Drill Bit Diameter Gauge Block

A tidy bench block that tells one drill bit from the next at a glance. This is a practical workshop tool rather than an ornament: a rounded-corner rectangular bar drilled with two rows of test holes and engraved with their diameters. The top row runs Ø1, Ø1.5, Ø2, Ø2.5, Ø3, Ø3.5 and Ø4; the bottom row continues Ø4.5, Ø5, Ø5.5, Ø6, Ø6.5, Ø7 and Ø7.5 — a full sweep of metric sizes in half-millimetre steps. Drop a loose bit, dowel, rod or wire into the holes until it slides snugly and you have read its diameter without reaching for callipers. It lives on the bench or wall of any workshop, garage or maker space, and doubles as a quick calibration check for your printer or router: if the printed holes come out to size, your machine is dialled in. Print notes • Print flat, label-side up, with the holes running vertically so each bore stays round and true to size. • Dimensional accuracy is everything here — run a tolerance/flow calibration first, since holes typically print a hair undersize; scale hole diameters slightly if your printer shrinks them. • No supports are needed; the engraved text reads best with a fine nozzle and a modest layer height. • PLA is fine for reference use; PETG or ABS resists knocks and workshop wear. A brim keeps the long bar from lifting at the corners.