Grönefeld One Hertz 1912 – Connoisseurs Take Note

Regular readers of The Watch Lounge would no doubt be familiar with the brilliance of the Dutch Master watch-making brothers Tim and Bart Grönefeld (if not, read about them here, here and here). Famed for their exceptional GTM-06 Tourbillon Minute Repeater (the most complicated wristwatch ever created in the Netherlands) the brothers also successfully launched the Grönefeld Boutique in Holland late last year, featuring the likes of Speake-Marin, Sarpaneva and Kees Engelbarts. Now it gives us great pleasure to share their newest creation with you, the Grönefeld One Hertz 1912.
Consistently exceeding expectations
As we have come to expect from such accomplished craftsmen the 1912 is as brilliant as it is unassuming. Classic good looks belie just how complicated this timepiece is, making it exceptionally attractive to true connoisseurs of Haute Horology.
Presented in a 43mm stainless steel case complete with polished bezel and center band and hand-finished straight graining, the resplendent dial displays an hour and minutes sub-dial, a seconds sub-dial, a power reserve indicator and a setting and winding indicator (more on that later). Just looking at this piece one can’t help but be drawn in by its subdued aesthetic beauty, which to the untrained eye would seem to be the main feature of this piece, yet it has so much more than that to offer.
You see, this timepiece is the first and only mechanical wristwatch with independent deadbeat seconds ever produced.
What does that mean exactly?
Well take a second to look down at the superb timepiece on your wrist right now. Chances are that if you are reading this it is of the mechanical variety, be it manual wound or automatic. Now, if you are fortunate enough to have a seconds hand, you will notice that it sweeps through its 60-second journey around the dial.
The seconds hand on the One Hertz 1912, however, does not sweep. It ticks.

Yes, we know what you’re thinking, why would you want it to tick, isn’t that the hallmark of a cheap quartz watch? Ordinarily, yes. In this case, however, it is a celebration of mechanical complexity and ingenuity. You see the driving force behind the concept of dead beat seconds is accuracy. From the wearer’s point of view it is far easier to precisely track the passing of seconds using this sort of display than the common sweeping seconds hand.
So why is this such an achievement?
Well consider this, in order for the seconds hand to be as accurate as possible the supply of power has to be consistently delivered. Therefore, the friction of the mechanism has to be absolutely minimal so it does not interfere with the escapement. To overcome this challenge, the brothers developed a dead beat seconds mechanism that is driven from its own secondary gear train with its own power supply. This means then that the seconds are driven from one mainspring barrel and the hours and minutes from another.
What makes it even more special, however, is that the two mainspring barrels are wound simultaneously from the same crown, meaning that there is no need for secondary crowns or additional winding. As a finishing touch the 1912 also features a highly innovative “push to set, push to wind” function, with the selected mode selected indicated on the dial at 3 o’clock. A power reserve indicator above the deadbeat seconds dial monitors the life-cycle of the 60-hour power supply.
Presented on a hand-sewn, matte black alligator leather strap the 1912 One Hertz will be available in a highly limited production of just 12 pieces.
The Final Word
It really is hard not to be impressed by the outstanding craftsmanship and mechanical accomplishments of Tim and Bart Grönefeld. In our opinion this is what true watch-making is all about. Elegant, refined pieces designed to last lifetimes that have no need to broadcast their exemplary technical credentials. This is a piece that will most certainly appeal to collectors, who undoubtedly will take great pleasure in the knowledge that to most people this is just another timepiece, albeit a rather attractive one.
For the lucky few however, the connection will be personal, an intimate understanding of a most brilliant yet unassuming timepiece.
For more information check out their official website: www.gronefeld.nl/








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