Grand Piano Troubles!

Common Grand Piano Action Issues

Tools You’ll Need

• Universal Capstan Adjuster – Covers multiple capstan styles, including historic Steinway square types and modern round varieties.
  
• Tweezers – For finesse work
  
• Harp Spring Tool – A must for regulating repetition lever springs.
  
• Drop Screw Regulator – No real substitute for this when adjusting jack or drop screws.
  

Optional extras include a backcheck regulator, screwdrivers for action cavity access, and checkering files.

Common Grand Problems: No Aftertouch, Bobbling Hammers

At a customer's home, you may hear: “It just doesn’t feel right. It hasn’t been worked on in years.” What you find is often something like this:

• Bobbling hammers
  
• No aftertouch
  
• Action feels unresponsive
  

Step 1: Observe and Press Slowly

Start by pressing the key slowly. Ask:

• Does it reach let-off?
  
• How much force is required?
  
• Is there any escapement feel?
  

In our model, we noticed it barely reached let-off, and it required way too much pressure—an immediate red flag.

Step 2: Check Key Dip

In most pianos, the key dip drifts due to keybed settling, especially in the middle of the piano. If you’re not getting your 10mm of dip, escapement is compromised. Punching or repunching can correct this. In our training model, we increased dip and immediately noticed better response.

Step 3: Regulate Let-Off and Blow Distance

After setting key dip:

• Let-Off: Adjust it to around 1/16" from the string. Use your capstan adjuster.
  
• Blow Distance: Check with a blow distance gauge. A typical spec is 1-3/4" to 2".
  

*Blow distance is the easiest to adjust and often the most out of spec.

Step 4: Correct the Backcheck

Three backcheck issues to watch for:

1. Distance: Aim for ~5/8".
   
2. Angle: Misalignment can cause drag.
   
3. Tail Texture: If the hammer tail is too smooth, it won’t catch properly. Use a checkering file to roughen it slightly.
   

*Some techs sand the leather on backchecks, but that’s usually only necessary if it's corroded or uneven. In most cases, focus on the tail and alignment.

Step 5: Adjust Repetition Spring Tension

You want that hammer to rise smoothly— The spring tension should feel like a gentle squat—controlled and balanced.

Tips:

• Always preserve the spring’s original shape.
  
• Adjust by carefully pulling the spring out and bending it—not flattening it.
  
• If the action is sluggish, check for:
  
  • Rough knuckles
  • Dry spring homes
  • Tight repetition centers
    

Step 6: Fine-Tune Drop

With spring tension corrected, go back and recheck drop. Adjust using the drop screw so the hammer doesn't fall too deep post let-off.

Step 7: Wink the Jacks

“Winking the jacks” means ensuring the jack is just barely under the knuckle with no excessive play. If it’s out of alignment:

• Raise the repetition lever window slightly.
  
• Test by moving the jack and watching the hammer assembly’s response.
  

Failure here can lead to misfires—a note being played without sound due to poor jack positioning.

Step 8: Damper Timing

Check when the damper starts to lift:

• Ideal: Between 1/3 to 2/3 into the key stroke.
  
• Too early? The back of the key is pressing on the damper lever prematurely.
  
• Adjust via the damper spoon or underlever screw inside the action cavity.
  

*Advanced tip: Lightly lubricate the key-end felt to reduce bump feel.

Bonus: Raising the Hammer Line

*If you’re short on time or can’t adjust key dip, slightly raising the hammer line (via capstans) gives a bit more aftertouch. It’s a useful quick-fix, especially if the customer doesn’t want a full regulation.

Common Adjustment Priorities

Which adjustments give you the biggest bang for your buck?

1. Blow Distance – Quickest and most impactful.
   
2. Let-Off – Easy and clean.
   
3. Key Dip – Takes more time; worth it if you're doing a full regulation.
   

*Becoming a technician means being willing to fail, to learn, and to dig deep. It’s not always easy—but it’s so worth it. When a client calls to say, “You made my piano come alive,”—that’s when you know you’re making a difference.

So take the risk, keep asking questions, and don’t be afraid of the messy process. You’re not just fixing a piano—you’re elevating the art of piano craft.