New action-parts problem

[Don Mannino]

John Minor wrote:

>>    A local top-quality rebuilder has installed new NY parts in a Steinway D
and is having some unusual problems. The owner of the
instrument is a concert pianist with high technical demands.      Here is what
happens: On fast repetition, the hammer gets stuck in
the backcheck before the jack re-sets. We've check:

Key height
Dip
Hammer travel
Center pins
Backcheck height
spring tension
let-off and drop
jack to knuckle
jack in window
Key height

Anyone else have this problem with the new NY problems. Could slight
change in hammer bore + - 3/16 affect this.<<

Yes, the hammer bore could affect this. Also the length of the hammer tails and
their relationship to the backchecks could effect this.

If you check the shank position at rest, it is probably too high off the rest
(rebound) cushion. If the action is regulated with the shank lower, the problem
will probably disappear - but the blow might seem excessive.  Since Steinway
technicians (I don't have a Steinway manual here to check if this is the
"official" method - I think it is) usually recommend that the capstans be
regulated so that the shanks are ~4mm off the rest cushion, then the key dip
must be increased to compensate and give equal aftertouch. If this action is
regulated this way, then the repetition problem might be lessened or eliminated.

The problem is sometimes created by a slightly high string plane, where the
hammers are regulated for correct blow distance from the strings. The hammer
shanks end up too high at rest, and the balanciers have trouble supporting the
shank correctly during use, so that the hammer drops below rest and jams on the
backcheck during rapid repetition.

This problem can also be created by short hammer tails / low backchecks, but the
root cause is usually "incorrect" hammer bore distance for the string height of
that particular instrument.

I learned about this problem myself the hard way some years back, also on a D.
There was also an article in the PTJournal in 1984 (I think) suggesting an
unusual "work around" for this problem involving lengthening the hammer tails.

Don Mannino RPT
74473.624