Talkin' Torque

[Bill Ballard]

Hey Gang,
Guess what I did last Sat. I took a piece of pinblock scrap and made a
device for observing tuning pin torsion (you know, the twist which we
leave in a tuning pin if we're not careful). Drilled a hole for the
tuning pin, ran a band-saw kerf over to it, and set a lag bolt across
that kerf for adjustable torque on the tuning pin, installed a piece of
music wire leaving the bottom end of the pin which could be visually
checked against a piece of wire coming out of the becket. At rest, the
two wires were set parallel.

The results were dumbfounding (actually, it doesn't take much). Even at
200 "/# torque (the most I could get from this firstversion of the
torsion indicator), there was nary a 1 degree lag between the top and
bottom ends of the pin. and as soon as the bottom stopped moving, and I
stopped pushing on the top end, the two were in perfect alignment. So
where's this mythical "twist-in-the-pin" which haunts our dreams? It
probably has as much effect on the stability of the tuning as the test
blow, which (as calculated for the string path of C52 on a Steinway B)
barely musters 3.7 oz.(correct me if I'm wrong, Doug - you've got the
spreadsheet) of extra string tension in the face of the 20#
friction barrier presented by the capo bar. (BTW, this is part of the NH
Chapter's Jr. Science Project.)

Startled? Check it out for yourself.......

Bill Ballard RPT
NH Chapter

"We mustn't underestimate our power of teamwork." Bob Davis