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
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