This patent is the earliest American patent for a metallic plane, and it features prominently in both volumes of Roger K. Smith's books, “Patented Transitional and Metallic Planes in America.” According to Vol. I of PTAMPIA, “Apparently many other planemakers manufactured this type, either with or without license, because similar planes are known of various sizes and with minor design changes.” PTAMPIA Vol. II presents research relating to the manufacture of this design, including the fact that the known examples of the jointer plane also have Foster's patent 3,355 for a piece of soapstone inlet into the sole; in fact, Foster's patent, granted after this patent had already expired, shows a plane very similar to Knowles' design. Several other Knowles patents were not restored after the 1836 patent-office fire: “Springs for carriages”, 1825-11-04; “Mode of covering buildings”, 1828-10-11; “Manufacturing wood screws”, 1833-03-01; “Carriage to overcome obstruction in roads”, 1833-08-29.

(To be filled in.)

• USPTO pdf
• "Vintage Machinery" entry for Hazard Knowles