How to regulate piano action back checks

Regulating the piano action back checks is an essential part of piano maintenance to ensure that the hammers return to their resting position properly and prevent double striking. Back checks are small, felt-covered wooden components located near the back of each hammer in the piano action. They engage with the hammer shanks when the hammer is lifted and then release the hammer when it falls back after striking the strings. Here’s a step-by-step guide on how to regulate piano action back checks:

Note: Piano regulation requires precision and expertise. If you are not familiar with piano mechanics or lack experience in piano servicing, it’s best to seek the help of a qualified piano technician.

Tools Needed:

1. Regulation screwdriver
2. Key easing pliers
3. Needlenose pliers
4. Hammer voicing tool (optional)

Steps:

1. Prepare the Piano:
   • Ensure the piano is on a level surface and the keyboard is clean.
   • Remove the piano’s front and fallboard to access the action.
2. Inspect the Back Checks:
   • Examine the back checks for any visible wear, damage, or misalignment. Damaged or worn back checks may need replacement.
3. Check for Proper Timing:
   • Play each key and observe the hammers’ motion. The back checks should engage with the hammer shanks just before the hammers reach the strings. If the hammers contact the strings before the back checks engage, there may be an issue with the regulation.
4. Adjust Back Check Height:
   • If the back checks engage too early or too late, use a regulation screwdriver to adjust the height of the back checks.
   • Turn the regulation screw clockwise to raise the back check height, and counterclockwise to lower it.
   • Make incremental adjustments and test the keys after each change.
5. Check Back Check Release:
   • After adjusting the back check height, play each key to ensure that the hammers release cleanly after striking the strings.
   • If a back check releases too slowly, it may cause sluggish key return. Adjust the height or check for any obstructions that hinder the back check’s movement.
6. Check for Double Striking:
   • Test each key quickly and lightly to check for any instances of double striking.
   • If you notice double striking, the back checks may be engaging too early or too late. Make further adjustments as necessary.
7. Voicing (Optional):
   • If you encounter hammers that produce uneven sound or have excessive noise, consider voicing the hammers using a hammer voicing tool. This process involves shaping the hammers’ felts to achieve a more balanced and consistent tone.
8. Final Testing:
   • Once all adjustments are made, play through the entire keyboard to ensure smooth, even key return and consistent sound production.

Note: If you are not familiar with piano regulation, it is advisable to seek the help of a professional piano technician. Piano regulation requires skill and experience to achieve optimal results without causing any damage to the piano’s delicate components.

In conclusion, regulating piano action back checks is crucial for maintaining the proper functioning of the piano’s hammers and preventing double striking. By following these steps and making precise adjustments, you can improve the piano’s touch and responsiveness, ensuring an enjoyable and satisfying playing experience. Remember that piano regulation is a specialized skill, and professional piano technicians can offer expert service to optimize your piano’s performance.