S & S capo/Case hardening

[Bdshull@AOL.COM]

Ron  and list:

Although I do not speak with the same eloquence as Ron, nor the same knowledge
of metal hardnesses, I think that the purpose of the front duplex has been
missed here.  We don't get zings from the agraffe section for a simple reason:
The agraffe section is designed to exclude them.  We get zings from the duplex
section for a simple reason: The duplex section was designed to "include"
them.

Ron, your solutions to the problem (increased angle and shortened segment of
the duplex) show that those solutions are effective in getting rid of zinging,
but not necessarily an argument against "V" bar hardening.  Redesigning may or
may not move towards the intent of the designer, but simply restringing that
section with a light capo surface preparation of the capo is often as adequate
a solution.

The problem is that the capo is designed for an incomplete termination of the
string.  Until significant loss of power occurs in this section the capo is
probably in good shape.  When loss of power and tonal aberrations are
percieved from a distance, it may be time to restring and lightly resurface
the capo.  In certain circumstances rehardening the "V" bar may be needed:
heavy use with many restringings/hammer replacements, or where the plate
surface was poor to begin with, either from poor manufacturing or from
exhuberant filing/grinding.

TIG welding is not particularly expensive, nor is it particularly
transmogrific.  It is inconvenient and increases our risk when we cart the
plate to the welder.  But rehardening, when needed, provides an effective  way
for the rebuilder to maintain the duplex scaling intent of the manufacturer.
Other approaches with this same intent have been made, including the insertion
of a rod into a groove made into the capo.  Rehardening seems to be the best
way to keep the duplex as original as possible. 

Ron, I am a comparatively recent caut and pianotech list participant, and I
continue to appreciate your way with words....Even if I might not alway agree
-

Bill Shull
U of Redlands, La Sierra U