The Reason
An example of an original Corne de vache 1955 Vacheron Chronograph.
(Less than 40 examples are known to have been made.)
Introduction/functions
A classic 1950's manually wound chronograph with 30 minute-recorder. 18k gold case with screwed on solid cased back. Although well used for over half a century the watch is in good condition and shows few, worn surfaces. The equivalent design reproduced today by Vacheron Constantin has become a classic design icon from the brand.
Please move the cursor across the image below, (or by finger on a smart phone), to rotate the watch.
Rear view of the solid case back with 12 facets, associated to the key of the same form which would be used to tighten and remove the back.
Before the 1980’s it was common that most watches had a solid case back concealing the calibres.
Profile of the case.
Compared to the modern version the shoulders were more delicate in construction. The glass was perspex apposed to sapphire and the winding crowns did not have the brands logo.
The case back removed showing the inner-cap which partially protected the movement from magnetism and held it in place.
The small raised section in the centre of the cap pushes against the inner case back to hold the movement solidly in place replacing the need for case screws.
The inner cap removed and the inside of the case back shown with the serial number associated to the archives, hall marks and brand.
The movement calibre 492, viewed without the inner cap or case back.
It is a reference to high end watchmaking that pre-dates the use of sapphires set into case backs that despite being hidden the movements were hand finished and highly decorated.
The movement with dial and hands removed from the case.
Full view of the movement.
The decoration is a mix of Geneva stripes, hand polished angling, straight graining mirror finished polishing and spotting (pearlage). The basic calibre was a Valjoux, which was taken by Vacheron Constantin and personalised and decorated to their design criteria.
Underside of the dial and the dial side of the movement.
The dial is made from silver and the gold batons and logo are riveted in place.
The setting/winding mechanism is simple and strong. And after in excess of 50 years of life has worn very little.
The 18k and blued steel hands.
The balance wheel and cock removed.
The balance pivots oscillate in fixed jewels and end stones. Although the invention of shock protection to protect the pivots against being broken in case of impact had been created several years before hand, there was still a period of transition until virtually all mechanical calibres used shock absorbers.
The balance cock with regulating index and kidney shaped stud holder.
The Glucydur balance with screws and hand lifted overcoil.
The Swiss lever and cock removed.
The two pins standing vertically in the main-plate limit the movement of the Swiss lever.
The lever and cock is angled and the angles hand polished with a mirror finished.
The column wheel in the low-centre of the image controls the operations of the surrounding levers.
Historically the column (or pillar) wheel was one of the first systems used in chronographs and has always been associated to to high-end watchmaking.
The coupling clutch removed.
The coupling clutch transmits power from the upper fourth wheel to the central chronograph seconds wheel.
The upper fourth wheel removed allowing a clearer view of the Geneva stripes decoration, mostly hidden by the chronograph mechanism.
The upper fourth wheel is a friction fit onto the extended fourth wheel pivot.
The return to zero hammer removed.
The hammer spring acts on the small screw on the hammers surface to return it to its rest position.
The hammer piece and its spring, which returns it to its neutral-rest position after the 4 o’clock pusher has been pushed.
With the modern version of this watch the hammer spring pushes the hammers to return to zero the counters. With this calibre the force of the operators finger pushers the hammers to return to zero the counters, and the spring pulls the hammers back into its relaxed position.
The minute and chronograph seconds wheels removed.
The cock which holds in place the chronograph wheels.
To the left the minute counter wheel, and the chronograph seconds wheel to the right.
The operating lever removed, showing the lower lever which pushes onto the hammers (when in place).
The intermediate minute recorder wheel.
The chronograph mechanism removed with the exception of the column wheel.
The escape wheel and fourth wheel bridge removed.
The forth wheel turns once a minute. It both drives the chronograph and carries the constant small seconds hand.
The main bridge removed revealing the gear train including barrel.
Recto-verso of the main bridge.
The heavy angling was executed manually, as was the assembly and adjustments.
The under side of the bridge showing the ratchet click and upper crown wheel.
The fully dismantled main-plate (except for the setting mechanism).
The gear train and barrel.
Summary
During this period there were few ‘different’ quality chronographs calibres being produced. This Valjoux 23 calibre was adopted by a multitude of high end brands and adapted as per the requirements of each company. It was, and remains a precision work-horse of a movement which will continue to survive the test of time. The watch design and the calibre have become classics in the history of watchmaking.
To learn more about Vacheron Constantin