Grönefeld 1941 Grönograaf

Bart and Tim Grönefeld, the award-winning Horological Brothers, present their first chronograph watch. Named 1941 Grönograaf, this classic chronograph incorporates several ingenious details.

Grönefeld 1941 Grönograaf

The 1941 Grönograaf is equipped with the manual-winding calibre G-04. Unlike mass-produced cam-actuated chronographs, this timepiece features a classical configuration, namely a column-wheel and lateral coupling.

Grönefeld 1941 Grönograaf

Mechanical chronograph movements are often subject to harsh forces that can sometimes scar hammers and bend hands. To minimize these damages, the 1941 Grönograaf features a ‘soft reset’ mechanism. A centrifugal governor, positioned at 4 o’clock, typically seen on minute repeaters, slows down the reset function, thereby proving kinder to components while delivering a fascinating spectacle in the process. The governor includes two solid gold weights.

Grönefeld 1941 Grönograaf

Depending on the position of the heart-shaped cams for the counter hands, the relevant minutes and seconds hands rotate clockwise or counter clockwise, heightening the sense of mechanical theatre. The 30-minute counter, located at 6 o’clock, features an instantaneous jumping minutes.

The ruby jewelled hammers lessen the impact when returning to zero. The keyless works features a conical winding pinion and crown-wheel, delivering a smooth winding action.

Grönefeld 1941 Grönograaf

The variable inertia balance mitigates positional influence and offers superior rate stability. The Philips terminal overcoil enhances isochronism, effectively causing the balance spring to breathe more concentrically.

The mainplate is embellished with spotting, while the bridges are formed of stainless steel, polished by hand. Moreover, the bridges have micro-blasted centres, circular graining on the top and feature various engravings in relief. The heart-shaped cams, the elongated chronograph bridge, the gold chatons and the screw-heads are embellished with black polishing, performed in the traditional way using diamond paste on a tin plate.

Grönefeld 1941 Grönograaf

The watch features a 40mm diameter Grönefeld 1941 case made of tantalum or stainless steel. The hours and minutes are shown on an off-centre dial with Lancette hands and trapezoidal indexes. The hands are flame-blued steel, while the centres are mirror polished.

Grönefeld 1941 Grönograaf watch stainless steel

The centrifugal governor at 4 o’clock activates when the reset to zero pusher is pressed.  The chronograph 30-minute counter, located at the base of the dial, features a Breguet-style hand. The instantaneous jumping minutes facilitates ease of read-off. A subsidiary seconds display resides at 9 o’clock, and just above it a power reserve indicator  conveys the status of the mainspring.

Grönefeld 1941 Grönograaf

The central chronograph seconds hand subscribes to the classical Breguet-style and converses with a crisply-marked track positioned on the rehaut, proclaiming the elapsed seconds in an intelligible format.

The ‘Premiere Edition’ of the 1941 Grönograaf in tantalum is limited to just 25 pieces. Thereafter, Grönefeld will release 188 pieces in stainless steel.

Technical details

Model: Grönefeld 1941 Grönograaf

Movement
Caliber G-04
Diameter: 32.0 mm
Thickness: 6.15 mm
Number of parts: 408
Power reserve: 53 hours
Number of jewels: 45 jewels, partially set in solid gold chatons
Chronograph: Column wheel, instantaneous jumping minutes and a gentle reset to zero mechanism. Ruby jeweled hammer
Balance wheel: Variable-inertia balance wheel with timing screws (diameter 10 mm)
Frequency: 21,600 vibrations/hour
Balance spring: Free sprung with Phillips terminal over coil curve with Geneva style stud
Escapement: Jeweled Swiss lever
Main Plate: Spotted and ruthenium electroplated brass main plate
Bridges: Stainless steel, bevels polished by hand, micro-blasted center. Circular grain on the top to highlight the bridges shapes and engravings. Relief engraved Grönefeld logo and the number of jewels
Governor: Speed regulator with gold weights for the gentle return to zero

Case
Material: Tantalum or Stainless Steel
Diameter: 40.00 mm
Thickness: 11.30 mm
Crown: Tantalum or steel, engraved with The Horological Brothers logo
Domed sapphire crystal on the front with hard anti-reflective coating on both sides
Flat sapphire crystal on the back with hard antireflective coating on both sides
Water resistance: 3 atmospheres – 30 meters – 100 feet

Dial
Stainless steel base with rhodium plated sub-dials and elements, frosted and satin-grained surfaces
Decentral hours and minutes at 1 o’clock
Subdial for seconds at 9 o’clock
Power Reserve indicator at 11 o’clock
Large central seconds counter
30 minutes counter at 6 o’clock
Governor Visible “return to zero” speed regulator with gold weights at 3 o’clock

Hands
Extended Lancette hands for hours and minutes
Poised Breguet style chronograph hands
Flame-blued steel and mirror polished centers

Strap
Leather 20mm-18mm
Buckle: Pin buckle made in tantalum or steel engraved with Grönefeld. 18mm

Total number of parts
484 parts (Case: 36 Dial/hands: 40 Movement: 408)

Total weight
Tantalum: 108 grams
Stainless Steel: 85 grams

Price
Stainless steel version: € 155,000 (Limited edition of 188 pieces)
Tantalum version: € 165,000 (Limited edition of 25 pieces)

Grönefeld 1941 Remontoire for Only Watch 2019

Grönefeld has created a unique piece of its 1941 Remontoire watch in support of Only Watch charity auction 2019.

Launched in 2016 as a limited edition of 188 movements only this 1941 Remontoire proved to be a huge success for The Horological Brothers Bart and Tim Grönefeld. Getting near to the end of its production they managed to reserve one unique version of this award-winning timepiece in the category men’s watch at the Grand Prix d’Horlogerie de Genève in 2016.

The Grönefeld 1941 Remontoire features an eight seconds constant force mechanism, ensuring the force serving the balance wheel does not wane. From the mainspring being fully wound to the last minute of its power reserve, the force never fluctuates. The result is that the amplitude and rate remain consistent, leading to superior precision.

From the outset, Bart and Tim always envisaged the Grönefeld 1941 Remontoire as a watch intended to appeal to the most discerning of watch collectors. It was therefore imperative that the movement was befitting of such a timepiece, appealing to the exacting requirements of purists.

The stainless-steel bridges replicate the facades of the Dutch houses, termed ‘bell gables’ and reference the homeland of the Horological Brothers, Bart and Tim. The bridges are hand-beveled, evincing a brilliant gleam, while the centres deliver a sublime contrast with their micro-blasted surfaces, adorned with relief engraving.

The movement includes a balance wheel with white gold timing screws and is equipped with a free-sprung over-coil hairspring with triangular stud. Gold chatons stand testament to the no-compromise specification of this movement whilst mirror polished screws feature chamfered rims and slots. Numerous surfaces glisten, courtesy of mirror-polishing which has been patiently executed by time-served hands. The inventory of different surface decorations include snailed, grained, spotted and frosted surfaces.

Measuring 39.5mm in diameter, with a restrained height of 10.5mm, the 1941 case is the epitome of elegance, courtesy of its discreet, graceful lines. The sculpted stainless-steel 1941 case is executed with a specially shaped cutter to create its characteristic hollowed, concave recesses and convex surfaces. In between each additional cutting phase, the case is polished prior to the next stage of milling, ensuring the precisely defined contours of the case are retained. This process proves incredibly time-consuming but the outcome justifies the effort.

The one-off solid silver dial features a very coarsely frosted surface with highly polished hour markers. Augmented with a subtly vintage smoked surfaces it makes it a worthy special Remontoire for Only Watch 2019.

The watch is worn on a genuine ostrich leather strap with orange lining and a stainless-steel pin buckle.

Grönefeld 1941 Decennium Tourbillon

To celebrate the 10th anniversary of their own independent atelier in the Netherlands, Bart and Tim Grönefeld have created the 1941 Decennium Tourbillon, a limited edition of ten timepieces.

The 1941 Decennium Tourbillon features a 1941 case in platinum. The sculpted case is executed using a specially shaped cutter to create the characteristic hollowed, concave recesses and convex surfaces. In between each additional cutting phase, the case is polished prior to the next stage of milling, ensuring the precisely defined contours of the case are retained. This process proves incredibly time-consuming, but the outcome justifies the effort. The platinum 1941 case measures 39.5mm in diameter, with a restrained height of 10.5mm. The watch weighs 118 grams.

Grönefeld 1941 Decennium Tourbillon

Its automatic winding mechanism ensures the mainspring is optimally wound, resulting in less variation in the rate of the movement. The automatic movement is fitted with a 22-carat solid red gold monobloc rotor. The rotor is completely hand finished and turns on a ceramic ball bearing, preventing wear and eliminating the need for lubrication.

Grönefeld 1941 Decennium Tourbillon

The stainless-steel bridges replicate the facades of the Dutch houses, termed ‘bell gables’. They are hand-bevelled, evincing a brilliant gleam. The centres deliver a sublime contrast with their micro-blasted surfaces and are adorned with relief engraving. The cage of the flying tourbillon, a tourbillon without an upper bridge, is made of stainless steel. The Horological Brothers use stainless steel for the cage and the aforementioned bridges because it is not liable to corrosion and, as such, proffers lasting benefits to the owner.

Grönefeld 1941 Decennium Tourbillon

The 5-arm, double spoke gear train wheels exhibit a contemporary character with their circular grained surfaces paying due reverence to fine watchmaking tradition. The movement includes a balance wheel with white gold timing screws and is equipped with a free-sprung over-coil hairspring with triangular stud.

