Quick answer
Patek Philippe built the reference 1518 from 1941 to 1954. Total output was about 281 watches. Four are known in stainless steel. The rest are yellow gold or pink gold. A real 1518 sells at auction for six to eight figures. No factory ever mass produced a copy. Almost every fake 1518 falls into one of four groups: a modern custom build, a franken watch with mixed parts, a generic chronograph with a printed Patek dial, or a photo used in a scam listing.
What the reference 1518 is
The 1518 is a manual wind wristwatch with a chronograph and a perpetual calendar. Patek Philippe calls it the first serially produced perpetual calendar chronograph.
- Case diameter: about 35 mm.
- Movement: calibre 13-130, built on a Valjoux 23 base.
- Dial layout: 30 minute counter at 3 o'clock, running seconds at 9 o'clock, date and moon phase at 6 o'clock.
- Crystal: acrylic.
- Caseback: reference number and case serial stamped inside.
Why copies of the 1518 are rare
The 1518 pairs a perpetual calendar with a chronograph. That takes a complex module and hand finishing. Demand for a copy of an old dress watch is small next to demand for a Nautilus or a Daytona. Counterfeit factories chase volume. They copy current models.
Four kinds of fake 1518
1. Modern custom builds
A watchmaker takes a stock chronograph, adds a calendar module, and prints a Patek Philippe dial. Case size runs 38 mm to 40 mm, above the 35 mm of the original. Prices run from about $1,000 to $10,000.
2. Franken watches
A franken watch mixes real and fake parts. Examples: a genuine 1940s gold case with a reprinted dial, or a real movement in a recut case. These are the hardest to spot because part of the watch is real. Auction houses check case and movement numbers before a sale.
3. Generic copies
These use a Seagull ST19 or a Valjoux 7750, a printed dial, and a mineral or sapphire crystal. The moon phase disc often does not track the 29.5 day lunar month.
4. Photo scams
A seller lists a 1518 at $500. The photos come from an auction catalog. The watch does not exist. Payment goes by wire or crypto. No refund follows.
How to check a 1518
- Measure the case. Real: 35 mm across, without the crown.
- Look at the crystal. Real: acrylic with a slight dome. Most copies use sapphire.
- Read the dial print. The "Patek Philippe & Co." signature sits under 12 o'clock.
- Check the stamp inside the caseback. The reference number 1518 and the case serial appear there.
- Check the movement. The calibre 13-130 carries Patek Philippe stamps and a serial number.
- Ask for the archive record. Patek Philippe holds the production books and can match movement to case.
Prices
In November 2016 a stainless steel 1518 sold at Phillips in Geneva for CHF 11,002,000. Gold examples sell for several hundred thousand dollars. A generic copy costs $150 to $800. Custom builds cost more, and they still are not a 1518.
What is not known
No public list covers every surviving 1518. Patek Philippe keeps the production records. Some watches have no archive match because dials and cases were swapped over 70 years.