistance but not be very difficult to get in.
Once you have determined your sizes, put some PVC-E Glue on a toothpick or small brush. Rub the glue into the hole, going only about 3/16" into the hole on either side along with a bit of the surface around the hole on either side. Use enough glue that it covers the surface, but not so much that it will ooze out when you push the cloth and felt in.
Hold the felt across the hole. Use a Bushmaster to cut the necessary slit in the center of the cloth over the hole. Continuing to hold the cloth in place, take you caul and push it into the hole. Ensure that it is in the hole firmly by pushing on it. This will clamp the cloth in place until it is dry. Cut any excess cloth off with a utility knife. The cloth should stop at the edge of the caul. Let set for 30 or (preferably) more minutes.
Install New Bushing Cloth without Bushmaster
First, measure your keypins. The size of keypin will determine what size Key Busing Caul you need to use in the installation process.
The next step is to determine the thickness of key bushing cloth you will need. Make sure it is not too thick or thin, as this can cause the bushing to be too tight or loose on the pin. The best way to determine this is to test the cloth by placing it over the hole and pushing the correct size caul into it. It should have some resistance but not be very difficult to get in.
Once you have determined your sizes, put some PVC-E Glue on a toothpick or small brush. Rub the glue into the hole, going only about 3/16" into the hole on either side along with a bit of the surface around the hole on either side. Use enough glue that it covers the surface, but not so much that it will ooze out when you push the cloth and felt in.
Take both ends of your key bushing cloth and put them into the keypin hole. Try to ensure that each end goes the right amount of distance into the hole. Continuing to hold the cloth in place, take you caul and push it into the hole. Ensure that it is in the hole firmly by pushing on it. This will clamp the cloth in place until it is dry. Cut any excess cloth off with a utility knife. The cloth should stop at the edge of the caul. Let set for 30 or (preferably) more minutes.
To see a more detailed demonstration of these processes, watch this video:
