Rib dimensions

Farrell mfarrel2@tampabay.rr.com
Thu, 11 Dec 2003 07:00:03 -0500


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Lots of good methods for calculating the radius of an arc have been =
provided. But there is also the question of whether the curve is a true =
arc or some other shape (this assumes you have a specific shape as a =
target). Most of the provided methods do not address that concern - in =
fact you could have an obtuse angle with two straight sides rather than =
an arc. That's why I suggested making a number of measurements along the =
curve - offsets from a straight line.

Terry Farrell
  ----- Original Message -----=20
  From: Absolute Piano=20
  To: pianotech@ptg.org=20
  Sent: Wednesday, December 10, 2003 4:40 PM
  Subject: Rib dimensions


  Hello,

  I'm trying to apply some science to my soundboard rib making and I am
  looking for "tables of static values for  the Resisting Moment (W) and =
the
  Moment of Inertia (I) for all the possible cross sections of sugarpine =
and
  spruce (DIN 1052 Class I will suffice).

  What is the formula for converting pounds/inch squared to kg/cm =
squared?

  Given a right angle connected to the outside of an arc of a circle, =
how do
  you prove the circle is 60'? (I made a jig for crowning ribs that is
  adjustable and I want to calibrate it.

  Thanks,

  Jude Reveley, RPT

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