Introduced in 2010, the Grönefeld One Hertz was the world’s first series wristwatch with independent dead seconds. Inspired from its success, the One Hertz Dune Red Gold (2011), One Hertz Platinum and One Hertz Titanium (2012) editions were added. This year the collection welcomes a new model in a 43mm red gold case and features a beautiful solid silver dial and entirely in-house developed movement with stainless steel bridges and exceptional fine finishing.
The solid silver dial is dominated by the over-sized dead seconds, and elegantly shaped blued-steel hour and minute hands make for easy reading of the time in the sub dial at 2 o’clock. The hour/minute sub dial is nicely balanced on either side by a power reserve indicator at 11 o’clock and a winding-setting (W-S) function indicator at 3 o’clock.
Winding and setting are selected by pushing the crown in, instead of pulling it out – a very ergonomic system – and the winding-setting indicator provides a neat visual signal of the mode selected. What’s more, the counter-poised seconds hand ‘hacks’ – i.e. stops – when ‘setting’ is selected, to enable maximum precision when setting the time.
The dial is crafted out of solid sterling silver then blasted with brass particles to attain a frosted finish with a very slight sparkle. A thin layer of transparent lacquer is then applied to prevent tarnishing. The soft sheen contrasts superbly with the flamed-blued hands, making for excellent legibility.
The graceful arcs and curves of the displays are complemented by the three-dimensionality of the multi-layered dial. The ensemble is beautifully framed by the highly-polished red gold case and bezel.
All applied dial elements, including the dead seconds chapter ring, are rhodium plated with circular graining and beveled edges. The bevels are polished with diamond paste to a brilliant gloss, creating scintillating reflections of light echoing the high-end finishing of the stainless steel movement bridges visible through the display back.
Features and indications
Independent dead seconds – large dial at 7 o’clock
Hour and minutes – subdial at 2 o’clock
Power reserve indicator at 12 o’clock of seconds ring
Innovative Winding-Setting mechanism Winding-Setting indicator at 3 o’clock
Solid silver dial
In-house calibre G-02
Case and dial
Case:5N red gold case; sapphire crystal on the front is slightly domed with anti-reflective treatment on both sides; sapphire crystal on the back is flat with anti-reflection treatment on the inside; engraving of serial number and model; 8 security screws
Number of case components: 68
Case dimensions: Diameter: 43 mm; thickness: 12.5 mm
Water resistance: 3atm/30 meters/100 feet
Crown: Engraved with “G” logo and push to set/wind function
Dial: in solid silver
Seconds chapter ring:Rhodium plated with circular graining and beveled edges
Hand-sewn, alligator leather with tang buckle engraved with the Grönefeld logo
Calibre G-02: Mechanical hand-wound movement; independent dead seconds
Movement dimensions: Diameter 15 1/4’’’ 34 mm; thickness: 9.5 mm
Number of components: 285 in the whole movement
Number of jewels: 39 jewels 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: Free sprung variable inertia balance wheel (9.12 mm diameter)
Frequency: 21’600 vph
Balance spring: Phillips terminal overcoil curve; triangle-style stud
Escapement: Swiss lever escapement
Mainplate: Spotted and snailed rhodium plated nickel silver
Bridges: Hand bevelled; stainless steel X46 Cr13 Micro-blasted centre; circular grain on the top; relief engraved in the micro blasted surface
Gearing: Two gear trains with their own energy sources (2 barrels)
Dead seconds: Independent mechanism; cam with 30 teeth on the fourth wheel of the going geartrain; special escape wheel on the fourth wheel of the independent geartrain; double lever with four jewelled pallets
Winding-setting: Crown with push function to choose between winding or setting; hacking seconds
Power reserve: Classic Breguet mechanism by means of a cone moving up and down on the threaded barrel arbour