Gold chatons stand testament to the no-compromise specification of this movement. In addition, the mirror polished screws feature chamfered rims and slots. Numerous surfaces gleam, courtesy of the mirror-polishing which has been patiently executed by time-served hands. The inventory of different decorations includes snailed, grained, spotted and frosted surfaces.

Grönefeld 1941 Decennium Tourbillon

The production will be limited to only 10 examples of the Grönefeld 1941 Decennium Tourbillon.

The price of the Decennium Tourbillon in platinum is € 145,000.00 excluding taxes.

Technical details

Model: Grönefeld 1941 Decennium Tourbillon

Movement
Caliber G-07
Diameter: 32.0 mm
Thickness: 5.5 mm
Number of parts: 259 parts
Power reserve: 56 hours
Number of jewels: 30 jewels, partially set in solid gold chatons
Automatic system: Uni-directional winding mechanism
Oscillating mass: Entirely decorated by hand. 22 karat solid gold. Pivoted on a high precision ceramic ball bearing to avoid excessive wear and the need of lubrication
Tourbillon cage: One-minute flying tourbillon cage pivoted on ceramic ball bearing. Single arm upper cage bridge. Lower Cage and upper cage are both fabricated in stainless steel
Balance wheel: Variable-inertia balance wheel with four white gold timing screws (diameter 10 mm)
Frequency: 21.600 vibrations/hour
Balance spring: Free sprung with Phillips terminal over coil curve with triangle hairspring stud
Escapement: Jewelled lateral Swiss lever escapement
Main Plate: Spotted and ruthenium electroplated brass main plate
Bridges: Stainless steel, bevels polished by hand, micro-blasted center, circular grain on the top to highlight the bridges shapes and relief engravings

Indicators
Central hour and minute hands

Case
Material: Platinum Pt950
Diameter: 39.5 mm
Thickness: 10.5 mm
Engraving: Grönefeld, Platinum, Pt950 and serial number
Crown: Platinum Pt950, engraved with The Horological Brothers logo
Domed sapphire crystal on the front with hard anti-reflective coating on both sides
Flat sapphire crystal on the back with hard anti-reflective coating on both sides
Water resistance: 3 atmospheres – 30 meters – 100 feet

Dial
Sterling Silver 925, Matte grey lacquered with highly polished hour-markers and circular sector
Hands: Extended Lancette hands. Flame-blued steel and mirror polished centres.

Strap
Matte black genuine alligator, black stitching and alligator lining
Width: 20mm-18mm
Buckle: Platinum Pt950 engraved with Grönefeld. 18mm

Total weight
118 Grams

Limited edition
10 pieces only

Grönefeld 1941 Principia Automatic

Almost three years after the release of their multiple award winning 1941 Remontoire watch, Bart and Tim Grönefeld reveal their first automatically wound timepiece the “1941 Principia”.

The ‘Philosophiæ Naturalis Principia Mathematica’ often referred to as simply the Principia, is a body of work by Sir Isaac Newton, delivered in three books. Written in Latin, the Principia formulated the laws of motion and universal gravitation. This Newton’s scientific study is the foundation of classical mechanics and it led the Horological Brothers Bart and Tim Grönefeld to select the ‘Principia’ name for their first watch with automatic winding mechanism.

In the sphere of watchmaking, gravity can be a friend or foe. The slightest motion of the wearer’s wrist causes an oscillating weight to rotate under gravity. It is this rotation which imparts energy to the mainspring, obviating the need for the wearer to wind the watch. In this instance, the benefit of gravity is harvested, making the 1941 Principia Automatic ideal for daily wear.

However, gravity can also be problematic, exerting undue influence on the rate keeping of a watch. When a timepiece is held in various positions it can run fast or slow. To mitigate the influence of such positional errors, the Grönefeld 1941 Principia Automatic is fitted with a free-sprung hairspring. This specification detail is superior to a simple index-adjuster, but Grönefeld feel it justifies the additional expense involved.

The Horological Brothers have given much consideration to the dial design, which delivers peerless readability and a handsome aesthetic.

Each version of the 1941 Principia is offered with an array of dials, all crafted in solid sterling silver. The would-be wearer can choose from a cream lacquered dial with roman numerals, a refreshing matt turquoise or light blue dial with polished applied baton hour markers. Alternatively, the company’s rhodium plated or gold plated salmon dials are also available. The cream lacquer dial features the same traditional logotype first used by Bart and Tim’s Grandfather, Johan Grönefeld, back in 1912.

The extended Lancette hour and minute hands are flame-blued and include mirror-polished centres. In the lower portion of the dial is a small seconds display. A flame-blued hand with an elegant counterweight traverses the display with notable poise. At the top of the subdial on the cream lacquer dial, ’60’ is proclaimed in a subtle shade of orange. It is a patriotic reference to Bart and Tim’s country of birth, The Netherlands.

The 1941 Principia is housed in the company’s 1941 case. Named after the year their father Sjef was born, the 1941 case exudes grace from every angle. It is available in red gold, white gold or stainless steel.

The sculpted case is executed using specially shaped cutters to create the characteristic hollowed, concave recesses and convex surfaces. In between each additional cutting phase, the case is polished prior to the next stage of milling, ensuring the precisely defined contours of the case are retained. This process proves incredibly time-consuming, but the outcome justifies the effort.

Each lug is retained with two hidden titanium screws, positioned inside the case. The lugs can be detached for remedial polishing or, should they have been subject to excessive trauma, they can be replaced.

Measuring 39.5mm in diameter, with a restrained height of 10.5mm, the 1941 case is the epitome of elegance, courtesy of its discreet mien.

Apart for the ease of use an automatic movement also ensures the mainspring is optimally wound, resulting in less variation of the amplitude of the balance wheel resulting in better performance.

In normal use, the wearer does not need to operate the crown, mitigating the risk of harm to the crown stem. This Grönefeld Principia automatic watch confers convenience, making it ideal for daily use.

Bart and Tim always wanted the Grönefeld 1941 Principia to appeal to the most discerning watch collectors. It was therefore imperative that the movement was befitting of such a timepiece. The stainless-steel bridges replicate the facades of the Dutch houses, termed ‘bell gables’, once again, referencing the homeland of the Horological Brothers. The bridges are hand-bevelled, evincing a brilliant gleam. The centres deliver a sublime contrast with their micro-blasted surfaces and are adorned with relief engraving.

The 1941 Principia Automatic is fitted with a 22-karat solid red gold monobloc rotor. The eye-catching oscillating weight is extensively decorated by hand and turns on a ceramic ball bearing, preventing wear and eliminating the need for lubrication.

The Grönefeld 5-arm, double spoke gear train wheels exhibit a contemporary character, but their circular grained surfaces pay due reverence to fine watchmaking tradition. Their design, as well as the bevelled escape wheel teeth, prevent the oil dissipating, thereby mitigating wear. The movement includes a balance wheel, with white gold timing screws, and is equipped with a free-sprung hairspring. The escapement is adjusted to heat-cold, isochronism and six positions.

Gold chatons stand testament to the no-compromise specification of this movement. In addition, the mirror polished screws feature chamfered rims and slots. Numerous surfaces gleam, courtesy of the mirror-polishing which has been patiently executed by time-served hands. The inventory of different decorations includes snailed, grained, spotted and frosted surfaces, indulging the desires of purists. With so much beauty harnessed within the Grönefeld 1941 Principia, a sapphire case back has been fitted to confer a spectacular view.

The Grönefeld 1941 Principia, with its self-winding movement, successfully harnesses gravity, making it ideal for daily wear. Furthermore, as this watch demonstrates, the Horological Brothers have overcome the detrimental effects of gravity and delivered a highly precise watch for the delectation of purists.

Not limited by numbers but the production of the Principia is limited by virtue of the time-consuming creation of each movement. Each movement is finished and assembled by hand. To emphasize the manual labour a gold plate, engraved with an individual number, is applied to the movement.

Each Grönefeld 1941 Principia is delivered with a high quality, double axis, watch-winder made by Bernard Favre.

Technical details

Movement
Diameter: 32,0 mm
Thickness: 5,5 mm
Number of parts: 226 parts
Power reserve: 56 hours
Number of jewels: 31 jewels, partially set in solid gold chatons
Automatic system: Uni-directional winding mechanism
For 24 hours of autonomy 633 rotations of the Oscillating mass are required
Oscillating mass: Entirely decorated by hand. 22-karat solid gold. Pivoted on a high precision ceramic ball bearing to avoid excessive wear and the need of lubrication
Balance wheel: Variable-inertia balance wheel with four white gold timing screws (diameter 10 mm)
Frequency: 21.600 vibrations/hour
Balance spring: Free sprung with Phillips terminal over coil curve with triangle hairspring stud
Escapement: Jewelled Swiss lever
Main Plate: Spotted and ruthenium electroplated brass main plate
Bridges: Stainless steel, bevels polished by hand, micro-blasted center, circular grain on the top to highlight the bridges shapes and relief engravings

Displays
Central hours and minutes
Small seconds at 6 o’clock

Case
Red Gold Au750 5N, White Gold Au750/Pd210 (non rhodium plated) or Stainless Steel 916L
Diameter: 39,5 mm
Thickness: 10,5 mm
Water resistance 3 atmospheres – 30 meters – 100 feet
Crown: Red Gold Au750 5N, White Gold Au750/Pd210 (non rhodium plated) or Stainless Steel 916L engraved with logo

Dial
Base material: Solid Sterling Silver 925

Hands
Extended Lancette hands. Flame-blued steel and mirror polished centres
Small poised seconds hand

Strap
A vast variety of leathers and colors are available
Pin buckle made in Red Gold Au750 5N, White Gold Au750/Pd210 (non rhodium plated) or Stainless Steel 916L engraved with Grönefeld

Grönefeld

The name Grönefeld and the art of watchmaking have a family history spanning a hundred years, originating in the ancient town of Oldenzaal in the Netherlands. There, in a shop facing the ancient basilica church from 1240, Johan Grönefeld, Bart and Tim’s grandfather, began his career as a watchmaker in 1912, marking the beginning of the highly talented dynasty of Grönefeld watchmakers that continues today.

