Micrometer reading simulator

Notes

• On a metric micrometer the spindle pitch is 0.5 mm and the thimble has 50 divisions, so each division is 0.01 mm. The sleeve has 1 mm lines above the index line and 0.5 mm lines below it.
• On an inch micrometer one turn is 0.025 in and each of the thimble’s 25 divisions is 0.001 in. The sleeve is numbered every 0.100 in, with lines every 0.025 in between.
• Sources show the sleeve of larger metric micrometers both ways: a BMW training booklet reads 139 mm straight off the sleeve of a 125–150 mm micrometer, while an Indian vocational text says every range carries only 0–25 mm on the sleeve and adds 50 mm on a 50–75 mm micrometer. The simulator includes both; always look at the range on the frame first.
• Most sources put the half-millimetre lines below the index line; a KTU (Karadeniz Technical University) course note says some models have them above.
• On inch micrometers a 2-inch micrometer measures from 1 to 2 inches (US Army TM 9-243). No source found says how inch sleeves above 1 in are numbered; the simulator numbers them from 0 and adds the base from the frame.
• Take the reading at the first click of the ratchet and look at the index line from straight on; viewing it at an angle shifts the reading.
• The drawings are made for learning to read: the frame shape and colours are not any maker’s design.