In the past – large enterprise

In the sixties, Zenith Factory was considered a major employer in Le Locle region.
According to contemporaries’ memoirs, the number of hands sometimes achieved thousands of people.
Only this figure compare with Le Locle population – 12 000 – explains the watch factory’s former economic importance for the city.
Today, about 250 people work here. 150 employees are engaged in manufacturing, 70 of them – watchmakers.
Labor turnover is high: about 20% of staff is updated annually – partly because numerous watch factories and suppliers from Swiss Jura lead a real struggle for skilled personnel, making them attractive offers, which are hard to refuse.
If 40 years ago production was conducted solely on machine tools with cam-driven mechanisms, today they use completely different means and methods.
Construction of watch movements and design of new models are carried out completely on computers.
The design of clock mechanism always starts with its link with the outside world, i.e., clockwork shaft.
Other details are added to it and then it is expanded in all planes, until monitor shows final version.
Due to a three-dimensional image, watches and arrangements can be seen in all perspectives and cross sections.
This construction method allows making changes in the project at any time.
This is particularly important when developing new models that can go into production only when the firm’s head gives his consent.

To save time, computer images of new watches are first examined in two-dimensional form, to provide desired changes in advance.
And only then they produce a prototype, which, thanks to a precise pre-design, can already be considered a fully working watch item.
In conclusion, it comes to a tool shop, where, as a rule, they produce all necessary precision cutters and other tools for clockwork processing.
Finally, it is the turn of already mentioned modern machines.
Most of the processed details are then trimmed and decorated by hand.
Work is performed with multiple intermediate checks of size precision.
In the end, this control is a guarantee of the clock’s accuracy.
And Zenith observes this condition despite all changes taking place within ancient manufacture walls.


El Primero (Spanish: “First”) was not only the first automatic chronographic mechanism in the world, it was also the first with the balance, operating at a frequency of 36 000 half-vibrations per hour, or 5 Hz.
Therefore, the first EI Primero model’s balance committed almost a fantastic number – about 10 billion (9 460 800 000) half-vibrations from the date of issue in January 1969.
Because of high frequency balance vibrations and necessary wheel escapement high speed, a new caliber, designated as 3019 RNS, was greeted with great skepticism in the industry.
The fact that the anchor wheel was turning so fast, that there was a real threat to spray oil by anchor wheel teeth under a centrifugal force.
As a consequence, they would need a strong wheel rotation gear to balance, very quickly and without lubrication, which initially would lead to inaccurate move, and under certain circumstances, would later led to the clock stopping.
However, skeptics underestimated Zenith engineers and specialists on lubricants.
They renounced the use of conventional watch oils, when lubricating 3019 PHC caliper balance parts.
Instead, they use a dry lubricant on the basis of bisulfite molybdenum.
Of course, Zenith strived to create a clock mechanism design that operates at a frequency of 36 000 half-vibrations per hour, not only because of the belief that rapidly oscillating systems are less susceptible to interference.
Designers also thought about practical use of such chronographs.
El Primero was the first chronograph that allowed measuring fractions of a second due to the fact that central chronograph seconds hand moved to tenth fractions of a second in jumps.