There should be no mystery associated with 3D printing player piano
parts.  My son and I have collaborated several times to produce parts
using both filament and thin-layer 3D printing with excellent results.

Any hobbyist with a slightly better than entry-level filament printer
and a working knowledge of free or very inexpensive CAD software can
produce almost any small part with ease.  Our favorite CAD software is
AutoDesk Fusion 360 which is free to hobby users.  We have produced
gears, valve seats, Ampico B expression grids, etc.  Attached are
pictures of some of the items we have produced.

John Kelsey

 [ Note the threads in the setscrew hole. Thin-film printing has
 [ resolution sufficient to print usable threads.
 [ http://www.mmdigest.com/Attachments/20/02/12/200212_135315_Gear%20CAD%20rendering.jpg 

 [ Lapping on 600 grit abrasive paper creates a polished, smooth
 [ surface.
 [ http://www.mmdigest.com/Attachments/20/02/12/200212_135315_Valve%20seats%20before%20lapping.jpg 

 [ Lapping on 600 grit abrasive paper creates a polished, smooth
 [ surface.
 [ http://www.mmdigest.com/Attachments/20/02/12/200212_135315_Grids%20before%20lapping.jpg