Monochrome Watches
An online magazine dedicated to fine watches

Fonderie 47 Inversion Principle – From Deadly Weapons to Stunning Timepieces

| By Frank Geelen | 4 min read |

A central Three-Minute Flying Tourbillion, Instantaneous Jumping Hours with Quick-Set Pusher, 240 degrees Retrograde Minutes, Lateral and Back Power Reserve Indicators. And all that in an 18-carat white or red gold case with a small piece of an AK-47 assault riffle, with serial number ’56-3701F42′. Kidding? No kidding! 

The piece of metal, originating from a real AK-47 assault riffle, comes with a story. Fonderie 47’s founder, Peter Thum, has a long history as a social entrepreneur and continues this with Fonderie 47 and their first timepiece. The name, Fonderie 47, stands for the melting and casting of the iron coming from AK-47 assault riffles and profits from selling these watches will be used to destroy and eliminate weapons in Africa.

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Fonderie 47 was founded in 2009 by Peter Thum with the goal of reducing the number of destabilizing assault weapons in Africa. Thum realized the enormous problem these weapons created, having met boys and young men armed with assault rifles, and the victims of these weapons, while developing clean water projects in east Africa. There are millions of assault weapons in Africa, costing less then 70% of the ‘normal’ street value.

Thum decided to transform these implements of devastation into something as removed from them and as positive as possible, i.e. exclusive objects that would inspire change and fund the destruction of weapons. The mission to create a high-end mechanical watch incorporating metal from a destroyed AK47 began even before Fonderie 47 was founded, because it quickly became clear that the development and production of a completely original complicated haute horlogerie timepiece would take many years.

Fonderie 47 has also worked with some of the world’s best designers and jewelers to create artistic pieces made from AK47 steel, precious metals and jewels. To this date, over 30,000 assault riffles have been destroyed!

OK, back to the main topic, being the complicated timepiece called Inversion Principle, that was designed by Adrian Glessing and developed and produced by David Candaux/Du Val Des Bois exclusively for Fonderie 47. And yes, it includes a piece of the AK-47, as a black plate on the ratchet wheel. Trough the display back, a beautiful sunray guilloche pattern, radiating out from the ratchet wheel (with a dark plate of steel from a destroyed AK47), is visible. Serial number ’56-3701F42′, of the destroyed weapon the metal is from, is hand engraved in the main plate, beside the ratchet wheel.

The six days of power reserve are indicated both in the case’s side band, and on the back side of the movement. The quick-set hour adjustment is operated through the crown pusher.

The Inversion Principle is available as a limited edition of 20 pieces, 10 in white gold and 10 in red gold, and comes at a price of $ 350,000 USD. That’s a serious price tag, but besides helping Fonderie 47 to reduce the number of assault riffles in Africa, you get a very complicated timepiece. It features a three-minute central flying tourbillon, an instantaneous jumping hours indicator and a retrograde minute indicator that makes a 240 degrees arch over the dial’s lower end.


Attached to the three-minute flying tourbillon, are three seconds hands, that indicate the seconds on the upper section of the dial. Since the tourbillon rotates once every three minutes, every seconds hand will indicate one full minute and than be replaced by the next seconds hand to indicate the seconds of the following minute. At the top, at 12 o’clock, is the jumping hour indicated and visible through an aperture.

Specifications – Fonderie 47 Inversion Principle

Case: 18k white gold or 18k red gold,  42mm x 14.6mm, sapphire crystal traversed by embedded gold bezel bridge framing tourbillon cage, lateral sapphire window in case band for power reserve indicator

Movement Caliber F47-001:

  • Regulator: Central three-minute flying tourbillon
  • Tourbillon cage: gold counter weight and curved to follow sapphire crystal
  • Jumping hour: thin mechanism (patented)
  • Retrograde seconds: mechanism with light aluminum arm and precision regulator
  • Power reserve: six days
  • Balance frequency: 18,000bph (2.5Hz)
  • Jewels: 38
  • Balance spring: Breguet overcoil and distinctive balance spring stud
  • Finishing: Sun ray guilloche; hand engraving; hand polished bevels; heat-blued screws and power reserve indicator on back.

More information through the Fonderie 47 website.

This article is written by Frank Geelen, executive editor for Monochrome Watches.

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