dadiOH wrote:
I used to make lots of them. Now, less because I have more tools but
I still do on occasion and I wonder why they work? We all know that
wood expands and contracts and lap joints have to pieces of wood
doing that at right angles to each other yet they remain nice and
solid. How come?
Someone might say it is because each piece is narrow and doesn't move
much. That is true but I've often made fairly wide laps. For
example, all our toilet seats are wood, each made with four pieces
about 3" wide lapped at the corners.

Discussion is invited.

I'll throw out the thought that it's because the wood does not move at the
joint. The glue successfully holds that joint together as a unit. This
might be easier to see with edge glued boards. The boards may move some
with varying conditions, across their width, just not at the joint where it
is glued.

--

-Mike-