IME, it has always been that way and you need to learn to live/deal with
sheet good variances, just as you do with measuring inconsistencies.

When I cut dadoes, it is usually a bunch and I batch cut, so I rarely use
anything but a dado stack in the TS ... routered dadoes are just too damn
time consuming for batch cutting dadoes in 30+ cabinets at a time.

So, with that in mind:

One of my solutions is to buy plywood (an entire project's worth from the
same stack if possible) that closely fits the "project" dado size.

To do this, I keep a number of marked dado "story sticks" in my truck. These
are simply cut off a reject/extra dadoed rail or stile from past projects
and are of a known, repeatable dimension.

http://www.e-woodshop.net/images/Projdado.JPG

Slid down the edges of a sheet of plywood, they give an excellent indication
of what I can expect to deal with from that sheet. (I've been known to do
this to every sheet in a pickup load before it went on the truck).

I also use a Freud dial-a-width dado stack, and I ALWAYS keep the CLEAN
chippers stored in the same order when not in use so that they go on the TS
in the same order everytime.

That way the only thing I have to change when fine tuning a dado for a
particular batch of sheet goods is the number of clicks and the direction
.... (the +7 in the photo above is the number of "clicks" I need to
"increase" a 3/4" set of chippers to repeat that particular width).

I also shoot for tight over loose. A quick hit with 80 grit on both sides of
that 1/4" edge of plywood is usually enough to "force fit" a piece that is a
bit too thick without having to setup a piece of machinery to deal with it.

Nothing is perfect, but the sum of the above can save a lot of time and can
be done quickly, and without much thought/effort necessary.

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Last update: 8/29/06