Grand Trapwork Servicing!

Why Trapwork Service Matters in a Piano Tuning Course

In any professional piano tuning course, technicians quickly learn that tuning alone is not enough. Pedal performance on a grand piano directly affects control, comfort, and musical expression. That is why grand trapwork servicing is an essential skill taught in advanced piano tuning and repair courses and real-world piano technician training.

When trapwork is serviced correctly, the pedals feel lighter, operate silently, and respond consistently across the full range of motion.

What Proper Trapwork Service Improves

• Correct pedal weight and throw on all three pedals

• Elimination of squeaks, clicks, and creaks at the source

• Reduced friction and lost motion for better control

• A clean, professional finish that respects the original build

Common Trapwork Problems Covered in a Piano Tuning Course

These are the real issues technicians learn to diagnose and repair in a comprehensive piano tuning course:

• Pedal stiffness or foot fatigue, especially on damper or una corda

• Una corda not engaging or failing to shift the action

• Audible squeaks, clicks, or creaks from springs and contact points

• Short sustain throw that advanced players immediately notice

• Problems after a move, such as missing dowels, springs, or misalignment

Tools and Supplies Used in Piano Technician Training

Cleaning and Prep

• Method-type cleaner and lint-free rags

• Brasso or equivalent metal polish (Fritz or Soltz) for pins

• Blue painter’s tape for labeling and temporary clamping

• Field journal and pencil for order, measurements, and notes

Adhesives and Contact Surfaces

• Aleene’s Original Tacky Glue (standard version, not clear)

• White Wurzen front-rail felt sheets, sliced into thin custom pads

• Thick or belly felt for swing-arm stops

• Leather stock such as boot or saddle scraps

• Leather and felt hole-punch set and razor blades

Lubrication

• Super Lube clear synthetic or similar PTFE grease

• Teflon powder for keyframe-to-keybed glide

Hardware and Spares

• Assorted coil and leaf springs

• Wooden dowel stock and small metal pin stock

• Small saw and drill for dowel fabrication

• White balance-rail punchings for spacing

Step-by-Step Grand Trapwork Workflow

As taught in our piano tuning and repair courses

1. Remove the action and organize the work area.
   Work one zone at a time: damper, sostenuto or bass-lift, and una corda.
   Label every part.
2. Clean and inspect all components.
   Degrease, wipe, and polish pins.
   Inspect wood and plastic parts for cracks or wear.
3. Renew contact surfaces.
   Replace worn leather and felt.
   For curved parts, glue and tape-strap while curing for 15–20 minutes.
4. Make custom felt parts.
   Slice thin Wurzen strips and avoid soft craft felts that compress too easily.
5. Lubricate carefully.
   Apply a thin film only to pins, guides, and rub points.
   Never over-lubricate.
6. Quiet noisy springs.
   Weave a thin felt strip through the coil.
   If stiffness remains, commonly on some Steinways, remove the lower trap spring while leaving the tray spring.
7. Set up the una corda.
   Reduce keyframe-to-keybed friction with Teflon powder.
   Verify leaf-spring tension.
   Remove excess lost motion.
   Repair worn keyframe contact areas with a hardwood graft if needed.
8. Adjust damper throw.
   If sustain feels short, trim the hard felt limiter block by one-quarter to one-half inch.
   Always get client approval before making this change.
9. Time the sostenuto or bass-lift system.
   Rebuild contact surfaces and confirm correct two-stage linkage timing.
10. Fabricate missing dowels.
    Cut, drill, pin, and install from below.
    Adjust rod height to achieve proper lost motion.
11. Reassemble and test.
    Torque hardware securely.
    Test quietly first, then at performance force.
    Confirm smooth return, even resistance, correct timing, and full pedal throw.

Trapwork Troubleshooting Quick Reference

• Dead pedal after a move
  Check for a missing spring or dowel and look for an empty recess.

• Clicking spring
  Weave thin felt through the coil and lubricate contact points.

• Squeaking leaf spring
  Replace worn leather and apply light lubrication.

• Heavy una corda
  Reduce keyframe-to-keybed friction first and adjust leaf tension last.

• Short sustain travel
  Trim the limiter felt and retest with the player.

Why This Matters for Piano Tuning Students

Trapwork servicing is often skipped in basic tuning instruction, yet it is a core skill taught in a complete piano tuning course. Mastering this work separates simple tuners from confident, full-service piano technicians and directly improves playability, reliability, and client satisfaction.