Bolt Diameter And Pitch Gauge Board
A 150 x 58 x 8 mm bench board that identifies unlabelled bolts: nine ascending go-holes (4.3, 5.3, 6.3, 6.65, 8.3, 9.85, 10.3, 12.3, 12.95 mm — the smallest hole a shank passes gives its nominal diameter, including 1/4", 3/8" and 1/2") plus eight 24 mm thread-pitch combs on 3 mm raised ribs — top row metric 1.00 / 1.25 / 1.50 / 1.75 mm (M6, M8, M10, M12 coarse), bottom row imperial 1.27 / 1.41 / 1.59 / 1.95 mm (1/4-20, 5/16-18, 3/8-16, 1/2-13). Diameter plus pitch together separate metric from UNC, which a hole-only sizer cannot do; two 4.5 mm holes take M4 screws to mount it to the bench or a pegboard hook.
tool gauge fasteners bolts