Is what you want to do is miter the edge of two pieces of plywood and glue them up so the plys don't show as in a furniture carcase?
If you are just ripping a piece of ply on the fence you are almost never going to get a perfect result.
When we do something like this at work we usually cut up the pieces square and to the correct size on the cnc or saw (no miters on edges).
After we cut the blanks we run the edges against the sacrificial fence on a table saw with the blade being on a 45' and buried in the fence.
This can also be done on a shaper or router table with a 45 bit or knives. This alows you to have either a feather board to keep the ply dead flat against the table of the machine. If I was on a saw I would set the angle just a HAIR heavy. We would also at work try to use veneered MDF as opposed to ply if possible (more consistant thickness).
If you use a saw the blade has to be sharp, and you may get better or worse results depending on the number of teeth on the blade and the tooth style. If I remember right we get the best results from an ATB blade (alternating top bevel).
Glueing up a mitered carcase is another art unto itself
Last edited by Snaglpuss; 02-02-2013 at 10:49 PM.