S & S capo/Case hardening

[Bdshull@aol.com]

Fred,

Some ramblings about re-hardening the "V" bar.  I also noted Horace's comments
about case hardening the capo.  In the late 80's I decided to experiment with
a Steinway "V" (49" vertical) which had been beaten to death at the university
(by this time it was my piano).  I found a local welder and explained what I
wanted to do.  He used a TIG welder and reflowed the outer surface (less than
1mm) of the "v" bar, then lightly ground it smooth (it actually looked quite
good after the reflowing;  little grinding was necessary).  I did not instruct
him to make any changes to the original contour.  I was very happy with the
results.

I have discussed re-hardening the capo with various individuals.  Many were
with manufacturers reps or taught courses in the PTG.  There seemed to be a
lack of interest, and some ridiculed the need for rehardening the v bar.
However, at the time ('87 or so) Bill Garlick said that Steinway had begun the
practice of hardening the capo on their grands, and he felt it was essential
and was an improvement.

I attended a class at the 1999 California State Convention taught by Paul
Revenko Jones - a very interesting discussion of string termination.  Paul had
no experience with rehardening and was not able to shed light on the idea,
except to say that a plate is typically harder at the surface and that we
should be careful about reshaping the capo too exuberantly, to avoid losing
this harder surface.  

I believe that many heavily used performance pianos have damaged "V" bars and
would benefit from re-hardening with a TIG welder.  The TIG welder quickly
reflows the outer surface of the plate at the "V" bar without affecting the
subsurface, so is the ideal welding technique.  However, the grand plate must
be removed and may have to be carted to the welder.  Of course, the "V" bar is
a very important spatial point which must be kept - relocation of that point
would be a very bad idea. 

The front termination is a series of compromises, the right combination of
which may produce good tone - sometimes interesting, ugly from up close, but
beautiful and powerful tone.   The danger is to err too far one way or the
other with these compromises.

I believe that many of the problems we have with zinging and buzzing are the
result of the need for treble restringing - but the harder capo surface may
contribute to the need for replacement of strings;  this we cannot avoid.   Ed
McMorrow's ideas about a very narrow "V" bar made sense;  the problem is that
the softer, more narrow surface may not hold up well.  However, a broad, round
"V" bar may have too large a curve for a clean termination (as Paul Revenko
Jones explained, it damps more partials).  The harder surface might result in
more breakage, but the softer surface might deteriorate quickly.  Although I
am not a metallurgist, it seems to me that the harder "V" bar seems to be the
way to go.  Frequent restringing (5 to 20 years for a performance piano) of
the treble is part of that formula - something usually done anyway with the
performance piano.  

How desirable a softer or harder surface is, and how this relates to
termination and the production of tone, is partly a decision that might be
made first;  if you must have a softer "V" bar for your desired, then you
better not TIG weld.  But I don't have any solutions to a deteriorated "V"
bar.

I service an old "C" which has a cast steel plate (according to Steinway's
cast description in the plate).  I haven't had opportunity to drill locating
holes in the plate yet, but am curious about it.  Maybe someone on the list
can tell us about this plate.

Sincerely,

Bill Shull
U of Redlands, La Sierra U