1941 Principia automatic | Light blue dial
The Grönefeld 1941 Principia Automatic 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 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. A sapphire case back has been fitted to confer a spectacular view on the extensively hand finished movement with their well known stainless steel bridges and a 22K solid gold oscillating weight.
Each movement is finished and assembled by hand. To emphasize the manual labour involved a gold plate, engraved with an individual number, is applied to the movement.

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.
Let's take a closer look at the case. 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.
Last but not least, how did the Principia get its name? 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 to select the 'Principia' name for their first watch with automatic winding mechanism.
A movement for connoisseurs
The Grönefeld 1941 Principia Automatic 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 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. A sapphire case back has been fitted to confer a spectacular view on the extensively hand finished movement with their well known stainless steel bridges and a 22K solid gold oscillating weight.
Each movement is finished and assembled by hand. To emphasize the manual labour involved a gold plate, engraved with an individual number, is applied to the movement.
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.
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 escapement is adjusted to heat-cold, isochronism and six positions.
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.

technical specifications
Calibre
G-06
Movement dimensions
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 dimensions
Diameter: 39,5 mm
Thickness: 10,5 mm
Water resistance
3 atmospheres – 30 meters – 100 feet
Material
White Gold Au750/Pd210 (Non Rhodium plated), Red Gold Au750 5N or Stainless Steel (1.4435).
Engraving: Grönefeld and the individual number
Crown
Case matching material, engraved with The Horological Brothers 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. 20mm-18mm
Buckle
Pin buckle made in Red Gold Au750 5N, White Gold Au750/Pd210 (non rhodium plated) or Stainless Steel 916L 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
Stainless Steel 74 Grams
Red Gold 97 Grams
White Gold 97 Grams



















































































































