On Wed, 5 May 2021 14:29:45 -0700 (PDT), DerbyDad03
wrote:

On Wednesday, May 5, 2021 at 4:45:06 PM UTC-4, jboisver wrote:
A good rule of thumb is that the screw should drive through
to about half the thickness of the bottom piece.
So a 1" thick piece being screwed to a 2" thick piece should have a 2" screw.


I need to hang some 1/4” luan on a 6 x 12 beam. I guess I need a 6” screw.
Oh...wait...the bottom piece will be the luan. I only need a 1/8” screw.


Good one.
.... I guess that good-rule-of-thumb
was just pushed into the table saw blade ! :-)
John T.