Bart and Tim Grönefeld

Bart and Tim’s workshop is located in Johan Grönefeld’s original building, representing a continuous, unbroken watchmaking family history that is exceptionally rare to find anywhere in the world today.

Bart and Tim underwent extensive training in Switzerland, and within a relatively short span of time proved themselves adept world specialists in the production of the most coveted and exquisite horological complications of all: the tourbillon and the minute repeater wristwatch.

In 2008, after working anonymously behind the scenes for prestigious Swiss brands, they presented the first watch bearing their own name, the GTM-06 Tourbillon Minute Repeater.

In 2010, Bart and Tim presented their second watch, the One Hertz, the world’s first series wristwatch with independent dead seconds and featuring a completely new movement, the G-02 Calibre. The One Hertz Classic collection has grown to include the One Hertz 1912, One Hertz Dune, One Hertz Ruthenium, One Hertz Titanium and One Hertz Platinum, while the Contemporary collection, launched in 2012, includes the One Hertz Fire and the One Hertz Ice. In 2013, the open-dial One Hertz Techniek was launched.

The One Hertz is a prize-winning timepiece. It was awarded the Innovation prize in the 0024 WatchWorld Watch of the Year contest in 2011 and was voted Watch of the Year in 2011 by members of the influential watch forum Timezone.

In 2014, Bart and Tim presented the  PARALLAX TOURBILLON and in 2016 they launched the 1941 Remontoire watch. In 2018, Grönefeld introduced new versions of the 1941 Remontoire watch and their latest creation, the 1941 Principia Automatic.

Official website: https://www.gronefeld.com

[Page updated on 18 Oct 2018]

Grönefeld 1941 Remontoire – New Versions

The Horological Brothers, Bart and Tim Grönefeld announce bespoke dials and a new case material for their award winning Grönefeld 1941 Remontoire timepiece. Netherlands based Grönefeld brothers have partnered with renowned master watchmaker Kari Voutilainen to realise these new editions of high-end, technical timepieces under 1941 Remontoire line.

Grönefeld is able to offer a vast choice of coloured and patterned dials. The dials are engine-turned, sometimes referred to as guilloché dials. This process confers each dial with its own unique appearance. To augment the allure of the engine-turned patterns, another even more exclusive technique can be applied, enamelling. The colourful and transparent enamel is applied to the dial surface to bestow a profound depth and lustre to the guilloché patterns.

The ‘engine turned’ dials are actually made on a century old machine. Every decorative line is made at very slow speed by deft hand and the skilful precision of a well-trained eye. It actually takes a few days of painstaking and patient effort to produce just one guilloché dial.

Because enamel is glass, not paint, it does not fade under ultraviolet light and will keep its lustre for years, decades or even centuries to come. Specialist Inès Hamaguchi is responsible for the delicate enamelling of the Grönefeld dials.

Besides the existing versions in 18-carat red and white gold, the 1941 Remontoire is now also offered in stainless steel. Bart and Tim believe the 1941 Remontoire looks spectacular in a stainless steel case owing to the combination of the case material and the distinctively arranged, hand decorated, stainless steel bridges.

For this case, the 316L stainless steel alloy has been specially treated to obtain a very fine molecular structure. This treatment results in a brighter colour and glossier finish than a non-treated stainless steel alloy.

A maximum of 25 Remontoire watches in a stainless steel case will be made. These will be offered with the existing collection of dials as well as the new, bespoke engine turned and enamel dials.

Technical details
Model: Grönefeld 1941 Remontoire

Movement
Hand-wound Mechanical Movement, Calibre G-05
8 Seconds Remontoire Mechanism
Diameter: 32,0 mm
Thickness: 5,5 mm
Number of parts: 258 parts
Number of jewels: 36 jewels, partially set in solid gold chatons
Power reserve: 36 hours with constant force (stop system)
Remontoire: To optimize time keeping a small hairspring is wound every 8 seconds to guarantee a constant force for the escapement. A complex satellite gearing mechanism with hypocycloidal gears, twin ball bearings, pinions and jewelled levers, achieve this.
Balance wheel: Variable-inertia balance wheel with four white gold timing screws (diameter 10 mm)
Frequency: 21.600 vibrations/hour
Balance spring: Free sprung with Phillips terminal over coil curve with triangle hairspring stud
Escapement: Jewelled Swiss lever
Main Plate: Spotted and ruthenium electroplated brass main plate
Bridges: Stainless steel, bevels polished by hand, micro-blasted centre; Circular grain on the top to highlight the bridges shapes and engravings; Relief engraved Grönefeld logo, number of jewels and eight seconds remontoire
Hacking seconds: In setting mode the hacking seconds mechanism will be activated

Displays  
Central Hours and Minutes
Small Seconds at 6 o’clock
Governor speed regulator at 9 o’clock

Case
Stainless Steel 916L, White Gold Au750/Pd150 (Non Rhodium plated) or Red Gold Au750 5N
Domed sapphire crystal on the front with hard antireflective coating on both sides
Flat sapphire crystal on the back with hard antireflective coating on both sides
Engraving: Grönefeld and the individual number
8 gold or stainless steel security screws
Diameter: 39,5 mm
Thickness: 10,5 mm
Water resistance: 3 atmospheres – 30 meters – 100 feet
Crown: Stainless steel, White gold Au750/Pd150 (Non Rhodium plated) or Red gold Au750 5N engraved    with logo

Dial 
Sterling Silver 925, Guilloché dials are handmade.
Hands: Extended Lancette hands. Flame-blued steel and mirror polished centres. Small poised seconds    hand

Strap   
Hand-sewn ostrich leather with Stainless steel, White Gold Au750/Pd150 or Red Gold Au750 5N buckle Engraved with Grönefeld logo

Grönefeld 1941 Remontoire

Grönefeld, the luxury watch atelier established by Netherlands based Horological Brothers Bart and Tim Grönefeld, presents it latest creation, the 1941 Remontoire.

Unveiled at Baselworld 2016, the Grönefeld 1941 Remontoire watch features an eight seconds constant force mechanism, ensuring the force serving the balance wheel does not wane. From the mainspring being fully wound to the last minute of the 35 hours of power reserve, when the stop works intervenes, the force never fluctuates. The result is that the amplitude and rate remain consistent, leading to superior precision.

For this new creation, Bart and Tim took inspiration from the Saint Plechelmus church clock movement, close to the location of the company’s workshops. This movement has always played an important part in the history of Grönefeld. Johan Grönefeld, the brother’s grandfather, was responsible for maintaining the church clock. When Johan passed away, this responsibility passed to their father, Sjef.

The church clock, created in 1913 by Royal Eijsbouts in the village of Asten, The Netherlands is equipped with a remontoire mechanism. The rationale for the remontoire being used in the church clock was the clock’s display was positioned much higher than the movement, necessitating significant force. However, the magnitude of such force would prove too great for a conventional escapement, hence a remontoire, or constant force mechanism, was fitted. Moreover, the minute hand was calibrated to jump every 30 seconds, breaking any ice which may have formed in cold weather and, in so doing, preventing the clock hands from freezing.

To coincide with the release of the Grönefeld 1941 Remontoire, Bart and Tim are also revealing for the first time, the new 1941 case. This case design, named after the year their father was born, harnesses much craftsmanship and is intended to recognise the positive influence Sjef has had on their lives.

The sculpted case is executed with a specially shaped cutter to create its characteristic hollowed, concave recesses and convex surfaces. In between each additional cutting phase, the case is polished prior to the next stage of milling, ensuring the precisely defined contours of the case are retained. This process proves incredibly time-consuming but the outcome justifies the effort.

The lugs are retained with two hidden titanium screws, positioned inside the case. The lugs can be detached for remedial polishing or, should they have been subject to excessive trauma, they can be replaced.

For the first time, Grönefeld offers the new 1941 case in 18-carat white gold, alloyed with Palladium 150. This form of gold alloy is costlier but obviates the need for rhodium plating, hence its surface will not wear out. Alternatively, a 5N red gold case option is available.

Measuring 39.5mm in diameter, with a restrained height of 10.5mm, the 1941 case is the epitome of elegance, courtesy of its discreet, graceful lines.

The solid Sterling Silver dial features frosted and satin-grained surfaces, augmented with subtly polished edges. It employs three dial feet rather than the customary two, ensuring a very stable, solid union with the movement beneath.

The extended Lancette hour and minute hands are flame-blued steel and include hand polished centres. The hour circle sits higher than the central dial area, delightfully playing with depths to eye-catching affect.

Each hour is denoted with an applied index which is faceted and diamond cut. The tapering point of each index guides the eyes towards the central area of the dial, aiding interpretation of the highly lucid display of hours and minutes.

In the lower portion of the dial is a small seconds display, this again masterfully plays with depths to deliver a sumptuous aesthetic appearance. A grained circlet, marked with Arabic numerals, provides a fascinating contradistinction with the adjacent frosted surfaces.

Every change of dial depth is accentuated with a highly polished bevelled edge, engaging beautifully with ambient light.

The Grönefeld 1941 Remontoire features a governor to regulate the speed of the remontoire mechanism. Positioned at 9 o’clock designed to mitigate shocks to the gear train from the remontoire mechanism stopping. It rotates every eight seconds, adopting a calm tempo and bestowing a sense of calmness.

