B58-747 BUTT-LOCKING BEVEL. Smith & Duckworth. Patented in 1883 by James Duckworth and Eli Smith of Springfield, MA. The blade has a groove milled in it which allows it to be quickly locked at a 90 degree angle. This is a very uncommon bevel, and in the few previous examples we've seen the blade is locked in the 90 degree position by a thumb slide on the handle, and there is a conventional large locking thumbscrew on the end. This one has two small screws on the end, which require a screwdriver to tighten. One has the head partly broken. It's also missing the brass scale with degree markings around the pivot screw that other examples have. Possibly an early variation on what is already a rare bevel. Heavy iron handle, 5-3/4" long, with 7" square cut blade. Good+ 200-400