Spruce Strength/Weight

[Delwin D Fandrich]

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"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).=20
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=20
    psi (white).=20
Compression perpendicular to grain--fiber stress at proportional limit =
(fspl) is 590 psi=20
    (Sitka) vs 500 psi (white).=20
Shear parallel to grain (maximum shear strength) is 980 psi for both.=20

Other than the above I'm sure white spruce has a greater =
"strength-to-weight" ratio than Sitka.

Del


  ----- Original Message -----=20
  From: Richard Brekne=20
  To: Pianotech=20
  Sent: February 05, 2003 5:37 AM
  Subject: Re: Spruce Strength/Weight


  Compression strengths for red, white and sikta spruce at 12 % MC=20
  White 35,700 / 3000=20
  Sitka 37,700 / 3200=20
  Red   38,800 / 3800=20

  FWIW=20
  RicB=20
   =20

    >I thought sitka had a greater strength/weight ratio. And does white =
spruce=20
    >have a greater compression strength?=20
    >=20
    >Terry Farrell=20
    Wood Handbook - Look it up.=20

    Ron N=20

    _______________________________________________=20
    pianotech list info: https://www.moypiano.com/resources/#archives

  --=20
  Richard Brekne=20
  RPT, N.P.T.F.=20
  UiB, Bergen, Norway=20
  mailto:rbrekne@broadpark.no=20
  http://home.broadpark.no/~rbrekne/ricmain.html=20
   =20


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