Gronefeld One Hertz Platinum with Dead-Beat Seconds Other countries

Gronefeld One Hertz Platinum with Dead-Beat Seconds

First presented a little more than a year ago during the Baselworld 2011 show, the Gronefeld One Hertz watch from the Dutch watchmakers Tim and Bart Grönefeld has probably proved quite popular if the adventurous brothers have finally decided to present an ultra-expensive, ultra-limited edition of the piece. Called Gronefeld One Hertz Platinum, the watch features the same functions and exactly the same dial layout as the original, but has its massive body crafted from, yes, solid platinum.




As we have already mentioned a year ago, the main selling point of this timekeeper not only its reserved, easy to read design, but also its independent dead-beat seconds mechanism.

In two words, the subsidiary seconds hand circles the dial not in a seemingly ‘sweeping’ motion, but in giant leaps at an interval of precisely one second.

That’s why the watch is called One Hertz.

Gronefeld One Hertz Platinum hand-wound wrist watch

Or maybe it isn’t, since, as far as I remember from my physics classes, the name is wrong in the pure meaning of the term, since one Hertz counts not one event per second, but one cycle per second and the subsidiary seconds hand takes whole 60 seconds to complete the whole circle.

There are a number of timekeepers with the same complication over there (including, for example, the sporty Arnold & Son True Beat 88 (Ref. 1TBAP.B01A.C113A) or the gorgeous F.P. Journe Tourbillon Souverain Remontoir d’Egalite avec Seconde Morte), but the One Hertz is claimed to be the only watch in the world that uses a separate gear train, as well as a separate spring barrel to power the dead beat complication.

Comprising 285 parts, the in-house Caliber G-02 hand-wound movement is quite large measuring 35 millimeters in diameter and almost 9.5 millimeters in height. According to official specification, the dead seconds mechanism includes a “cam with 30 teeth on the going gear train on the second’s wheel, escape wheel on the seconds wheel of the independent gear train, double lever with jewelled pallets”.

Beating at a frequency of 21,600 vibrations per hour and sporting a pair of spring barrels, the movement is good for as long as 72 hours.

Gronefeld One Hertz Platinum hand-wound wrist watch (sapphire case back)

To make winding the piece easier, the watch was equipped with an ergonomically shaped winding crown and even sports a bespoke “Setting/Winding” indicator between two and three o’clock, which makes it easier to choose the function you need to address.

As I have already noted, the only thing that differs the new watch from the original job from the last year is the material of its case.

The rest is still the same: the body of the Gronefeld One Hertz Platinum measures 43 mm in diameter and is around 12.5 mm thick. Its dial is protected from dust and moist with a domed sapphire crystal with antireflective coating on both sides and the laconically decorated movement is also clearly visible through a large sapphire crystal that covers the back of the watch.

The price, as usual, must be completely overwhelming.

By the way, here is a short video that gives you the idea how the G-02 movement actually works:

See also: A. Lange & Sohne Datograph AUF/AB (Power Reserve)

Photos: Grönefeld Watches




Gronefeld One Hertz Platinum hand-wound watch specification

Price: €79,500 (MSRP)
Movement: Manual, Caliber G-02, 35 mm x 9.40 mm, 285 parts, two barrels and two independent gear trains, in-house, Made in Netherlands
Number of jewels: 39, set in gold chatons
Movement frequency: 21,600 vph
Power reserve: 72 hours
Movement decoration: Rhodium plated, micro-blasted, relief engraved
Functions: Hours, minutes, dead beat seconds, power reserve
Case material: Platinum
Bezel material: Matches case
Crown material: Matches case
Case shape: Round
Bezel shape: Round
Case size: 43.00 mm
Case height: 12.50 mm
Lug width: No data
Dial: Blue, off-centered sub-dials
Numerals: None
Hour markers: None
Hands: No data
Water resistance: 30 meters
Strap: Black leather
Crystal: Sapphire, antireflective on both sides, domed
Case back: Sapphire, antireflective coating on the inner side


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