new underlever installation

[Mike Spalding]

I'm glad you asked, because I'm in the middle of my first underlever 
system replacement, and have similar questions.   I'm taking a horrific 
loss in terms of the time spent thinking about this as I do the work, 
but hope to only have to over-think on the first one.  So I want to 
learn about all the possible variants, even the ones that don't apply to 
this first job - sooner or later I bet I'll see them.

In addition to the Renner instructions, I've been referring to the 
Journal article by Tim Dixon RPT (August and September 2001).  His 
recommendation is to locate the pivot pin hole further forward in the 
tray so as to locate the tip of the sost. tab in the same place as the 
original.  Although this might incline the damper wires off of vertical, 
he doesn't consider this to be a problem.

Tim also recommends setting the horizontal (front-back) location of the 
new tray off of the top post center pin, rather than the tip of the 
underlever.  This was key to my job, this time, because the center pin 
to underlever tip distance on the originals was 3mm longer than on the 
replacements.  If I had put the underlever tips in the same location, 
that would have moved the sost. tabs 3mm closer to the action.

After y'all have chimed in on David's specific question, I'd like to 
hear about all the other dimensional discrepancies you've run into, and 
how to deal with them.

thanks

Mike

David wrote:

Frequently when installing new Renner underlevers I run into the problem
that the new sostenuto tabs extend farther out than the old ones.  Moving
the sostenuto rod in far enough to allow for proper regulation often results
in clearance problems between the backchecks and the sostenuto rod itself.
What is the best way to modify the original set up such that I don't create
other problems.  

David Love
davidlovepianos at comcast.net <https://www.moypiano.com/resources/#archives> 
www.davidlovepianos.com