B66-65 SAW DEPTH GAUGE. Flynn Patent. Patented by John Flynn of Philadelphia in 1922, 18" long with two folding arms that slide over a saw blade and can be clamped to set the depth of the cut. It was manufactured by the Universal Depth Gauge Co., presumably one of those one-product companies formed to realize an inventor's dream that promptly vanished when the tool buying public failed to appreciate it. In immaculate condition, with the nickel plating almost completely intact, and clearly marked with the patent date and manufacturer. The only one we've ever seen. Fine 100-200