B59-183 BENCH PLANE. Union Mfg. No. X4-3/8. The X signifies Carleton's vertical post adjustment, patented in 1903. Stanley offered the No. 4 and 4-1/2, Union went them two better by adding the 4-1/4 (2-1/8" cutter) and the 4-3/8 (2-1/4"). Why Union thought an extra 1/8" in cutter width was worth adding a whole new model with its own casting is unclear; it may help explain why Stanley is still around and Union isn't. ?Japanning complete, original marked cutter, slightly spalled, wood near perfect. Fine 200-400