One photo → fastener type, standard (DIN · ISO · UNC · NPT), size range and where to buy the replacement. The digital thread checker — honest answers, never made-up precision.
Verified on our labeled hardware-store benchmark, July 2026. We publish our numbers — ask any other scanner app for theirs.
No calipers, no thread charts, no guessing at the store counter.
Any coin in your pocket becomes the ruler — the app knows each one's exact diameter (a quarter is 24.26 mm). A plastic card works too, and is even more precise.
The AI reads head shape, drive, thread profile and the coin next to your part — then matches it against real DIN/ISO/ANSI spec tables, not vibes.
A confident match, a short list of likely ones, or two smart questions — with a size range, never a fake decimal point.
Scanner apps die by guessing — users measure the part, catch the lie once, delete forever. BoltSnap tells you exactly how sure it is:
When confidence is high and verified against spec tables: type, standard, size — one card, done.
When look-alikes exist (M8 vs 5/16"), you get the shortlist with one-line differences. The truth is in there — 100% of the time in our benchmark.
Thread pitch can't be read from a photo — anyone claiming otherwise is guessing. We ask two smart questions or hand you a free printable gauge.
Every answer can export a 100%-scale printable gauge: diameter circles, metric pitch combs, TPI combs — with a built-in ruler and a quarter-circle to verify your printer didn't cheat.
Download the gauge (PDF, free)The two tables everyone googles from the garage. The app knows every row offline — but bookmarks are free.
| Wrench | Bolt | Pitch (coarse) |
|---|---|---|
| 8 mm | M5 | 0.8 |
| 10 mm | M6 | 1.0 |
| 13 mm | M8 | 1.25 |
| 17 mm | M10 | 1.5 |
| 19 mm | M12 | 1.75 |
| Wrench | Bolt | TPI (UNC) |
|---|---|---|
| 7/16" | 1/4" | 20 |
| 1/2" | 5/16" | 18 |
| 9/16" | 3/8" | 16 |
| 3/4" | 1/2" | 13 |
| ⚠ M8 and 5/16" look identical — that's the trap the app catches | ||
No — and neither can any app, that's optics. BoltSnap narrows it to the diameter, then settles pitch with one question or the printable gauge. Apps that claim pitch from a photo are the reason this category has one-star reviews.
Photos are processed to identify your part and not kept. Contributing a photo to improve the recognizer is a separate, explicit opt-in — per photo, off by default.
First scans are free, then a small subscription. Cheaper than one wrong bolt run to the store.