How to measure
- 1Ø over threads. Close the outside jaws across the thread crests (the peaks). Rotate the part and take the largest steady reading.
- 2Pitch. Don't trust one tooth. Line the jaw on a crest, count N crests, read the length, enter both in the span box — pitch = L/(N−1). Vital for fine threads (SMA = 36 TPI).
- 3Depth. Optional. Depth-gauge crest→root, or (Ø crest − Ø root)/2. Helps separate 60° / 55° / round forms.
Measure
Measure Ø over the thread crests with caliper jaws.
or span:
mm over
crests
More accurate than single-pitch: measure crest №1 → crest №N, pitch = L / (N−1).
mm
Used to sanity-check thread form (60° V vs 55° vs trapezoidal vs round bottle thread).
Decimal comma or point both accepted. External threads normally measure 0,05–0,4 mm under nominal (more on coarse pitches) — the matcher accounts for this.
Candidates
Enter at least the diameter over threads, then hit Identify.
Pitch narrows it down a lot — close twins exist (e.g. M8 vs 5/16-18 UNC, M5 vs #10-32 UNF, G1/2 vs 1/2 NPT).
Pitch narrows it down a lot — close twins exist (e.g. M8 vs 5/16-18 UNC, M5 vs #10-32 UNF, G1/2 vs 1/2 NPT).