The dial is signed with “Grönefeld’, ‘Eight Seconds Remontoire’ and ‘Handcrafted”. Indeed, every component is finished by hand to the highest standard.

From the outset, Bart and Tim always envisaged the Grönefeld 1941 Remontoire as a watch intended to appeal to the most discerning of watch collectors. It was therefore imperative that the movement was befitting of such a timepiece, appealing to the exacting requirements of purists.

The stainless steel bridges replicate the facades of the Dutch houses, termed ‘bell gables’ and reference the homeland of the Horological Brothers, Bart and Tim. The bridges are hand-beveled, evincing a brilliant gleam, while the centres deliver a sublime contrast with their micro-blasted surfaces, adorned with relief engraving.

The new 5-arm, double spoke gear train wheels exhibit a contemporary character, but their circular grained surfaces pay due reverence to fine watchmaking tradition. The movement includes a balance wheel with white gold timing screws and is equipped with a free-sprung over-coil hairspring with triangular stud.

Gold chatons stand testament to the no-compromise specification of this movement whilst mirror polished screws feature chamfered rims and slots. Numerous surfaces glisten, courtesy of mirror-polishing which has been patiently executed by time-served hands. The inventory of different surface decorations will sate the desires of any purist and include snailed, grained, spotted and frosted surfaces.

With so much beauty harnessed within the Grönefeld 1941 Remontoire it only seemed appropriate to share the movement with wearers, equipping the timepiece with a sapphire caseback.

The time-consuming creation of each movement means that production will be limited to only 188 Remontoire movements, each with its own unique serial number, offered in a choice of case material and dial variants.

Technical details
Model: Grönefeld 1941 Remontoire
8 Seconds Remontoire Mechanism
Hand-wound Mechanical Movement, Calibre G-05

Movement
Calibre G-05
Diameter:32,0 mm
Thickness:5,5 mm

Number of parts: 258 parts
Number of jewels: 36 jewels, partially set in solid gold chatons
Power reserve: 36 hours with constant force (stop system)
Remontoire: To optimize time keeping a small hairspring is wound every 8 seconds to guarantee a constant force for the escapement. A complex satellite gearing mechanism with hypocycloidal gears, twin ball bearings, pinions and jewelled levers, achieve this.
Balance wheel: Variable-inertia balance wheel with four white gold timing screws (diameter 10 mm)
Frequency: 21.600 vibrations/hour
Balance spring: Free sprung with Phillips terminal over coil curve with triangle hairspring stud
Escapement: Jewelled Swiss lever
Main Plate: Spotted and ruthenium electroplated brass main plate

Bridges   
Stainless steel, bevels polished by hand, micro-blasted centre
Circular grain on the top to highlight the bridges shapes and engravings
Relief engraved Grönefeld logo, number of jewels and eight seconds remontoire

Hacking seconds  
In setting mode the hacking seconds mechanism will be activated

Displays
Central Hours and Minutes
Small Seconds at 6 o’clock
Governor speed regulator at 9 o’clock

Case
White Gold Au750/Pd150 (Non Rhodium plated) or Red Gold Au750 5N
Domed sapphire crystal on the front with hard antireflective coating on both sides
Flat sapphire crystal on the back with hard antireflective coating on both sides
Engraving: Grönefeld and the individual number
8 White gold security screws
Diameter: 39, 5 mm
Thickness: 10,5 mm
Water resistance: 3 atm(30 meters/100 feet)
Crown: White gold Au750/Pd150 (Non Rhodium plated) / Red gold Au750 5N engraved with logo

Dial   
Sterling Silver 925, frosted and satin-grained surfaces

Hands
Extended Lancette hands
Flame-blued steel and mirror polished centres
Small poised seconds hand

Strap 
Hand-sewn ostrich leather with White Gold Au750/Pd150 or Red Gold Au750 5N buckle Engraved with Grönefeld logo

Grönefeld PARALLAX Tourbillon in Platinum

Netherlands based luxury watch atelier Grönefeld presents a unique platinum version of its award winning horological masterpiece, the PARALLAX Tourbillon.

In October 2014, brothers Bart and Tim Grönefeld won the international jury award of the Grand Prix d’Horlogerie de Genève for the Parallax Tourbillon in the tourbillon category.

One of the most coveted horology marvels in the contemporary watch making industry, the Grönefeld Parallax Tourbillon features a “flying” tourbillon with a large central seconds hand, stop seconds, a power reserve- and winding-setting mechanism indicator. The hand finished movement displays sophistication and craftsmanship at the very highest level.

Flying Tourbillon: Well-designed and impeccably executed tourbillons are particularly accurate timekeepers. The flying tourbillon allows full appreciation of the concentric, rhythmic “breathing” of the balance hairspring, while ensuring high precision. Bart and Tim Grönefeld further highlighted the tourbillon by raising it out of the movement and above the dial. As with the immaculately finished movement bridges, the tourbillon cage is crafted in stainless steel. Three days are required just for the hand finishing of the tourbillon components.

Large Central Seconds: The precision of the Parallax Tourbillon is evidenced by the large central seconds hand. Normally a central seconds hand requires a friction spring to prevent small fluttering caused by play in the gear train.

For the Parallax Tourbillon, the Grönefeld brothers developed the movement with an added pinion and wheel so that the energy-sapping friction spring is not required: A feature improving power transfer to the regulator and contributing to the precision and impressive power reserve of 72-hours.

Push -Only Crown and Function Indicator: In addition to the flying tourbillon and friction-spring-free central seconds, the Parallax Tourbillon has yet another innovative feature: rather than pulling the crown to set the time, which has the risk of damaging the fragile crown stem, it is pressed.

An indicator on the dial displays the function selected: “W” for Winding or “S” for time setting. When the time setting function is selected, both tourbillon cage bridge and the central seconds hand automatically return to their respective 12 o’clock positions and stop (or hack) while the time is set.

Stainless Steel Bridges: For this unique piece Bart and Tim Grönefeld made special blackened stainless steel bridges for this unique movement to enhance the contrast. As well as the superior hardness and durability of stainless steel compared to standard brass or nickel, the metal absolutely gleams when polished to a mirror finish. And as stainless steel does not oxidize, the gleaming finish lasts and lasts.

Technical Specifications
Model: Grönefeld Parallax Tourbillon in Platinum

Features and indications
Flying one minute Tourbillon
Hours and minutes
Central seconds
Power reserve and Winding-Setting indicator
Innovative Winding-Setting Mechanism with Hacking Seconds
In-house caliber G-03

Case
Case material: Platinum Pt950.
Engraving: Grönefeld, Unique Piece and Platinum
Case dimensions: 43 mm x 12.5 mm
Sapphire Crystals: Top domed with anti-reflective treatment both sides; flat display back with antireflective treatment on both sides
Water resistance: 3atm/30m/100 feet
Crown: White gold with engraved “G” logo and push to set/wind function

Dial
Solid Sterling Silver 925, Black ruthenium plated frosted surface with orange print.
Hours- Minutes dial, power reserve indicator, setting-winding indicator
Raised seconds dial to minimalize a parallax error
Hands: Polished extended steel Lancette hands
Large counter poised seconds hand

Strap and buckle
Orange thread hand-sewn matte black alligator leather and platinum buckle with engraved Grönefeld logo

Movement
Caliber G-03: Mechanical hand winding, flying one-minute stainless steel tourbillon, power-reserve indicator, hacking seconds and setting mechanism indicator.
Dimensions: 34mm (15 1/4 ’’’) x 9.5 mm
Number of parts: 278
Number of jewels: 27 jewels set in solid gold chatons
Power reserve: 72 hours
Balance wheel: 10 mm free sprung balance wheel Balance frequency: 21’600 vph / 3Hz
Balance spring: Phillips terminal over-coil curve, Geneva-style stud. ELINVAR spring by Nivarox®
Escapement: Straight Swiss lever escapement
Main Plate: Hand spotted rhodium-plated nickel silver
Bridges: Stainless steel and beveled an polished by hand, micro-blasted, circular grain on the top, relief engraved on micro blasted surface
Winding-Setting mechanism: Push function crown for selecting winding or setting
Power reserve mechanism: Classic Breguet style by means of a cone moving up and down on the threaded barrel arbor

Price
€ 160.000,00 Excluding Taxes

Grönefeld – New One Hertz, 18ct Red Gold Case, Silver Dial

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.

Gronefeld – New One Hertz watch with 18ct Red Gold Case, and Silver Dial

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.

Gronefeld – New One Hertz watch with 18ct Red Gold Case, and Silver Dial

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.

Gronefeld – New One Hertz watch with 18ct Red Gold Case, and Silver Dial

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.

Technical details

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

Strap
Hand-sewn, alligator leather with tang buckle engraved with the Grönefeld logo

Movement
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

GRÖNEFELD PARALLAX TOURBILLON

Grönefeld is a Netherlands based independent luxury watch manufacture that debuted in 2008 with an exceptional Tourbillon Minute Repeater wristwatch (GTM 06). This young watch manufacture has been specialised in the production of prestigious timepieces such as their award-winning One Hertz model (introduced in 2010) which houses their first in-house developed calibre.

This year, its founders Bart and Tim Grönefeld are introducing a highly sophisticated tourbillon timepiece. The Grönefeld Parallax Tourbillon, the latest offer from the prestigious watch making firm will be displayed at Baselworld 2014.

GRÖNEFELD PARALLAX TOURBILLON watch

The Grönefeld Parallax Tourbillon features a “flying” tourbillon with a large central seconds hand, stop seconds, a power reserve- and winding-setting mechanism indicator. The in-house movement displays sophistication and craftsmanship at the very highest level.

