The Grönefeld Principia combines refined proportions with the exceptional hand-finishing associated with the Dutch independent watchmaker. This stainless steel luxury watch features a light blue dial framed by polished hour markers and striking blued steel hands, creating an elegant contrast. Beneath the surface, the automatic G-06 calibre delivers approximately 56 hours of power reserve and features a distinctive 22K solid gold oscillating weight. The watch is housed in Grönefeld’s signature 1941 case, named in honor of the birth year of the brothers’ father, with its graceful lines and carefully considered proportions offering a sophisticated presence on the wrist.
Through the sapphire crystal caseback, the Principia reveals an extensively hand-finished movement with Grönefeld’s characteristic stainless steel bridges, polished details, and solid gold rotor. Every calibre is individually assembled and finished by hand, with a numbered gold plate incorporated into the movement as a subtle acknowledgment of the craftsmanship behind each timepiece. Continuing a family watchmaking tradition that began in 1912, Bart and Tim Grönefeld have established a reputation for exceptional independent watchmaking that pairs traditional craftsmanship with innovative mechanical engineering, making the Principia a compelling expression of modern haute horlogerie.
TECHNICAL SPECIFICATIONS
Caliber
G-06
Movement dimensions
- Diameter: 32 mm
- Thickness: 5.5 mm
Number of parts
226
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 & 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 dimensions
- Diameter is 39.55 mm with a thickness of 10.5 mm
Water resistance
3 ATM / 30 meters
Material
Stainless Steel
Crown
Case matching material, engraved with The Horological Brothers Logo
Dial
Light blue coloured dial with a solid Sterling Silver 925 base material
Hands
- Extended Lancette hands
- Flame-blued steel and mirror polished centers
- Small poised seconds hand
Strap
Blue buffalo with orange stitching.
Buckle
- Pin buckle made in Red Gold Au750 5N engraved with Grönefeld
- 18mm
Crystals
- 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
Number of components
54 parts
Total weight
Red gold 97 grams
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