Bart and Tim Grönefeld, the award-winning Horological Brothers, present their first chronograph watch. Named 1941 Grönograaf, this classic chronograph incorporates several ingenious details.
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.
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.
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.
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.
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.
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.
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.
Model: Grönefeld 1941 Grönograaf
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
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
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
Extended Lancette hands for hours and minutes
Poised Breguet style chronograph hands
Flame-blued steel and mirror polished centers
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)
Tantalum: 108 grams
Stainless Steel: 85 grams
Stainless steel version: € 155,000 (Limited edition of 188 pieces)
Tantalum version: € 165,000 (Limited edition of 25 pieces)