[CAUT] Shimming the Steinway Action Stack

[Andrew Anderson]

Measurements as follows:

Left to right string height, measured at each break.
Bass 8&1/16" to 8&1/8"  Tenor 7&13/16 to 7&7/8  "alto" 7&7/8 to 8"   
treble (across the break) 7&15/16" to 7&7/8"

Hammer Bore: bass 2&3/16"  tenor 1&13/16" to 1&3/4"

Hammers were sanded and polished, presuming circa 1/16 to 3/32 wear

hammer tail length measured from center of shank to tail  bass 1&3/16"  
tenor up 1&1/16

hammer shank flange center pin height 5&13/16" consistent

wippen center pin height 3&5/16"

action spread 4&3/8"

drop screw clearence below pinblock & stretcher >=5/32"

hammer blow distance varying from 2&1/16" to 1&15/16" in high treble

key dip is 7/16"

let-off is 3/32"

damper timing: 9/16" hammer rise

The work (except sanding the hammers) is factory and the regulation is  
the dealer tech.'s

Capstan height above key is circa 9/16"

magic line capstan cushion intersect at 3/16" dip in the treble and at  
pretty much full dip in the bass.

 >= 3/32" gap between keys and thick fallboard felt.

Those are the measurements of the beast.  Of-course a "slow/sluggish"  
action is only half the problem.  The other is a sweet shy tone  
available with a karate chop in the mid treble.

Andrew Anderson