[pianotech] adding weights

[Allen Fisher]

I would put the split shots the other way around so with a hard blow they would be less likely to loosen. The abrupt stop would be towards the closed side of the split shot.

From: deanmay at pianorebuilders.com
To: pianotech at ptg.org
Date: Fri, 24 Feb 2012 19:10:50 -0500
Subject: [pianotech] adding weights

























Subject was 30 year old Wurly console. Complaint was intermittent
sluggish keys. 

 

This was a multiple problem child. The presenting problem
was jacks not resetting. It had the nasty felt for the knuckles and backchecks
which contributed to excess friction on the jack. Then downweight was in the
low 40 gr range and upweight was less than 20. I find that that kind of low
upweight causes problems. It just isn’t enough to get things reset. 

 

I changed out knuckles and backchecks to Ecsaine to improve
friction. Then I added about a 10 gram weight into the back of the key and
about a 4 gram fishing line weight to the bridle strap wire. I also reduced
hammer spring tension slightly and damper spring tension until I was measuring
around 25g at damper head. Reducing these spring tensions helped keep
downweight from going up too much by adding the key/wippen weights. The results
were down weights around 50g and upweights in the mid to upper 20g. 

 



 

I added a drop of thick CA after crimping the weight just
for a little insurance. 

 

The improvement was huge. A very responsive action. This is
the first one that I’ve done adding the keyweights and wippen weights.

 

Dean

Dean W
May                       
(812) 235-5272 voice and text

PianoRebuilders.com          
(888) DEAN-MAY         

Terre Haute IN 47802          
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