Fw: Larudee's mystery - Was: Ditch the tuning pin bushings

[larudee@pacbell.net]

David Skolnik wrote:

> 1) I've seen no science or concurring testimonials, as yet, which might
> convince me that the greater surface area contact of pin to block is not an
> equal, or perhaps greater contributor to the loss of refinement in tuning
> than the reduced dimension of the coil portion

First of all, the reduced dimension of the coil portion is not a contributor to
loss of refinement in tuning.  Just the opposite, which may have been what you
intended to say, i.e. that the greater surface area in the lower area of the pin
offsets the gains at the coils.  Correct me if I'm wrong.

My response is that the friction depends on two things:  the surface area and the
tightness.  As with any pinning, we need to make the tightness optimal, which in
this case would be slightly less than with a smaller pin to achieve the same
friction.

> 2) How might such pins respond to high torque conditions (i.e 120 - 160
> inch pounds) with regard to torsion, flexing, failure, etc.? Neither on the
> previous thread (Ditch) nor on this one, thus far, have we discussed, in
> metallurgical terms, what really takes place in pin torsion and flex
> (flagpolling).  I know they have been written about in the Journal, but do
> not yet possess the search skills to locate such information Torsion
> (twist) would not seem to be an issue until we move into the higher torque
> measurements.  Does a highly torqued pin develop internal torsion?  How
> long does it take the pin to restore equilibrium (?) Would this dissipation
> of energy affect string tension?

That is the case with any pin, and depends upon its rigidity (elasticity).  The
elasticity is a bigger factor the narrower the pin and the greater the distance
between the point of string tension and the fulcrum of the pin (the top of the pin
block).  That is why more torsion will take place in pins in a closed pin block
design than in an open one.

Paul Larudee