"redbelly" wrote in message
ps.com...

Mike Dembroge wrote:
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.

Mike, I have two comments:

1. Are you sure the slots were cut to the same width? Might be worth
checking them with a pair of calipers, for consistancy in cutting
width.
The slots were cut on the TS using a Forrest stacked dado set. The problem
was with the plywood thicknesses.

2. If the less than 0.009" gap results in an acceptable amount of
slop, could you insert a thin shim to fill in the gap? It wouldn't
need to fill in along the entire length, just a 1/2" wide piece every 6
or 12 inches or so.
The problem with using shims is that they look pretty sloppy. One project
was a Mahogany desk for a yacht, so it really had to be right.

Regards,

Mark