Dec 3, 2013



Discussion group

Broken cord will give a metallic noise and loose touch, see here

Below is quoted from (I believe the original is provided by Wayne Walker)

Cord Replacement Procedure:
1. Place action in cradle; remove hammer rest rail and treble bracket.
2. Reverse action so that hammers and dampers are facing you.
3. Loosen hammer butt plate screws.
4. Remove hammer assemblies from flanges and let hang from bridle wires; keep them in order to avoid tangling.
5. Straighten any bent return springs.
6. Tighten all wippen flange screws.
7. Tilt action toward you 90° so that the hammer flange cord slots face upward.
8. Tighten remaining flange screws.
9. Using specially adapted shimming chisel or other suitable tool, clean slots (no solvent) and vacuum up debris.
10. Wrap 90+ turns on dowel with new cord and cut turns with a razor.
11. Glue one end of each piece to one slot on each flange.
12. Return to first flange and glue the other ends to remaining slots; check with gauge.
13. Lubricate damper spring slots.
14. Replace hammers; tighten butt plate screws; hook springs under flange cords as you go.
15. Replace hammer rest rail bracket and reinstall rest rail.
16. Final check: jack springs engaged with jacks, spring cords in crook of hammer return springs, bridal tapes not twisted.

Tools and Materials:
__flange, thin-bladed, and Phillips screwdrivers
__spray lube and spring hook (for damper springs)
__shimming chisel modified to clean flange slots, or other suitable tool
__glue applicator (syringe) filled with Tightbond & damp rag
__action cradle
__replacement cord, e.g., braided Dacron of suitable diameter (kite string, parachute cord) or silk cord (Pianotek)
__9/16" dowel [turned down from 5/8" dowel] or suitable width piece of cardboard
__blunted scriber (or use small screwdriver, to help place cords in slots)
__gauge (dowel, sized to fit intact flange cord, with end rounded off, to check loop size)

Many different types of cord will work. White braided Dacron looks the best and will last forever. Joe Goss suggests Spider Wire which I've bought but haven't tried yet. It's a similar color to the stuff you're replacing so that tends to go against using it. I used to use squidding line but the kind you'll likely find in fishing supply places is waterproofed and wouldn't take well to Tightbond. Probably the easiest (and possibly cheapest) is to order the silk action cord from Pianotek ($3.95 for a 30-yard roll).

Cleaning out the slots is not critical and you could even give the flanges a quickie scrub and vacuum treatment and commence with step 10.

This method is taken from Tom Driscoll who posted it to the list in May, 2002 (Yamaha Upright Hammer Flanges).

Wayne Walker
Walker's Piano Service

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