GRONEFELD PARALLAX TOURBILLON watch

The flying tourbillon allows full appreciation of the concentric, rhythmic “breathing” of the balance hairspring, while ensuring high precision. Bart and Tim Grönefeld further highlighted the tourbillon by raising it out of the movement and above the dial.

GRÖNEFELD PARALLAX TOURBILLON

As with the immaculately finished movement bridges, the tourbillon cage is crafted in stainless steel. Three days are required just for the hand finishing of the tourbillon components.

The large central seconds hand evidences the precision of the Parallax Tourbillon. Normally a central seconds hand requires a friction spring to prevent small fluttering caused by play in the gear train.

GRÖNEFELD PARALLAX TOURBILLON watch movement

For the Parallax Tourbillon, the Grönefeld brothers developed the movement with an added pinion and wheel so that the energy-sapping friction spring is not required. This feature improves power transfer to the regulator and contributing to the impressive power-72-hour power reserve.

GRONEFELD PARALLAX TOURBILLON watch movement

Parallax

The name “Parallax” is derived from the precision of the readability of the central seconds hand. Parallax is defined as the apparent change in position of an object when the observer changes his own position. To minimize the possibility of error due to parallax when viewing the seconds hand from an angle, the hand is exceptionally close to the outer chapter ring with the seconds indexes. In a neat addition, the one-armed balance wheel bridge always runs parallel to the central seconds hand.

Push-only crown and function indicator

In addition to the flying tourbillon and friction-spring-free central seconds, the Parallax Tourbillon has yet another innovative feature: rather than pulling the crown to set the time, which has the risk of damaging the fragile crown stem, it is pressed. An indicator on the dial displays the function selected: “W” for Winding or “S” for time setting. When the time setting function is selected, both tourbillon cage-bridge and the central seconds hand automatically return to their respective 12 o’clock positions and stop (or hack) while the time is set.

The ability to set the time to the exact second makes the Parallax Tourbillon potentially more accurate then the vast majority of tourbillons on the market today. Once the time is set and the function set to winding by a simple press of the crown, both the seconds hand and tourbillon cage start running simultaneously and in parallel.

GRÖNEFELD PARALLAX TOURBILLON watch in red gold

Solid silver dial

The solid-silver dial of the Parallax Tourbillon is composed of seven individual components. The polished beveled edges of the segments mirror those of the stainless steel movement bridges, which are visible through the display back. The bevels are polished with diamond paste to a brilliant gloss and create scintillating reflections of light. Flame-blued steel hands for the hours, minutes and seconds ensure that the time is as legible as it is precise.

Stainless steel bridges

Bart and Tim Grönefeld only use stainless steel bridges for their movements. As well as the superior hardness and durability of stainless steel compared to the more generally used steel and brass, the metal absolutely gleams when polished to a mirror finish.

And as stainless steel does not oxidize, the gleaming finish lasts and lasts. However, achieving superlative finishes in stainless steel is no easy task: polishing the hard metal takes a master watchmaker up to four times longer than more commonly used brass.

GRÖNEFELD PARALLAX TOURBILLON watch red gold model

The Parallax Tourbillon is available in a red gold or stainless steel case 43mm case. Ensuring the exclusivity of this exceptional timepiece, the red gold model is a limited edition of 28 pieces and the “1912” stainless steel model is a limited edition of just 12 pieces.

GRONEFELD PARALLAX TOURBILLON watch

Technical details

Collection: Parallax Tourbillon

Editions
The Parallax 1912 is a limited edition of 12 pieces in stainless steel
The Parallax RG is a limited edition of 28 pieces in Au750 red Gold 5N

Features and indications
Flying one minute Tourbillon
Hours and minutes
Central seconds
Power reserve and Winding-Setting indicator
Innovative Winding-Setting Mechanism with Hacking Seconds
In-house caliber G-03

Case
Stainless Steel 316L(4335) or Au750 red gold
Engraving 1912: 1912 and individual number in relief. Limited 12 pieces. Stainless steel security screws
Engraving RG: Parallax and individual number in relief. Limited 28 pieces. Serial number. Gold security screws
Case dimensions: 43 mm x 12.5 mm
Sapphire crystals: Top domed with anti-reflective treatment both sides; flat display back with antireflective treatment on both sides
Water resistance: 3atm/30m/100 feet
Crown: Steel or gold with engraved “G” logo and push to set/wind function

Dial
Solid Sterling Silver 925, Frosted surface with diamond cut bevels
Hours- Minutes dial, power reserve indicator, setting-winding indicator
Raised seconds dial to minimalize a parallax error
Hands: Flame-blued steel extended Lancette hands and hand polished centers. Large counter poised seconds hand

Strap and buckle
Hand-sewn matte blue or brown alligator leather and steel or gold tang buckle with engraved Grönefeld logo

Movement
Caliber G-03: Mechanical hand winding, flying one-minute stainless steel tourbillon, power-reserve indicator, hacking seconds and setting mechanism indicator.
Dimensions: 34mm (15 1/4 ’’’) x 9.5 mm
Number of parts: 278
Number of jewels: 27 jewels set in solid gold chatons
Power reserve: 72 hours
Balance wheel: 10 mm free sprung balance wheel Balance frequency: 21’600 vph / 3Hz
Balance spring: Phillips terminal over-coil curve, Geneva-style stud. ELINVAR spring by Nivarox®
Escapement: Straight Swiss lever escapement
Main Plate: Hand spotted rhodium-plated nickel silver
Bridges: Stainless steel and beveled an polished by hand, micro-blasted, circular grain on the top, relief engraved on micro blasted surface
Winding-Setting mechanism: Push function crown for selecting winding or setting
Power reserve mechanism: Classic Breguet style by means of a cone moving up and down on the threaded barrel arbor

Grönefeld One Hertz Hertz Classic Collection

Introduced in 2010 by Dutch watchmakers Bart and Tim Grönefeld, the One Hertz is the world’s first and only series wristwatch with independent dead seconds.

The One Hertz is a prize-winning timepiece. It was awarded the Innovation prize in the 0024 WatchWorld Watch of the Year contest in 2011 and was voted Watch of the Year in 2011 by members of the influential watch forum Timezone. The One Hertz Hertz Classic features five exclusive limited editions: Platinum, Titanium, Ruthenium, Dune and 1912.

Grönefeld One Hertz Hertz Classic Collection

The One Hertz Hertz Classic collection features five exclusive limited editions:

The One Hertz Platinum: The One Hertz Platinum features an exclusive platinum case and cool blue dial. The ensemble of indications is all the more striking thanks to the sophisticated blue dial background which perfectly complements the regal tones of the precious metal platinum case.  Limited edition of 12 pieces.

Grönefeld One Hertz Hertz Classic watch platinum
One Hertz Platinum

The One Hertz Titanium: The One Hertz Titanium features a high-tech, polished and brushed titanium case as well as a fresh white micro-guilloched dial.  Limited edition of 30 pieces in polished and brushed grade 5 titanium.

Grönefeld One Hertz Hertz Classic watch titanium
One Hertz Titanium

The One Hertz Ruthenium: The One Hertz Ruthenium features a titanium case and sleek, dark ruthenium dial. Limited edition of 30 pieces in polished and brushed grade 5 titanium with ruthenium dial.

Grönefeld One Hertz Hertz Classic watch ruthenium
One Hertz Ruthenium

The One Hertz Dune: The One Hertz Dune features a sophisticated red gold case and stylish brown dial. Limited edition of 20 pieces in red gold.

Grönefeld One Hertz Hertz Classic watch dune
One Hertz Dune

The One Hertz 1912: The One Hertz 1912 features a stainless steel case and stylish monochromatic grey dial. It is so named because 1912 was the year Bart and Tim’s grandfather Johan Grönefeld qualified as a watchmaker. Limited edition of 12 pieces in stainless steel.

Technical details

Collection: One Hertz Classic

Models
One Hertz Platinum – limited edition of 12 pieces featuring platinum case
One Hertz Titanium – limited edition of 30 pieces featuring polished and brushed grade 5 titanium case
One Hertz Ruthenium – limited edition of 30 pieces featuring polished and brushed grade 5 titanium case with ruthenium dial
One Hertz Dune – limited edition of 20 pieces featuring red gold case and security screws
One Hertz 1912 – limited edition of 12 pieces featuring stainless steel case (Now sold out)

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
In-house calibre G-02

Case and dial
Case: Polished bezel and centre band with hand-finished straight graining; 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
Seconds chapter ring: Made of sapphire
Strap: Hand-sewn, alligator leather with tang buckle engraved with the Grönefeld logo

Movement
Calibre G-02: Mechanical hand-wound movement; independent dead seconds
Movement dimensions: Diameter 15 1/4’’’ 9.5 mm; thickness: 34 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
Power reserve: Classic Breguet mechanism by means of a cone moving up and down on the threaded barrel arbour

Grönefeld “One Hertz Techniek” Limited Edition

After the successful launch of award winning timepiece “One Hertz”the world’s first independent dead seconds series wristwatch ; the Netherlands based watchmakers Bart and Tim Grönefeld unveil their new model in the same One Hertz line  with a revealing open dial to showcase the complex mechanics within.

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

Grönefeld “One Hertz Techniek” Limited Edition watch

While the dial is dominated by a 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”.

Grönefeld “One Hertz Techniek” Limited Edition watch

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

Gronefeld “One Hertz Techniek” Limited Edition watch

The open dial is such that the mechanics behind each one of the One Hertz’s indications and signature features are subtly – and beautifully – revealed.  At the heart of the hour and minutes subdial at 2 o’clock, we see the hour wheel – logically rotating in 60 minutes – offering a splash of colour and contrast to the largely monochrome movement.

