Steinway damper stop rail reg.

[Bill Spurlock, RPT]

Jeff Stickney wrote:
> if you regulate the
> stop rail according to damper height with the pedal, you have dampers
> jumping up and down on the keys with a hard blow.  If you regulate the stop
> rail according to lift with the key, then when the pedal is activated, the
> key jams the damper lever up into the stop rail.  Have ya'll experienced
> this, and if so, what is the solution?

Because the pivot point of the damper lift tray is not in line with the damper
lever flange centerpins, the amount of damper lift from the key is greater when
the pedal is also depressed, than the lift by the key alone. What happens is
this: the key lifts the forward end of the damper lever a certain amount; then
when the pedal is depressed, the damper flanges (back ends of the damper levers)
are lifted slightly higher. This causes the damper top flanges to be lifted
slightly higher. My drawings and full explanation of this are in the 6/91 PT
Journal, pgs. 19-21. I have never been able to find out the reason for this
design. Almost all other manufacturers place the damper flange centerpins
exactly in line with the damper tray pivot pins, eliminating this problem.

When adjusting the Steinway stop rail, the best you can do is minimize the
discrepency in lift between the pedal & key, and the key alone situations. Do
this by keeping the total amount of damper tray movement to a minimum; i.e.
minimize lost motion between tray and levers, and limit pedal travel so damper
lift with the pedal is no higher than the damper lift from the key alone. The
less the damper tray moves, the less the rear ends of the damper levers raise,
and thus the less additional damper lift occurs when the pedal and keys are used
in combination.

As Jeff points out, one consequence of this design is that the stop rail must be
set high enough to accommodate the damper levers when key and pedal are used
together, and this leaves more clearance than we'd like when dampers are lifted
by keys alone. One modification that can be made to reduce this discrepency is
to space the damper stop rail forward as close as possible to the top flanges,
using a washer or two between the stop rail and the piano belly. The
above-mentioned Journal article diagram reveals why this is so.

Bill Spurlock