Yamaha spring cord replacement

[David Ilvedson]

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I would only ask where do we get the dacron of appropriate size?
David I.
PS   Good description Tom!




Original message
From: Piannaman@aol.com
To: pianotech@ptg.org
Received: 9/21/2005 3:29:38 AM
Subject: Re: Yamaha spring cord replacement


In a message dated 9/21/2005 6:43:43 AM Pacific Standard Time, piano57@=
insightbb.com writes:
Hello folks who are more organized than I am,
 
Oh groan. I saved the instructions (on a disk) for replacing those pesk=
y little spring cords and now I can't find it.  Would someone please se=
nd them along to me  (You know, the instructions that include removing =
the hammer rail.).  Though I read them--a long time ago--I can't rememb=
er all the details (Guess I've been eating too many aluminum bushing ca=
uls), like how long the job is supposed to take.
 
Thanks,
 
Barbara Richmond, RPT
 
Barbara,
 
Here are instructions.  I got them from Tom Cole, RPT.  He can do it in=
 around 2 hours, give or take. I'm sure his shop area is far more effic=
iently organized than what I was using at the time.  The first time too=
k me around 4, second time was about 3 hours.  I see another one on the=
 horizon soon!
 
Dave Stahl
 
 
Problem:
Hammer return spring cords are breaking due to unknown cause
Symptoms:
Cords have become a brownish color
Random breakage is occuring
Touchweight is affected on some notes; hammer sometimes falls into stri=
ngs on slow release
Solutions:
Replace hammer flanges
Replace cords
Condition of action:
If condition of the hammers, pinning, and travelling/mating to strings =
all good, replace cords.
If pinning is poor then flange replacement may be a better option.
Cord Replacement Procedure:
1. Place action in action cradle
2. Remove hammer rest rail and treble bracket
3. Loosen hammer butt plate screws
4. Remove hammer assemblies from flanges and let hang from bridle wires=

5. Straighten any bent return springs
6. Tighten all hammer/damper/wippen flange screws
7. Tilt action 90=B0 so that the hammer flange cord slots face up
8. Using specially adapted shimming chisel, clean slots and vacuum up d=
ebris
9. Wrap 90+ turns on dowel with new cord and cut turns with razor
10. Glue one end of each piece to one slot on each flange
11. Return to the first flange and trim each cord to length
12. Glue other end to remaining slot; check with gauge
13. Replace hammers; tighten butt plate screws; hook springs under flan=
ge cords as you go
14. Replace hammer rest rail bracket and reinstall rest rail
15. Final check; jack springs engaged with jacks, spring cords in hook =
of hammer return springs, bridal tapes not twisted
Tools and Materials:
=AE flange screwdriver
=AE thin screwdriver
=AE Phillips screwdriver
=AE shimming chisel modified to clean flange slots
=AE glue applicator (syringe) filled with Tightbond
=AE end nippers with gauge
=AE action cradle
=AE replacement cord (braided Dacron of suitable diameter)
=AE 5/8" dowel [9/16"]
=AE blunted scriber
=AE gauge (dowel)
=AE razor
=AE forceps
=AE damp rag

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