New action-parts problem

[Jim_Harvey@yca.ccmail.compuserve.com]

     John,

     I'm glad to see you checked the key height twice! :)

     I'd be interested in knowing *what* new parts were installed, but
     will take a shot anyway.

     The problem does appear to center around the proximity between
     backcheck and hammer tail. The backcheck doesn't want to "let go"
     in time to permit the key(s) to recycle. I hope I'm understanding
     this correctly. If so, the following thoughts:

     1. Hammer tails possibly conflicting as a result of the boring
     you describe. In other words, the tails are now too long (or too
     low). Dennis Johnson's fix may work, providing you don't have to
     jack up the action unrealistically;

     2. Backcheck *angle*, in addition to your height check. The
     surfaces must match through the operation cycle;

     3. Hammer tail (curve) shape [same idea as #2];

     4. Key flex;

     5. Excessive hammershank flex.

     It's 2:00am. I'll chew on this some more tomorrow when I'm
     fresher.

     Good luck/Jim Harvey RPT
___________ Reply Separator ___________
     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.