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Author: deajohn5556
Time: 04/30/10 20:10 PST
This is a reply to message no. 21081 by skydivetaurus
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Formula for calculating the pull-out force of a screw from wood

I would estimate the pullout force as


P = (PI)DtS/2   where PI = 3.14; D = screw diameter; t = engagement length;  and S = shear strength of wood which is around 500 psi, up to 800 psi for hardwoods.  Yoou may want taodd a safety factor of 2 or more to be sure.

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