In the late 1950s Soviet physicist Feodosii Fedchenko began working on the development of an extremely accurate pendulum clock that was also robust and reliable (always a hallmark of Soviet watch and clock design!). It was hoped these clocks could be used in the more inhospitable and remote corners of the USSR.
By the late 1960s he had succeeded in designing the most accurate mechanical clock in the world and the ‘All-Union Scientific Research Institute of Physicotechnical and Radiotechnical Measurements’ in Leningrad began producing the AchF series of pendulum clocks, which had an average accuracy of approximately 0.002 seconds per day.
All together about 50 of these clocks in various configurations were produced from the late 1960s through the mid 1970s, when quartz technology became a less expensive alternative.
These battery powered ‘astronomical’ regulator clocks feature an invar pendulum, constant pressure, isochronous suspension, temperature compensation, and short central impulsing. The electronically impulsed master pendulum swings with a 2-second period inside a heavy glass bell-jar containing an almost total vacuum.
The master clock mechanism does not have a dial. Instead it produces 1-second beats that are sent via an electrical wire to a slave clock that is mounted on the framework holding the master clock mechanism.
While I do not (yet) have a Fedchenko master clock in my collection, I was lucky recently to receive a Fedchenko slave clock with the serial number 4.
The dial of this clock is signed ‘Standard’ – an understandable compromise considering how difficult it would be to fit the signature ‘All-Union Scientific Research Institute of Physicotechnical and Radiotechnical Measurements’ between the large upper sub-dial and the central pinion
This is an interesting clock for several reasons.
First, is the quality of its construction. It is made from heavy brass and assembled with blued screws. It has a beautifully etched metal dial and is protected by a thick beveled glass face. It is 35 cm in diameter and weighs a whopping 9 kg.
Second, it is a regulator, with separate dials for hours, minutes and seconds. This is the only authentic Soviet-made regulator of any kind that I have so far seen.
I have attached a few photos of the new Fedchenko slave and also a photo of a typical Fedchenko master clock on its framework with its slave clock (model AchF-3). There is more information and several more photos on my website. Go to record number 1477.