I just finished drawing up some plans for some file cabs made with "3/4"
plywood. Trying to draw to these dimensions is impossible. I built in a
little extra clearance to compensate for the missing wood. Frustrating.
It's started me thinking why? Why can't they make 3/4" plywood 3/4"?
Because they can get two veneer layers where they used to get one? Because
it is measured in millimeters when everything else is is imperial? (who came
up with that brilliant scheme.) Why can't they anticipate the thickness
before sanding. Slight variance within the sheet is acceptable and
understandable. But dealing with these minute dimensions in the design stage
is very frustrating.
Rant mode off.

"Mike Dembroge" wrote in message
om...
For those of you that use a lot of plywood in your cabinets, casework,
etc, what do you find as an acceptable amount of thickness variance in
your sheet goods?

My last 3 projects all used plywood of various species (A-1 Mahogany, A-2
Maple, C-2 Maple), and all was purchased from the same source: PALS in
Oakland, CA. However, I found with each project that the thickness of the
plywood varied not only between sheets, but within the same sheet as well.
On my last project, I measured .009" difference in about 25" of length in
a sheet. While this doesn't sound like a lot, it was enough to create a
sloppy dado at one end and a too-tight-to-fit one on the other.

Am I being too fussy, or is this normal? I spend a fair amount of time
setting up the stacked dado set to produce a clean-fitting dado that is
not too sloppy and not so tight that it distorts the material. So, when I
make several cuts and some don't fit, it's a PITA.

Mike
Alameda, CA