One Hertz


Information from the official Grönefeld website:

ONE HERTZ / TECHNIEK NOCTURNE Part of a limited edition of 30 pieces in grade 5 titanium

The One Hertz Techniek is the world’s only series wristwatch with independent dead seconds and features a stunning, open-work dial that showcases the intricate upper mechanics of Grönefeld’s own proprietary movement, the calibre G-02.

With the One Hertz, Bart and Tim Grönefeld have resurrected the long-neglected complication of dead seconds – where the second hand advances in full steps of one second instead of the usual smooth sweeping action of mechanical seconds – and re-positioned it on the pedestal of high precision.

The Grönefeld One Hertz is unique among wristwatches in that its dead seconds are powered by a secondary gear train, independent of the gear train for the hour and minute indications.

While the One Hertz Techniek’s dial is dominated by the large dead seconds chapter ring in sapphire, the other indications, bridges and Grönefeld logo are crafted in stainless steel, which is relief engraved, bevelled and finished completely by hand.

The open dial is framed by a gleaming high-tech Grade 5 titanium case available in two versions: natural polished and brushed titanium or black DLC – when the timepiece becomes the One Hertz Techniek Nocturne.

Both versions feature the Grönefeld’s own ergonomic winding and setting mechanism, selected by simply pushing the crown in, rather than pulling it out.

The One Hertz Techniek is a limited edition of 30 pieces in Grade 5 titanium, with either a natural finish – One Hertz Techniek – or black DLC coated – One Hertz Techniek Nocturne.

grönefeld-one-hertz-002 grönefeld-one-hertz-003 grönefeld-one-hertz-004 grönefeld-one-hertz-005Technical info:

  • Calibre G-02
  • Mechanical hand winding, independent dead seconds, power reserve indicator and setting mechanism indicator.
  • Dimensions 34mm x 9.5 mm
  • No. of parts 285
  • No. of jewels 39 jewels set in gold chatons
  • Power reserve 72 hours
  • Barrels 2 barrels, one for the going gear train and one for the independent dead seconds mechanism. Both barrels are wound at the same speed and in the same direction
  • Balance wheel 9.12 mm free sprung variable inertia balance wheel Balance frequency: 21’600 bph / 3Hz
  • Balance spring Phillips terminal overcoil curve, triangle-style stud
  • Escapements Swiss lever escapement and unique dead seconds escapement
  • Mainplate Hand frosted and spotted black rhodium plated nickel silver
  • Bridges Stainless steel hand bevelled, micro-blasted, circular grain on the top, relief engraved on micro blasted surface
  • Gearing 2 independent gear trains each with their own energy sources (2 barrels)
  • Dead seconds mechanism Independent mechanism, cam with 30 teeth on the going gear train on the fourth wheel, escape wheel on the fourth wheel of the independent gear train, unique double lever with 4 jewelled pallets
  • Winding-Setting mechanism Push function crown for winding or setting
  • Power reserve mechanism Classic Breguet style by means of a cone moving up and down on the threaded barrel arbour
Case and dial
  • Case material Grade 5 titanium with either a natural polished and brushed finish (One Hertz Techniek) or black DLC coated (One Hertz Techniek Nocturne)
  • Engraving “Titanium”, “Limited 30 pieces” and the serial number
  • Screws Stainless steel security screws
  • Case dimensions 43 mm x 12.5 mm
  • Sapphire crystals Top domed with antireflective treatment both sides; flat display back with antireflective treatment on both sides
  • Water resistance 3atm/30m/100 feet
  • Crown Titanium, black DLC coated with engraved “G” logo and push to set/wind function
  • Dial Stainless steel open dial. Relief engraved, bevelled and finished by hand
  • Hands Hours and minutes, large counter-poised seconds, power-reserve and setting-winding
  • Strap and buckle Hand-sewn matte black, alligator leather with steel tang buckle black DLC coated (Nocturne), Grönefeld logo