A fake Audemars Piguet 26470O gives itself away in four places: case size, dial texture, caseback engraving, and movement beat rate. The 26470O is a 42 mm Royal Oak Offshore chronograph, so a counterfeit that measures 43 mm or more across is wrong before you even look at the dial. Work the checks below in order and stop at the first failure.

Prerequisites

  • Digital calipers that read to 0.01 mm
  • 10x jeweler loupe and diffused light
  • Timegrapher, or a watchmaker who owns one
  • Catalog photos of the exact 26470O variant for side by side comparison

Step-by-Step Check

  1. Measure the case across the bezel at 3 and 9 o'clock. Genuine 26470 cases read 42.0 mm; most fakes read 43 mm or wider.
  2. Measure thickness from the caseback to the crystal. Genuine examples sit near 14.5 mm; copies run thicker because of a spacer ring over a generic movement.
  3. Place the loupe on the dial and study the tapisserie squares. Mega Tapisserie pyramids have flat tops and sharp edges; fake dials show rounded bumps or a printed grid.
  4. Inspect the applied AP monogram at 12 o'clock. The letters should sit level with clean edges and a polished bevel.
  5. Compare the three subdials at 12, 6, and 9. Hands should be flat with a snailed center, and subdial rings should be metal, not printed lines.
  6. Look at the date aperture. Corners are square, and the numerals sit centered in the frame.
  7. Press each chronograph pusher. Genuine pushers travel with even resistance, screw down, and reset to zero without wobble.
  8. Turn the watch over and read the caseback. Engraving is deep, filled, and even, with the reference and case numbers on separate lines.
  9. Clip the watch to a timegrapher. Calibre 3126/3840 beats at 21,600 vph; a copy running 28,800 vph on a modified 7750 does not match.
  10. Study the movement through the sapphire back with the loupe. Rotor engraving, bridges, and decoration should match reference photos.
  11. Check the strap and clasp. Hornback alligator has large square scales, and the folding clasp carries correct AP engraving with tight spring bars.
  12. Send the serial and case numbers to an Audemars Piguet service center for a written verification.

Common Tells at a Glance

  • Bezel screws that sit proud of the bezel or line up at the wrong angle
  • Spelling errors or uneven spacing in the caseback text
  • Date wheel font that is too wide or sits off center
  • Rotor that spins with a rattle when the watch is shaken
  • Caseback screws that show tool marks from a bench opening

Before You Pay

A watchmaker with an AP parts account can open the case and confirm the movement in minutes. Papers, box, and a service invoice do not prove a watch is real, since those items are copied as well. Buy from a seller who accepts a return window long enough for an independent inspection, and keep the written verdict on file if you ever resell the watch.