[pianotech] sostenuto mount retrofit

[Ron Nossaman]

Gene Nelson wrote:
> Did you modify those bolts or buy them that way?
> Gene

They're regular old 5/16" carriage bolts with the head turned 
down. The square on the shank provides the flats for in and 
out adjustment with a small open end wrench. I drill and tap 
the end for the same 10-24 bolts I use for damper tray capstans.
Ron N