"Pounds on Wood" wrote in message
...

wrote in message
oups.com...
When it dries, why do you think wood splits from the center to the
perimiter? I think I have finally worked it out, just wanted to know
what you all think first

Dean


I think the easiest way to understand it is this - think of a flat sawn
board. As a woodworker, you know the board will shrink most in width, a
little less in thickness, and almost not at all in length. It is the
difference in shrinkage between width and thickness that matter. Then
think
of that board within a round log. Because the log is shrinking radially
greatly, but in diameter only slightly, the fibers are pulled apart
radially
around the log.

Not a scientific explanation, but an easy one to grasp.


Also a bit backward. As the FPL says, the shrinkage tangentially is
greatest. Thus the radial checks - perpendicular to tangential force.

Take a log and measure a chord which does not cross latewood near the
center. Let's say it's an inch at best at 20 years. Now go out near the
outside and measure a chord of say 5 inches at seventy. With a 10% rate
of shrinkage, it means the interior wants to lose 1/10 of an inch, the
farther, 5/10. The difference is made up in open air as the radial split
opens.