Hammer Shanks

[Joe And Penny Goss]

Tim,
Do not leave us at the cliff's edge . What were your results. The short
story.
Joe Goss
imatunr@srvinet.com
www.mothergoosetools.com
----- Original Message ----- 
From: "Tim Coates" <tcoates1@sio.midco.net>
To: "College and University Technicians" <caut@ptg.org>
Sent: Friday, November 21, 2003 6:53 AM
Subject: Re: Hammer Shanks


> 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
> >
> >
> >
> >
> >
> >_______________________________________________
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> >
> >
> >
> >
>
>
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