B67-541 BENCH PLANE. Hardt Patent. Louis Hardt of Yuba City, CA, patented this thing in 1893. It featured a nose piece that slides on an inclined plane to adjust the depth of cut. The patent shows a wooden plane, but the very few known examples are all cast iron. This is the 11-1/2" smoothing plane size, identical to the one shown in Figure 263 of PTAMPIA I, except with a high knob. Like all known examples, has a marked Sargent cutter and a Sargent frog. It also has "Hardt" and the patent date cast into the toe and "Hardt" cast into the underside of the lever cap. Japanning about 25%, small chip from the end of the tote but wood otherwise very clean, cutter and chipbreaker have light surface oxidation. A very nice example of one of the holy grails of patented plane collectors. From the collection of Harold Unruh. Good+ 3000-6000