I'm having an issue with cutting the tenons and open mortises on some window sashes that I'm throwing together for a chicken coop and hoping you guys can help. When using my tenoning jig on the table saw, the leading edge of the piece that I'm cutting appears to cut straight and vertical. However, as the blade exits the backside of the cuts, it seems to cut a little bit more off at the bottom left side of the joint. Hopefully the picture below shows what I'm trying to describe. The red line is the corner that gets removed from the backside of the cut after the wood exits the blade; the front side of the cut remains square.
tenon.png
Does anyone have any ideas what might be causing this? It almost seems like the blade is flexing as I make the cut, however the problem happens regardless of the rate that I feed the material through, and no matter what blade I use. I can detect a slight wobble when spinning the blade by hand which appears to be due to some play the arbor and/or motor shaft. If wobble was the issue, wouldn't cutting slower then fix that since it would let the tooth that is farther out finish its cut?