So I guess this bit of marketing is much like the creative accounting practices on Wall Street these days? Just manipulate things until they tell the story you desire?
Terry Farrell
----- Original Message -----
From: "Delwin D Fandrich" <pianobuilders@olynet.com>
To: "Pianotech" <pianotech@ptg.org>
Sent: Wednesday, February 05, 2003 12:57 PM
Subject: Re: Spruce Strength/Weight
"Strength-to-weight" ratio is an elusive parameter. What is strength? What are your sources. At 12% moisture content the Wood Handbook gives both a specific gravity of 0.35. (These figures are given for Canadian Sitka and white spruce -- there are no commercially viable stands of Sitka spruce left in the continental U.S.) The most important "strength" characteristics are:
Modulus of rupture is 10,100 psi (Sitka) vs 9,100 psi (white).
Modulus of elasticity is 1.63 x 10^6 psi (Sitka) vs 1.45 x 10^6 (white).
Compression parallel to grain (maximum crushing strength) is 5,480 psi (Sitka) vs 5,360
psi (white).
Compression perpendicular to grain--fiber stress at proportional limit (fspl) is 590 psi
(Sitka) vs 500 psi (white).
Shear parallel to grain (maximum shear strength) is 980 psi for both.
Other than the above I'm sure white spruce has a greater "strength-to-weight" ratio than Sitka.
Del
----- Original Message -----
From: Richard Brekne
To: Pianotech
Sent: February 05, 2003 5:37 AM
Subject: Re: Spruce Strength/Weight
Compression strengths for red, white and sikta spruce at 12 % MC
White 35,700 / 3000
Sitka 37,700 / 3200
Red 38,800 / 3800
FWIW
RicB
>I thought sitka had a greater strength/weight ratio. And does white spruce
>have a greater compression strength?
>
>Terry Farrell
Wood Handbook - Look it up.
Ron N
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Richard Brekne
RPT, N.P.T.F.
UiB, Bergen, Norway
mailto:rbrekne@broadpark.no
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