Upright Damper Regulation

[Keith A. McGavern]

>I am in the final stages of regulating the action on a Vose & Sons
>upright that I have reconditioned (new felts, springs, etc.) and am
>stumped by a problem that has cropped in regulating the dampers, in
>particular the bass section.  This action has the usual two piece
>damper lift rod, splitting at C3. The bass dampers are regulated so
>that they lift evenly from the bass damper pedal, which of course
>operates from the bass or left side of the action.  However, when the
>full damper pedal (right) is operated, the bass dampers lift late and
>in a bow-shaped pattern.  The first and last dampers of the bass
>section lift with the treble dampers, with the dampers in between
>lifting afterwards.  The bass lifter rod is straight, as are the
>hanger hooks.  I'ver tried varying thicknesses of replacement leather
>between the rods, which only change the timing of the lift, not the
>pattern.  Any ideas?    Patrick Poulson, RPT

Dear Patrick,

It is my understanding on a vertical piano to customarily adjust all the
damper levers to the sustain pedal (right) only.  Not the way you
described.  After doing that I am certain you will find the bass damper
sustain pedal (middle) will do what's necessary when operated by itself,
though not necessarily with an even lift.

As for the reason for the bow, I can't help you other than to suggest that
a different leverage is applied to the bass damper lever lift rod when
operated with the right pedal.  Hence, a discrepancy in the eveness of
damper lever lift.

Keith A. McGavern, RPT
kam544@ionet.net
Oklahoma Chapter 731
Oklahoma Baptist University
Shawnee, Oklahoma, USA