Preview — does the thread fill the frame and look sharp? Tap Use photo to continue, or Retake.
Hold the phone directly above the fitting, lens parallel to the surface. Fill the frame with the thread but keep it sharp. Side light makes the crest shadows pop.
2Review & identify
Auto-detected pitch:—
Optional — set a scale for real mm sizes (tap a ruler in the photo):
Get a reliable reading
The #1 reason a photo-measurement is wrong: the part and the scale were not placed steadily / on the same plane. Follow this checklist:
Lay the fitting and the ruler flat on the same surface (one table / one board).
Hold the phone directly above them, lens parallel to the surface — not tilted at an angle.
Keep the phone steady: rest it on a stack of books or a small tripod. Hand-shake ruins the scale.
Put the ruler and the thread at the same distance from the lens (same height).
Fill the frame with the thread but keep it sharp — tap to focus before shooting.
A side light (desk lamp) makes crest shadows pop, which helps auto-detection.