Improved hammer skiving
Problem: Strips of felt that are to become hammers must first be "skived," or trimmed, into a pre-hammer shape so that when the strips are bent in the hammer-making molds, the resulting hammers will be of the correct size and shape. This used to be done using unstable wooden fixtures, and resulted in hammer sizes and shapes that varied from instrument to instrument, which required that more hammer filing be done before voicing in the factory or in the field.
Solution: A proprietary skiving machine (not shown) uses CNC technology to shape the felt strips to the exact specifications originally developed for each piano model so that the hammers turn out the same every time. Very little hammer filing is then needed prior to voicing.
Individual hammer gluing
Problem: Using a special fixture, hammers were glued to the shanks in groups. This was fast and efficient in the short term, but because hammers slightly shift position as the glue dries, they required a lot of adjusting later on. The twisting and bending of the shanks during this adjustment put potentially damaging pressure on the action parts.
Solution: Hammers are installed individually, just as they would be in a rebuilding shop. This is much more labor-intensive in the short term, but is more accurate and eliminates most of the need for later adjusting.
Scale-indexed action-part mounting system
Problem: Action parts were screwed to the action frame by hand, resulting in slight variations in the positions of parts on the frame from instrument to instrument. These variations then had to be eliminated by careful adjustment in the factory or the field.
Solution: Action parts and screws are inserted by a machine indexed to the scale of the piano. Installation is uniform and exact, so there is little or no need for adjustment later.
Institute measures to reduce incidence of sticking dampers
Problem: Stainless-steel damper wires sometimes wouldn't slide freely in the damper guide-rail bushings; dampers would stick in the up position, causing notes to sustain.
Solution: Damper wires are now made of nickel silver, which takes a higher polish than stainless steel, and is more malleable for easier adjustment. They are polished in an ultrasonic cleaner (shown), and the damper guide-rail bushings are impregnated with Teflon powder, which reduces friction to near zero.
Thin high-treble hammershanks
Problem: Steinway wanted to enhance the tonal sustain in the high treble.
Solution: Thinning the hammershanks of the highest 20 notes to reduce their mass and increase their flexibility allows those hammers to rebound from the strings faster, which increases the volume level of their tonal sustain.