Hammer Shanks

[Tim Coates]

The question I see is this:  So?

Jim are you trying to prove one type of shank makes the best sound by 
testing something besides sound?   The assumption seems to be the 
stiffer the shank the better the sound.  Measure the quality of the 
sound with good software and good recording equipment.  I bet even RCT's 
Pianalyzer will show a tonal difference between shanks (actually I know 
it does because I did those tests a year ago).  


Tim Coates
University of South Dakota
University of Sioux Falls   


James Ellis wrote:

>Gentlemen, and Ladies too, if any of you are following this discussion
>among us fellows:
>
>I said I would make some hammer-shank measurements, and I have done that.
>Due to time limitations, I have only measured four shanks so far.  They
>are:  1) a pre-1920 round New York Steinway,  2) a modern round New York
>Steinway, 3) an octagonal Renner, and 4) a thinned treble shank,
>manufacturer unknown.
>
>I measured the dimensions, the effective weight of only the shank measured
>at 5 1/8 inch from the center (Stanwood would refer to this as the "strike
>weight").  And last of all, I measured the amount of bending.  In listing
>the dimensions, I am referring to that wide portion of the shank where the
>knuckle is glued as the "knuckle stock".  To measure the bending, I firmly
>clamped the shank at the knuckle stock, hung a one pound weight at 5 1/8
>inch from the center, and measured the deflection at the 5 1/8 inch mark
>with a dial indicator.  I drilled a hole in the block to which the knuckle
>stock was clamped to receive the knuckle, in order to firmly clamp the
>stock.   The results are as follows (all measurements are in inches).
>
>N.Y. Steinway, pre-1920, maple
>Knuckle stock:  H = 0.255	W = 0.472
>Round shank, tapered 0.243 to 0.200 at 4.75 from center.
>Strike weight:  1.3 gram
>Vertical bend:  0.059"
>
>N.Y. Steinway, modern, maple
>Knuckle stock:  H = 0.260  W = 0.475
>Round shank, tapered 0.260 to 0.220 at 4.75 from center.
>Strike weight:  1.7 gram
>Vertical bend:  0.035"
>
>Renner octagonal, hornbeam
>Knuckle stock:  H = 0.240  W = 465
>Shank, octagonal, uniform, no taper:  0.240
>Strike weight 1.6 gram
>Vertical bend:  0.061"
>
>Thinned treble shank, make unknown, wood unknown.
>Knuckle stock:  H = 0.240  W = 0.465
>Shank, oval, uniform, no taper:  0.235 x 0.1875
>Strike weight:  1.7 gram
>Vertical bend:  0.065"
>
>I considered measureng the torsion stiffness as well, but that would have
>required another setup, and considerably more time.  The results speak for
>themselves.  If we are interested in stiffness - vs - weight, the round
>tapered shank is definitely superior to the non-tapered octagonal shaft.
>Little is gained by the octagonal shape, and much stiffness is lost by not
>having a larger cross section near the knuckle.  We are dealing here with a
>lever, not a structural beam.  Whatever you might or might not say about
>Steinway, New York, they obviously have the right idea here.  The shank is
>stiff where it needs to be stiff, and light where it needs to be light.
>That design make good sense to me.
>
>Sincerely, Jim Ellis
> 
>
>
>
>
>_______________________________________________
>caut list info: https://www.moypiano.com/resources/#archives
>
>
>  
>