Vertical hammer return spring slings, replacement of

[reggaepass@aol.com]

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Hi Tom,
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Thanks for the reference.  Excellent instructions.
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Alan=20
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-----Original Message-----
From: TOM DRISCOLL <tomtuner@verizon.net>
To: Pianotech List <pianotech@ptg.org>
Sent: Sat, 18 Feb 2006 11:33:49 -0500
Subject: Re: Vertical hammer return spring slings, replacement of


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Hi All,
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This Monday I will replace all of the hammer return spring slings on an olde=
r Yamaha U3.  Yamaha graciously provided the cord material.  Someone advised=
 removing all of the dampers and leaving the hammers on for the operation. =20=
However, looks to me like it would be rather tricky to get the glue and the=20=
right length of cord in the right place in the hammer flange slots with the=20=
hammers still on the rail.  My current plan is to leave the dampers, but rem=
ove all of the hammers so they may be handled individually.
=20
Anybody out there worked through this to their satisfaction?  Got a solvent=20=
that works better than alcohol for loosening up the old glue?  For installin=
g the new cords, have you used CA, hide glue, what-have-you? =20
=20
Any and all input is welcome, all the more so if it is before Monday morning=
.
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Have a good weekend,
=20
Alan Eder, RPT
   =20
Alan,
    This description from our friend Jon Page in=20
    much more detail than my post from the archives of some years back.
    Jon has chosen to omitt the use of acetone as a glue solvent in his step=
 9 but I find the acetone to virtually allow you to wipe the old cords from=20=
the slots  and have seen no deleterious effects on the flange bushings. JMHO=
.
    Tom Driscoll
   =20
   =20
Yamaha Hammer Spring Cord Repair=20

Problem:=20
  Hammer return spring cords have become fragile and are breaking.=20

Symptoms:=20
  Cords have turned a brownish color.=20
  Random breakage is occuring.=20
  Touchweight is affected on some notes where the spring is contacting the d=
amper lever.=20
  Hammer sometimes falls audibly into strings on slow release before being p=
ulled back by bridle tape.=20

Solutions:=20
  Replace hammer flanges=20
  Replace cords=20

Condition of action:=20
  If condition of the hammers, pinning, and travelling/mating to strings is=20=
all good, replace cords.=20
  If pinning is poor then flange replacement may be a better option.=20
  Beware of earlier type action without butt plates - the following method w=
ould not work in this case.

Cord Replacement Procedure:=20
  1.    Place action in cradle; remove hammer rest rail and treble bracket.=20
  2.    Reverse action so that hammers and dampers are facing you.=20
  3.    Loosen hammer butt plate screws.=20
  4.    Remove hammer assemblies from flanges and let hang from bridle wires=
; keep them in order to avoid tangling.=20
  5.    Straighten any bent return springs.=20
  6.    Tighten all wippen flange screws.=20
  7.    Tilt action toward you 90=B0 so that the hammer flange cord slots fa=
ce upward.=20
  8.    Tighten remaining flange screws.
  9.    Using specially adapted shimming chisel or other suitable tool, clea=
n slots (no solvent) and vacuum up debris.=20
10.    Wrap 90+ turns on dowel with new cord and cut turns with a razor.=20
11.    Glue one end of each piece to one slot on each flange.=20
12.    Return to first flange and glue the other ends to remaining slots; ch=
eck with gauge.=20
13.    Lubricate damper spring slots.=20
14.    Replace hammers; tighten butt plate screws; hook springs under flange=
 cords as you go.=20
15.    Replace hammer rest rail bracket and reinstall rest rail.=20
16.    Final check: jack springs engaged with jacks, spring cords in crook o=
f hammer return springs, bridal tapes not twisted.=20


Tools and Materials:=20
  __flange, thin-bladed, and Phillips screwdrivers=20
  __spray lube and spring hook (for damper springs)=20
  __shimming chisel modified to clean flange slots, or other suitable tool
  __glue applicator (syringe) filled with Tightbond & damp rag=20
  __action cradle=20
  __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 car=
dboard
  __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=20=
check loop size)=20
  __razor=20
  __forceps=20

Many different types of cord will work. White braided Dacron looks the best=20=
and will last forever. Joe Goss suggests Spider Wire which I've bought but h=
aven'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 w=
ell to Tightbond. Probably the easiest (and possibly cheapest) is to order t=
he 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.=20

This method is taken from Tom Driscoll who posted it to the list in May, 200=
2 (Yamaha Upright Hammer Flanges).=20
   =20
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