If you make a wooden slide with two or three hold-down clamps of type shown below (toggle clamp), you don't need a fence for your router cut (router on table saw extension), so an uneven cut on the opposite side will not matter. A well-fitting wooden strip runs in the table saw mitre head groove for alignment under the slide. I use a candle to wax the wood runner for a smooth slide action.
I also use this method for home-made fretboards using the saw blade. Lay out the fretboard as a rectangle, and make the frets via a square on the edges to be cut off, then cut the taper. Draw the taper line to be cut, in pencil, for measurement purposes.
If you initially cut the slightly overwidth slide with the saw (or router), with the wood strip running in the track, the edge will be at the exact position of the blade. Then you just line up the fretboard pencil line with the edge of the jig. If the saw blade is sharp and fine, you get a straight, clean edge.
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Not in PSG context, but I use a longer jig of 1/4 inch ply, with a guide strip along the top, left-hand edge in conjunction with a (*dangerous) hand-held rotary saw to cut doors, and 4x8 ft ply, etcetera. No need to measure blade offset, since the saw initially cut its own jig edge.
Naturally, the bottom slide, and hold-down clamps are not used with this jig. C-clamp, or spring clamp the straight edge to the work piece, or use screws if you can tolerate screw holes in the back of the work. Cut with good side down, since this saw cuts upward and leaves a splintered top edge.
Throw a dozen 3/4" small scrap chunks under the work to hold the 4x8, or whatever, off the work bench so you don't slice the bench.
*Caution with these rotary saws. One caught in my dad's loose-fitting overalls and sliced into his leg, just missing a tendon. Lots of blood and hamburger!
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