The independent dead seconds – where the second hand advances in full steps of one second instead of the more usually smooth sweeping action of mechanical seconds – features prominently in a large subdial at 7 o’clock. The open dial affords rich views of the large, stainless steel gear train bridge for the dead seconds mechanism, the dead seconds escape wheel and the centre wheel. At the top of seconds dial at 11 o’clock, the lever and spring of the power reserve indicator can also be seen.

The whole ensemble of indications and exposed mechanisms are set off against the dark texture of the hand-frosted mainplate and bridges.

Gronefeld “One Hertz Techniek” watch movement

Turning over the One Hertz Techniek completes the mechanical feast for the eyes with the sumptuous display back featuring no fewer than nine finely-crafted stainless steel finger bridges. The One Hertz is the world’s first series movement with all the bridges in stainless steel.

Grönefeld “One Hertz Techniek” Limited Edition watch

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 Techniek” Limited Edition watch

Winding-Setting mechanism and hacked seconds

With the One Hertz, winding and setting are selected by pushing the crown in, instead of pulling it out – a very ergonomic system. The winding-setting (W S) indicator at 3 o’clock provides a neat visual signal as to the mode selected, and the winding-setting lever and its spring are visible around the indicator thanks to the open dial. What’s more, the counter-poised seconds hand can be ‘hacked’ – i.e. stopped – when ‘setting’ is selected, to ensure maximum precision when adjusting the time.

The “One Hertz Techniek” and the “One Hertz Techniek Nocturne”

While the One Hertz Techniek is available in polished and brushed natural Grade 5 titanium, Bart and Tim Grönefeld have harnessed the talents of Finnish company DIARC, world-renowned for their coating techniques, to offer a striking black DLC coated version as well. Bart and Tim have dubbed this black version the “One Hertz Techniek Nocturne” after ‘nocturne’, the style of painting that depicts scenes evoking night.

Dead seconds

The dead seconds complication was a very respected mechanical complication until the 1980s because it denoted superlative accuracy. It was traditionally derived from other mechanisms such as a constant force device or remontoir d’égalité. However, the popularity of dead seconds faded with the dominance of quartz movements, which also stepped in full seconds. A smooth sweeping second hand came to differentiate mechanical from quartz.

But with the One Hertz and its unique secondary gear train, Bart and Tim Grönefeld have resurrected this long-neglected complication and re-positioned it where the complication originated – on the pedestal of high precision.

The stepping movement of the large second hand of the One Hertz subtly signals its unique mechanism, imperceptible to most, but obvious to haute horlogerie connoisseurs, who will appreciate the sublime, flawless fine-finishing of all 285 components of the calibre G-02 movement.

History of Dead Seconds 

With the introduction of the pendulum in the 17th century, clocks finally became accurate enough to measure seconds. It was not long before a hand indicating seconds on a long clock’s dial signified a precision timepiece. A pendulum with a period – the time to swing forward and back – of two seconds (the most common) resulted in a single tick per second.

The invention of the balance spring, which replaced the pendulum, enabled miniaturisation. As portable pocket watches became more accurate, watchmakers naturally thought to copy the one-second steps of the seconds hand which signified a precision timepiece. However, the rapidly oscillating balance meant that it could not be directly driven as with the pendulum, so it required either a new mechanism if independent, or be driven from another complication e.g. constant force device. While pocket watches have featured independent dead seconds in the past, the Grönefeld One Hertz was the first series wristwatch to feature independent dead seconds.

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.

One Hertz 

The hertz (symbol: Hz) is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon. This SI unit is named after Heinrich Hertz. One Hertz simply means “one cycle per second”.

The second (SI symbol: s), sometimes abbreviated sec., is the name of a unit of time, and is the international base unit of time. To highlight the SI seconds, the One Hertz displays dead seconds with a large seconds hand in its own dial. Hours and minutes are non-SI units of time because they do not use the decimal system so are displayed separately.

Mechanical wristwatch movements often have balance frequencies of 2.5 to 5 hertz, which results in the seconds hand making tiny steps of 5 to 10 steps each second and looking like a smooth movement. The seconds hand of the One Hertz is either stationary (dead) or jumping in a full one-second increment each second.

The “One Hertz” independent dead seconds complication

Displaying dead seconds in a wristwatch without a constant force device is no easy task. The friction of the mechanism has to be absolutely minimal so it does not interfere with the escapement.

Bart and Tim Grönefeld used an independent dead seconds mechanism that is driven from its own secondary gear train with its own power supply. The seconds are driven from one mainspring barrel and the hours and minutes from another. Friction is with this system guaranteed to an absolute minimum and the complication has no adverse influence on the escapement and free sprung balance.

The two mainspring barrels are wound simultaneously from the crown, which features an innovative “push to set”, “push to wind function”, with the mode selected indicated at 3 o’clock. A power reserve indicator at the top of the dead seconds dial keeps track of the 72 hours of autonomy.

The “One Hertz Techniek” watch is a limited edition of 30 pieces.

Technical details

Model: One Hertz Techniek

Features and indications
Independent dead seconds – large dial at 7 o’clock
Hour and minutes – subdial at 2 o’clock
Power reserve indicator at 11 o’clock
Innovative Winding-Setting mechanism
Winding-Setting indicator at 3 o’clock
In-house calibre G-02

Case and dial
Case material: Grade 5 polished and brushed titanium and black DLC (Diamond Like Carbon) coating
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

Movement
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
Main Plate: 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

Grönefeld One Hertz Titanium Collection

Haute Horlogerie brand Grönefeld presents the “One Hertz Titanium” collection, comprising four remarkable models: One Hertz Fire, One Hertz Ice, One Hertz Classic and One Hertz Ruthenium.

Each one features Grönefeld’s own ground-breaking 285-component, independent-dead-seconds movement – where the second hand advances in full steps – housed inside a high-tech, polished, grade 5 titanium case. introduced in 2010, the Grönefeld “One Hertz” was the  the world’s first and only production wristwatch with independent deadbeat seconds.

The latest collection consists of four different models: Four titanium cases, four stunning designs: The flame-orange dial of One Hertz Fire; dashing cool white of One Hertz Ice; and two stylishly traditional One Hertz Classic and One Hertz Ruthenium.

Grönefeld One Hertz Fire Titanium

With the One Hertz Fire, the One Hertz dial has been radiantly reinterpreted in a more casual/muscular layout, with flame-coloured touches that contrast against the dark grey background and blackened hand. The hour and minute subdial at 2 o’clock features an electrifying orange crosshair and number 12 and bright white chapter ring.

Grönefeld One Hertz Fire Titanium watch

The raised seconds sapphire subdial – transparent over the hour and minute subdial – features metallised indices on a resplendent orange background, with a striking inner ensemble of white circles and arcs.

In a scorching shade of orange, the power reserve indicator at 11 o’clock – now outside of the large seconds – and the setting-winding indicator at 3 o’clock look like two leaping sparks. The stark orange-on-black Grönefeld logo at 5 o’clock neatly complements the orange stitching on the hand-sewn matte black strap.

Grönefeld One Hertz watch movement

Specific features

  • Dial: Hour and minutes subdial with orange crosshair and number 12; raised seconds sapphire subdial (transparent over the hour and minute subdial) featuring metallised indexes with orange background; orange power reserve indicator; orange setting-winding indicator; Grönefeld logo and model name in orange on individual screwed down nameplates.
  • Hands: Hours and minutes, long thin counter-poised seconds, power-reserve and setting-winding.
  • Indications: Hours and minutes in subdial at 2 o’clock, Large seconds at 7 o’clock. Power reserve indicator at 11 o’clock. Setting-winding indicator at 3 o’clock.
  • Strap and buckle: Hand-sewn matte black, orange stitching, alligator leather with steel buckle engraved with Grönefeld logo

Grönefeld One Hertz Ice Titanium

One Hertz Ice sees the One Hertz dial dazzlingly reinterpreted in more casual/muscular layout with ice white and smooth silvery touches that show up superbly against the dark grey background and gold-toned hands. The hour and minute subdial at 2 o’clock now features a white crosshair and number 12 together with a silver-toned chapter ring.

Grönefeld One Hertz Ice Titanium watch

The raised seconds sapphire subdial features metallised indices here on a pearly white background, with a striking silver inner ensemble of circles and arcs. The power reserve indicator at 11 o’clock – outside of the large seconds – and the setting-winding indicator at 3 o’clock are in fresh white. The dial is framed by a clean, white outer ring that merges into the grey-on-white Grönefeld logo at 5 o’clock.

Specific features

  • Dial: Hour and minutes subdial with white crosshair and number 12; raised seconds sapphire subdial (transparent over the hour and minute subdial) featuring metallised indexes with white background; white power reserve indicator; white setting-winding indicator; Grönefeld logo and model name in white on individual screwed down nameplates.
  • Hands: Hours and minutes, long thin counter-poised seconds, power-reserve and setting-winding.
  • Indications: Hours and minutes in subdial at 2 o’clock, large seconds at 7 o’clock, power reserve at 11 o’clock, setting-winding indicator at 3 o’clock.
  • Strap and buckle: Hand-sewn matte brown, alligator leather with steel buckle engraved with Grönefeld logo

Grönefeld One Hertz Titanium Classic

The One Hertz Classic indicates hours and minutes on a sub-dial at 2 o’clock and has a large subdial for the dead seconds at 7 o’clock; the innovative setting-winding indicator at 3 o’clock is counter-balanced by the power reserve indicator, placed at 12 o’clock on the hour-minute sub-dial – the classic One Hertz position for this complication. The ensemble of indicators is all the more striking thanks to the stylish, circular micro-guilloche beneath.

