Slotted "T" beam is cut and bent to secure the blade and to provide the miter and square reference surfaces.
Known example marked: Hibbards True Value Pat. 5-5-31
Known example marked: SOHACO/SOUTHINGTON/HARDWARE CO./PATENTED 5.5.31
Known examples marked: Craftsman with Patented 5-5-31 also stamped on the tip of the blade.