I was cutting through a small box, abot 10" L by 6" W on a table saw.
Whoever saw the procedure from Freedman's book on box making, that's
about what I was doing: Make a cut on long side, tape it, shim it, do
the other long side, tape it, shim it , and then do the short sides.
Problem is, the cut on the short side cuts into the already cut long
side - in other words, I can't get the flush cut after cutting all four
sides. The fence didn't move, I tried both ripping and crosscutting
blades (Freud, so that shouldn't be the issue). I also used a jig,
similar to the one for tennon cutting, to provide adequate support.
Basically, the only reason I can think of is that the box surface that
presses against the fence during the cut is not perfectly flat,
preventing the flush cut on all sides. Can you think of anything else
causing this?