Cone burr and shaft: the part the ring movesOuter burr, cut away a quarterLoupe reticle: 0.1 mm a divisionA hand grinder taken apart along its shaft. The cone burr turns inside the fixed ring burr; beans fed from the hopper are cracked in the wide throat and finished between the two flat lands at the bottom, so nothing leaves larger than the gap between them. The stepped ring under the carrier threads onto the shaft's 1.2 mm pitch and clicks 40 times a turn: each click draws the cone 30 µm down and opens the gap by 30 µm, from 0 at the zero point to 1.2 mm after one full turn. The loupe shows the outlet at 10× against its 0.1 mm reticle; the grounds in the cup are drawn at their median size, about 0.8 of the gap.