Workshop
Camera for pitch. Auto-lock nests the comb on crests in the lens. Mic the major Ø to finish — a photo will not split 55° Whitworth from 60° UN.
Auto-lock reads the crests on the centreline and nests the comb on them. It will not read major Ø or split 55° from 60° — mic the OD to finish.
Hold the work side-on, fill the frame, keep the axis on the centreline. Auto-lock nests the comb.
Metric pitch
TPI
Pitch only — several diameters share a pitch. Mic the major Ø to finish.