Grönefeld One Hertz Titanium Classic watch

Specific features

  • Dial: Silvered base dial. Classic One Hertz Hour and minutes subdial; Classic One Hertz raised seconds sapphire subdial (transparent over the hour and minute subdial), Classic One Hertz power reserve indicator; Classic One Hertz setting-winding indicator, Grönefeld logo and model name on individual screwed down nameplates.
  • Hands: Hours and minutes, long thin counter-poised seconds, power-reserve and setting-winding.
  • Indications: Hours and minutes in subdial at 2 o’clock, large seconds at 7 o’clock, power reserve within large seconds, setting-winding indicator at 3 o’clock.
  • Strap and buckle: Hand-sewn matte black, alligator leather with steel buckle engraved with Grönefeld logo

Grönefeld One Hertz Ruthenium

The One Hertz Ruthenium indicates hours and minutes on a sub-dial at 2 o’clock and has a large subdial for the dead seconds at 7 o’clock; the innovative setting-winding indicator at 3 o’clock is counter- balanced by the power reserve indicator, placed at 12 o’clock on the hour-minute sub-dial – the classic One Hertz position for this complication. The ensemble of indicators on its almost black ruthenium dial is very stylish and sophisticated.

Grönefeld One Hertz Ruthenium watch

The One Hertz Ruthenium in a polished and brushed titanium case is a perfect combination for a beautiful and comfortable to wear dress watch.

Specific features

  • Dial: Dark ruthenium base dial. Classic One Hertz Hour and minutes subdial; Classic One Hertz raised seconds sapphire subdial (transparent over the hour and minute subdial), Classic One Hertz power reserve
    indicator; Classic One Hertz setting-winding indicator, Grönefeld logo and model name on individual screwed down nameplates.
  • Hands: Hours and minutes, long thin counter-poised seconds, power-reserve and setting-winding.
  • Indications: hours and minutes on a sub-dial at 2 o’clock. Large seconds at 7 o’clock; the innovative setting-winding indicator at 3 o’clock is counter-balanced by the power reserve indicator, placed at 12 o’clock on the hour-minute sub-dial
  • Strap and buckle: Hand-sewn matte black, alligator leather with steel buckle engraved with Grönefeld logo

The “One Hertz Titanium” collection comprising One Hertz Fire, One Hertz Ice, One Hertz Classic and Onze Hertz Ruthenium is available in four limited editions of 30 pieces each.

Technical details

Case
Case crafted in grade 5 polished titanium made of 68 components, security screws, polished bezel and centre band with hand-finished straight graining.
Case dimensions: 43mm x 12.5mm
Engraving: “Titanium” and “Limited 30 pieces” and serial number
Sapphire crystals: Top domed with antireflective treatment both sides, display back with antireflective treatment inside.
Water resistance: 3atm/30m/100 feet.
Crown: Titanium with engraved “G” logo
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.

Movement
Calibre G-02, mechanical hand winding, independent dead seconds, power reserve Indicator and setting indicator.
Movement dimensions: 15 1/4’’’ 34mm x 9,5mm
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, gold excenters
Balance frequency: 21’600 bph/ 3 Hz
Balance spring: Phillips terminal overcoil curve, triangle-style stud
Main Plate: Spotted 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 source
Dead seconds mechanism: Independent mechanism, 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.

Grönefeld One Hertz Platinum Limited Edition

Grönefeld One Hertz – the world’s first series wristwatch featuring independent dead seconds – was awarded Timezone’s Watch of the Year 2011. This watch was launched initially in 2010 as the One Hertz 1912 version. The One Hertz Red Dune version joined in 2011.

This year, the Netherlands based Grönefeld Exclusive Timepieces brand will be introducing their new One Hertz line featuring exclusive platinum case and sophisticated blue dial.

Gronefeld One Hertz Platinum Limited Edition watch

The One Hertz Platinum features Grönefeld’s own proprietary movement of which all 285 parts are hand-decorated to the highest standards.

The One Hertz indicates hours and minutes on a sub-dial at 2 o’clock; large sub-dial for the dead seconds; power reserve indicator at 12 o’clock; and an innovative setting-winding indicator at 3 o’clock. This ensemble of indicators is all the more striking thanks to the sophisticated blue dial background, which perfectly complements the regal tones of the precious metal platinum case.

The One Hertz Platinum’s setting and winding is also extremely ergonomic, selected by pushing the crown in, rather than pulling it out.

Grönefeld One Hertz Platinum Limited Edition watch

Dead seconds – where the second hand advances in full steps of one second instead of an apparently smooth sweeping action – was a very respected mechanical complication until the 1980s. However, its popularity then died with the dominance of quartz movements, which also stepped in full seconds. A smooth sweeping second hand came to differentiate mechanical from quartz.

With the One Hertz and its unique secondary gear train, Tim and Bart Grönefeld have resurrected this long-neglected complication and re-positioned it where the complication originated: On the pedestal of high precision.

The quartz-like movement of the large second hand of the One Hertz subtly signals its unique mechanism, invisible to most, but obvious to haute horlogerie connoisseurs, who will appreciate the sublime, flawless fine-finishing of the Grönefelds’ own calibre G-02.

The One Hertz Platinum, with exclusive platinum case and sophisticated blue dial, will be unveiled at Baselworld 2012 (Hall 5.1 booth C.01). The “One Hertz Platinum” is a limited edition of 12 pieces.

Technical details

Model: Grönefeld One Hertz Platinum Limited Edition

Features
Indications: Hours and minutes in subdial at 2 o’clock, large seconds at 7 o’clock, power reserve, setting-winding indicator at 3 o’clock.

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 crafted in platinum, security screws, polished bezel and centre band with hand-finished straight graining.
Case dimensions: 43 mm x 12.5 mm
Sapphire crystals: Top domed with antireflective treatment both sides, display back with antireflective treatment inside.
Water resistance: 3atm/30m/100 feet.
Crown: With engraved “G” logo
Dial: Hour and minutes subdial, raised seconds sapphire subdial (transparent over the hour and minute subdial), power reserve indicator, setting-winding indicator, Grönefeld logo and model name on individual screwed down nameplates
Hands: Hours and minutes, long thin counter-poised seconds, power-reserve and setting-winding.
Strap and buckle: Hand-sewn matte black, alligator leather with platinum folding buckle

Movement
Calibre: G-02, mechanical hand winding, independent dead seconds, power reserve Indicator and setting indicator.
Movement dimensions: 35mm x 9.4 mm
No. of parts: 285 parts
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/ 3 Hz
Balance spring: Phillips terminal overcoil curve, triangle-style stud
Main Plate: Spotted 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 source
Dead seconds mechanism: Independent mechanism, 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.

Grönefeld “One Hertz Dune” Red Gold Limited Edition

In 2010, Dutch watchmakers Tim and Bart Grönefeld presented “One Hertz”, the world’s first and only production wristwatch with independent dead seconds. Its first edition, the “One Hertz 1912” was consisted of 12 limited edition timepieces featuring stainless steel case.

Gronefeld "One Hertz Dune" Red Gold Limited Edition watch

Following the success of One Hertz 1912 edition, Grönefeld presents “One Hertz Dune” red gold in a limited edition of 20 pieces.

Grönefeld "One Hertz Dune" Red Gold Limited Edition watch movement

The One Hertz features Grönefeld’s own proprietary movement and indicates hours and minutes on a sub-dial at 2 o’clock; large sub-dial for the dead seconds; power reserve indicator at 12 o’clock; and an innovative setting-winding indicator at 3 o’clock. Setting-winding is ergonomically selected by pushing the crown in rather than pulling it out.

Grönefeld "One Hertz Dune" Red Gold Limited Edition watch

Technical details

Model: Grönefeld “One Hertz Dune” red gold
Edition : Limited edition of 20 pieces

Movement
Calibre: G-02, mechanical hand winding, independent dead seconds, power reserve Indicator and setting indicator.
Movement dimensions: 35mm x 9.4 mm
No. of parts: 285 parts
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/ 3 Hz
Balance spring: Phillips terminal overcoil curve, triangle-style stud
Main Plate: Spotted rhodium plated nickel silver
Bridges: Stainless steel hand bevelled, micro-blasted, circular grain on the top, relief engraved on micro blasted surface
Gearing: two independent gear trains each with their own energy source
Dead seconds mechanism: independent mechanism, 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.

Case
18ct 5N rose gold, limited edition of 20 pieces, gold security screws
Polished bezel and centre band with hand-finished straight graining.
Case dimensions: 43 mm x 12.5 mm
Sapphire crystals: top domed with anti-reflective treatment both sides
Display back with anti-reflective treatment inside.
Water resistance: 3atm/30m/100 feet.
Crown: Rose gold with engraved “G” logo

Dial
Hour and minutes subdial, raised seconds sapphire subdial (transparent over the hour and minute subdial), power reserve indicator, setting-winding indicator, Grönefeld logo and model name on individual screwed down nameplates
Hands: Hours and minutes, long thin counter-poised seconds, power-reserve and setting-winding.

Strap and buckle
Hand-sewn matte black, alligator leather with rose gold engraved tang buckle to match case.

Grönefeld One Hertz 1912 – The World’s First Independent Deadbeat Seconds Series Wristwatch

Grönefeld Exclusive Timepieces, an independent luxury watch brand founded by Dutch watchmakers Tim and Bart Grönefeld present “One Hertz”, the world’s first and only production wristwatch with independent deadbeat seconds (secondes morte in French).

While rare, the deadbeat seconds complication does exist, but to date has been derived from other mechanisms, usually a constant force device or remontoir d’égalité.

The Grönefeld One Hertz features a completely original in-house developed movement indicating hours and minutes on a sub-dial at 2 o’clock, a large sub-dial for the deadbeat seconds filling the majority of the dial with a power reserve indicator at 12 o’clock, and a setting-winding indicator at 3 o’clock. Setting-winding is ergonomically selected by pushing the crown instead of pulling it out.

