"Vince Heuring" wrote in message
om...

SWMBO wants me to make some plywood boxes that she will then upholster.
They will be used for people to sit on (don't ask).

How about some construction ideas? They need to be sturdy, and thus
will need some kind of internal reinforcement.


No need for internal reinforcement if there's a designated top and bottom.
Box joint sides - use a router jig with a spiral bit and backer board for
negligible tearout - fully glued and flush trimmed top and bottom. If no
designated top or bottom, I'd rabbet in the ends.

Made some 1' x 1' x 1' boxes for robotics out of that thinner than 1/4
five-ply underlayment, using 1/4" bit, and in the load direction, they could
hold a ~300 lb TA I caught using one as a stool....

Half inch with good ply, 3/4 with voids will do anything, I should think.