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noxpurt wrote:
How can I determine or lookup the load ratings or the load failure point
for
a fir plank that is 2 (1.5)" x 12 (11)" x 40"? The plank is oriented
widest
side up and level and the load is against the flat side while being
supported with 1.5" ledges on each side.

thank for any tips

Point load or distributed load?

GIven the ineffective orientation it may be that the deflection of the
beam
will be unacceptable long before it breaks, unless you are intentionlly
using it as a spring. If it is loaded to failure, it will fail in
tension, starting
near the middle of the lower surface, uness a point load crushes
fibers in the upper sruface sufficiently to precipitate compressive
failure.

Fredfighter,

2x12 doug fir is plenty strong. A 40" length of it should be able to hold a
few hundred pounds without breaking.
Compressive strength is high too. It would have to be a particularly nasty
point load to crush it enough to make it fail.
Or are you just trying to scare him?