Gronefeld One Hertz 1912 - The World's First Independent Deadbeat Seconds Series Wristwatch

Deadbeat seconds – where the second hand advances in full steps of one second instead of an apparently smooth sweeping action – was a very respected complication until the 1980s; however, its popularity died with the dominance of quartz movements, which also stepped in full seconds. A smooth sweeping second hand came to differentiate mechanical from quartz.

With their new One Hertz, with its unique secondary gear train, Tim and Bart Grönefeld have resurrected this long neglected complication and re-positioned it where the complication originated, i.e. on the pedestal of high precision.

The quartz-like movement of the large second hand of the One Hertz subtly signals its unique mechanism, invisible to most but obvious to haute horlogerie aficionados who will appreciate the flawless fine-finishing of the in-house developed Calibre G-02.

Gronefeld One Hertz 1912 - The World's First Independent Deadbeat Seconds Series Wristwatch

The One Hertz launches with a subscription-only limited edition of 12 pieces called the “One Hertz 1912” –1912 was the year Tim and Bart’s grandfather qualified as a watchmaker.

History of the Deadbeat Seconds

With the introduction of the pendulum in the 17th century, clocks finally became accurate enough to measure seconds. It was then not long before a hand indicating seconds on a long clock’s dial signified a precision timepiece. A pendulum with a period – the time to swing forward and back – of two seconds (the most common) resulted in a single tick per second.

The invention of the balance spring, which replaced the pendulum, enabled miniaturization. As portable pocket watches became more accurate, watchmakers naturally thought to copy the one-second steps of the second hand, which signified a precision timepiece; however, the rapidly oscillating balance meant that it could not be directly driven from the oscillator as with the pendulum, so it either necessitated a new mechanism if independent, or it had to be driven from another complication e.g., a constant force device.

While pocket watches have featured independent deadbeat seconds in the past, the Grönefeld One Hertz is the first wristwatch featuring independent deadbeat seconds. The Grönefeld One Hertz is unique among wristwatches in that its deadbeat seconds are powered by a secondary gear train that is independent of the gear train for the hour and minute indications.

Gronefeld One Hertz 1912 watch movement

One Hertz

The hertz (symbol: Hz) is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon. This SI unit is named after Heinrich Hertz. One Hertz simply means “one cycle per second”.

The second (SI symbol: s), sometimes abbreviated sec., is the international base unit of time. To highlight the SI seconds, the One Hertz displays deadbeat seconds with a large second hand in its own dial. Hours and minutes are non-SI units of time because they do not use the decimal system so are displayed separately.

Mechanical wristwatch movements often have balance frequencies of 2.5 to 5 hertz, which results in the second hand making tiny steps of five to 10 steps each second and looking like a smooth movement.

The “One Hertz” independent deadbeat seconds complication

Displaying deadbeat seconds in a wristwatch without a constant force device is no easy task. The friction of the mechanism has to be absolutely minimal so it does not interfere with the escapement. Tim and Bart Grönefeld used an independent deadbeat seconds mechanism that is driven from its own secondary gear train with its own power supply.

The seconds are driven from one mainspring barrel and the hours and minutes from another. Friction with this system is guaranteed to an absolute minimum and the complication has no adverse influence on the escapement and free-sprung balance.

The two mainspring barrels are wound simultaneously from the crown, which features an innovative “push to set, push to wind” function, with the mode selected indicated on the dial at 3 o’clock. A power reserve indicator at the top of the deadbeat seconds dial keeps track of the 60 hours of autonomy.

Technical details

Model: Grönefeld One Hertz 1912

Movement
Calibre G-02, mechanical hand winding, independent deadbeat seconds, power reserve indicator and setting indicator
Movement dimensions: 35mm x 9.4mm
Parts: 254
Jewels: 39, set in gold chatons
Power reserve: 60 hours
Barrels: Two barrels, one for the going gear train and one for the independent deadbeat seconds mechanism; both barrels are wound at the same speed and in the same direction
Balance wheel: 9.12mm free-sprung Gyromax balance wheel
Balance frequency: 21’600 bph/2.5Hz
Balance spring: Phillips terminal overcoil curve, triangle-style stud
Main Plate: Spotted and snailed rhodium plated nickel silver
Bridges: Stainless steel, hand-bevelled, micro-blasted centre and the underneath spotted, circular grain on the top, relief engraved on micro-blasted surface
Gearing: Two independent gear trains each with their own energy source
Deadbeat seconds mechanism: Independent mechanism, cam with 30 teeth on the going gear train on the seconds wheel, escape wheel on the seconds wheel of the independent gear train, double lever with 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

Indications
Hours and minutes in sub-dial at 2 o’clock, large seconds at 7 o’clock, power reserve, setting-winding indicator at 3 o’clock

Case
Case: stainless steel, limited edition of 12 pieces, gold security screws, polished bezel and centre band with hand-finished straight graining
Case dimensions: 43mm x 12.5mm
Sapphire crystals: top domed with anti-reflective treatment both sides, display back with anti-reflective treatment inside
Water resistance: 3atm/30m/100feet
Crown: Stainless steel with engraved “G” logo

Dial
Hour and minutes sub-dial, seconds sub-dial, power reserve indicator, setting-winding indicator, Grönefeld logo and model name on individual screwed-down nameplates
Hands: Hours and minutes, long thin counter-poised seconds, power reserve and setting-winding

Strap and buckle
Hand-sewn matte black, alligator leather with stainless steel engraved tang buckle

Grönefeld GTM-06 Tourbillon Minute Repeater

This chiming wristwatch, the most complicated wristwatch ever created in The Netherland’s history, is a so-called tourbillon with a minute repeater mechanism, able to sound the exact time on tiny gongs held within its case. In the world of horology this type of wristwatch represents the watchmaker’s Mount Everest in terms of the difficulties it contains, requiring more than 6 months of careful construction, assembly and regulation before completion.

Grönefeld GTM-06 Tourbillon Minute Repeater watch

The GTM-06 is the first in a line of wristwatches planned by the Oldenzaal based watchmakers Bart and Tim Grönefeld, who have spent 4 years of hard work before the realization of this new timepiece would become a reality.

Gronefeld GTM-06 Tourbillon Minute Repeater watch

With a contemporary and masculine look, the GTM-06 Tourbillon Minute Repeater wristwatch is available in a strictly limited edition of 10 pieces in 18 carat 4N gold and 10 in 950 platinum, priced at Euro 325,000 and 385,000 accordingly.

Gronefeld GTM-06 Tourbillon Minute Repeater watch in gold

With its musical nature, utilizing miniature hammers and cathedral gongs to chime the hours, quarters and minutes as requested by the user, in combination with a tourbillon regulating device, the Grönefeld tourbillon minute repeater makes mechanical demands on watchmakers that go far beyond the majority of watches on offer today. Only a handful of watchmakers in the world, either inside or outside of Switzerland, are able to deal with horological creations comprising this type of extreme complexity.

Grönefeld GTM-06 Tourbillon Minute Repeater watch

The watch differs from other repeater wristwatches in a number of details. This is first and foremost a man’s repeater wristwatch, as one can see in its full bodied and forceful lines. But there is also an acoustic reason behind this design aspect, as the case volume allows the gongs to develop a full and pure sound. The lugs, which also convey the full outlines of the case to the special galuchat strap, appear to be straightforward but they are not.

Gronefeld GTM-06 Tourbillon Minute Repeater watch case back movement view

Using specially developed micro-machining techniques invisible from the exterior, the lugs are specially channeled in order to allow the resonance of the case not to be dampened by their mass. This is the result of experiments and vast experience that both Tim and Bart developed in the course of years of work on minute repeater mechanisms, as well as careful listening and tuning of the sounds the minute gongs produce. The GTM-06 also utilizes a Cathedral type gong that has a longer winding within the confines of the case, thus providing the fullest possible tone achievable.

Grönefeld GTM-06 Tourbillon Minute Repeater watch in platinum

The dial is formed by the beautifully finished movement itself, decorated with Geneva stripes, perlage, anglage and perfectly polished screws, hands, indexes and springs. Black polish, the most impossibly demanding and difficult ‘dark art’ of fine finishing found only in the most expensive watches, is used extensively throughout the movement.

Gronefeld GTM-06 Tourbillon Minute Repeater platinum watch

Even those areas never to be seen by the user are given exquisite finishing on a level that has become increasing rare in the world of haute horlogerie today. The modern styled chapter ring of black onyx is adorned with highly polished hour indexes that catch the light at every angle to provide a subtle and discrete view of the time. Only the fine finishing of the parts before assembly starts takes more than 2 months of intensive work in several stages to complete.

Grönefeld GTM-06 Tourbillon Minute Repeater

The watches will first be available with 18 carat rose gold cases, and shortly after with a minimal number available in 950 platinum during the first year. There are plans to develop a limited series stealth model in black DLC coated titanium during the course of 2009, and there are many short, medium and long-term plans to follow as the brand develops and grows.

Grönefeld GTM-06 Tourbillon Minute Repeater box

The Grönefeld GTM-06 is delivered in an ultra high-end presentation box of unparalleled quality and design. The hand finished, black piano lacquer box contains two shelves, the uppermost a leather-lined tray with the watch, a comprehensive leather-bound instruction book, guarantee certificate and space for cuff links or other accoutrements. Below is a special, ventilated wooden tray for cigars.

Another level lower, one pushes on the engraved aircraft aluminum inlay with Grönefeld logo, and a secret drawer appears containing a Davidoff (Dupont) black lacquer gas lighter and two cigar cutters.