B58-186 BLOCK PLANE. Mathias Mayo. Mayo is best known as the guy who improved the Phillips patent plow, but he also manufactured these block planes, which are far more rare. 8-1/8" sole, pivoting lever cap. The original cap screw with ornate engraved "M" doesn't hold the cutter firmly, and the cutter is a replacement from a Union Tool plane. It's also kind of grungy overall. Still an extraordinarily rare plane despite its issues. From the Bud Steere collection. Good 800-1200