Emmanuel, known as quattro on WatchProSite, delves into the fascinating history of Patek Philippe's rare André Bornand tourbillon calibers. His meticulous research unearths details about these exceptional movements, originally designed for the Geneva Observatory trials. This article provides an invaluable look into these horological treasures, many of which reside in prestigious museums or private collections.
During the 1940s, 50s and 60s, André Bornand (1892-1967), who was a professor at the Geneva School of Watchmaking and one of the most famous tourbillon specialists of the 20th century, designed a few tourbillon calibers specifically for the Geneva Observatory trials.
Five of them, built between 1958 and 1966, are rectangular, referenced as Caliber 34T and are numbered 861.490 and 866.500 to 866.503. They feature an unusual 50 seconds tourbillon and have a Guillaume compensating balance and steel Breguet balance spring, as well as a cage made of beryllium bronze (21,600 vph, 57h of power reserve). These movements were cased later, in the early 1980s, and the watches were given the ref. 3834:
- The watches with movement n° 861.490 & 866.503 belong to the Patek Philippe Museum
- The watch with movement n° 866.500 belongs to the Beyer Museum
- The watch with movement n° 866.502 was sold at Antiquorum in 1989
- The watch with movement n° 866.501 is nowhere to be found at the moment
Another one, completed in 1945, is round and numbered 861.115. It has a bimetallic Guillaume balance and steel Breguet overcoil, and beats at 21,600 vph. In 1987, it was cased, given ref. number 3699 and worn as a personal watch by Mr. Philippe Stern.
Let's dive in!
Best, Emmanuel
A/ THE BEYER EXAMPLE, movement n° 866.500 (cal. 34T, watch ref. number 3834)
credit: hodinkee &
219 here on WPS
B/ THE EXAMPLE SOLD AT ANTIQUORUM, movement n° 866.502 (cal. 34T, watch ref. number 3834) (
lot 299 at Antiquorum, Geneva, 9th April
1989)
credit: antiquorum
C/ THE TWO EXAMPLES OF THE PATEK PHILIPPE MUSEUM (cal. 34T, watch ref. number 3834)
1/ Movement n° 866.503
credit: zhuanlan.zhihu (1), Pinterest (2)
DCC here on WPS (3), Treasures of the Patek Philippe Museum (4), Patek Philippe (5), Martin Huber & Alan Banbery,
Patek Philippe, Geneve. Montres-bracelets - Armbanduhren - Orologi da polso - Wristwatches, 1988 (6) & marcgebauer (7)
2/ Movement n° 861.490 (left) & 866.503 (right) 
credit:
charlitos on relojes-especiales
D/ THE PHILIPPE STERN EXAMPLE, movement n° 861.115, watch ref. 3699
credit: Patek Philippe Museum
E/ LINKS FOR FURTHER READING
Talking watches with René Beyer
About the Patek Philippe Calatrava Ref. 600
The Patek Philippe Calatrava reference 600 is a significant early example within the Calatrava lineage, representing the foundational design principles of the collection. This reference predates many of the more complex complications found in later Patek Philippe models, focusing instead on purity of form and legibility. It embodies the brand's commitment to traditional watchmaking and understated design, setting a precedent for subsequent Calatrava iterations.
This particular reference typically features a case crafted from precious metals, often yellow gold, with a modest diameter that aligns with historical preferences for dress watches. The movement powering the reference 600 would be a manual-winding caliber, reflecting the mechanical advancements of its era. The crystal would have been a material common for the period, protecting a dial designed for clarity and timeless appeal.
For collectors, the reference 600 holds importance as an early and unadorned representation of the Calatrava's core aesthetic. Its simplicity and historical context make it a desirable piece for those interested in the evolution of Patek Philippe's most enduring dress watch collection. Variants within this reference would primarily involve different dial finishes or case materials, maintaining the essential Calatrava character.
Specifications
- Case
- 18k yellow gold
- Diameter
- 31mm
- Dial
- Silver
- Crystal
- Acrylic
About the Fiat Ref. 1966
The 1966 Ford Mustang represents a significant year for the model, building on the initial success of its introduction. This reference is part of the first generation, which established the Mustang as a distinct category of American automobile. It continued to offer a range of body styles and engine options, allowing for considerable personalization and appealing to a broad market segment. The 1966 model year saw refinements rather than radical changes, solidifying its design language and market position.
The vehicle's construction typically featured a steel unibody chassis. Various engine configurations were available, including inline-six and V8 options, paired with manual or automatic transmissions. Specific dimensions varied slightly depending on the body style, such as coupe, convertible, or fastback. The interior offered a functional layout, with instrumentation focused on driver information.
This reference holds interest for collectors due to its place in the early history of the Mustang and its enduring popularity. The availability of different engine and trim levels means that specific examples can vary widely in their features and performance. It remains a recognizable and sought-after classic, often celebrated at automotive events worldwide.
Specifications
- Caliber
- B18
- Case
- Steel
- Diameter
- 40.5mm
- Dial
- Black
- Water Resist.
- 100m
- Crystal
- Glass
