"Pete Becker" wrote in message
...

I don't think that's right. Let's take some big numbers to make it
clearer: you set the jig so the blade is 2" away from the face of the
jig. You run a 3" thick piece through it, once from each side. Ignoring
the saw kerf, you end up with a 1" tenon. Now you run a 4" thick piece
through it, once from each side. Both cuts are 2" from the sides, i.e.
right in the middle. No tenon.

--

Ok this is getting funny... we are knocking heads

Try it on your saw... if you don't have a jig, simply try it with your
fence and a 1x board on edge.
Be sure that most the board is between the fence and the blade. Rip a line.
Turn the board around and rip another line. Now do the same with a piece of
2x stock and if you do it right or under stood me correctly,, you'll see
that both left over tennons on each board is the same width.

Remember to cut on the side closest to the blade if you cut on the side
clossest to the jig or fence the tennon will change in size if you change
thicknesses of boards.