"Lew Hodgett" wrote in news:54af5caf$0$11351
:

Use rail & stile construction.

Make rails and stiles from 3/4" x 2" poplar.

Make the panels from 3/4" plywood.

You now have a cupboard door that is strong enough that you can
mount things on the inside surface.

If the plywood is not a full 3/4", you will need to run the 3/4" x 2"
poplar thru the planer to match the plywood thickness.

I presume your intention here is to simply rabbet the plywood
to fit the groove in the frame - as opposed to a bevel or any
other sort of profile on the panel?

If it were me, since these are shop cabinets, I wouldn't
worry about matching the frame thickness to the panels. It
won't hurt if the frame is 1/8th proud of the panel. If
you really cared, offsetting the rabbets slightly would let
the front face be flush.

Actually, I'd probably go with thinner ply for the doors,
to make them lighter and easier on the hinges. Unless the
panels are huge, 1/2 or even 3/8th would be stiff enough
to hold a rack of screwdrivers or whatever mounted on the
inside

John