Steel Rule Clamp-On Square Head
A clamp-on combination-square head that fits any flat steel rule 12–32 mm wide and up to 2 mm thick. It gives the rule a 90° reference face and a 45° mitre face, so a loose ruler works as a try square, mitre square or depth gauge. The head is 80 x 38 x 18 mm. An M5 bolt runs through a 5.5 mm clearance hole into a captured M5 hex nut (8 mm across flats, pocket allows up to 5 mm thick) and locks the rule against the slot's end wall. The 90° face prints on the bed, so it comes out flat.
tool combination-square layout steel-rule