hammer return springs

[Lance Lafargue]

Keith,
I wrote this before I noticed your latest post.  See we're in past tense
now.
I have seen basically two types of factory installation on these.  
I remove the rail felt.
Measure the spring tension and the original touchweight.
Note the angle that the springs are at when at rest out of the action. 
This tells you something about their tension too.  Note length of
originals.
Clamp the rail to the bench with springs hanging over edge of bench.
Remove the old ones with a knife, awl, or screwdriver.
Run the new springs (about 8 or so) into the holes.
I then use a bamboo skewer (sand if too fat) run through the coils to keep
them aligned. Very important!
Pull the tail tight into it's slot. (CAREFUL TO END UP AT THE SAME ORIGINAL
ANGLE/GET APPROX. SAME TENSION)
The tail then needs to be tapped down (usually) into a slot that holds
them.
You can sometimes see a series of indentations where they were
crimped/pushed into the wood.  I duplicate that by tapping them in
(starting near the coil and working toward end of the tail) with a small
hammer and small slot screwdriver.
Then(as was sometimes done in the factory) I apply a drop of white glue to
the wire embedded in the wood to help hold it there.  
Then slip a few more into the holes, run the skewer down to hold them and
work your way across.  The glue dries as you work and you can then install
new springrail cloth or reinstall the original (if piano is pretty new) if
you cut it off with very sharp razor. (depends)
You then check tension/touchweight and bend to adjust.  
If spring does not fit perfectly in hammer butt groove,
dowel/redrill/relocate rail as needed.
Note: If the original ones were breaking at the coils and there is a piece
of cloth running along that facet of the rail (coil against felt), it is
probably true that the cloth attracted and held moisture longer, causing
the corrosion.  You sometimes see string breakage at stinging cloth before
other areas of the string because of this.  I have also heard that it is a
chemical oxidation that occurs(something in the felt).  You may want to
remove that if that's the case.  We get lots of that here in the south.  An
Okie can do this if a Cajun can! Best of luck!  Hope this helps some.  
Lance Lafargue, RPT
New Orleans Chapter
Covington, LA.
lafargue@iamerica.net

----------
> From: Keith McGavern <kam544@ionet.net>
> To: pianotech@ptg.org
> Subject: Re: hammer return springs
> Date: Wednesday, February 04, 1998 8:48 PM
> 
> Dear List,
> 
> I am preparing to replace hammer return springs on a K & C compact
action.
> Do you have any
> tricks or special tools in removing the old spring tails and inserting
the
> new ones other than ordering a new rail with springs already attached?
> 
> Keith A. McGavern
> kam544@ionet.net
> Registered Piano Technician
> Oklahoma Chapter 731
> Piano Technicians Guild
> USA
> 
>