Precision timekeeping - Part Two
Recap
The previous article navigated a course through an array of bewildering watchmaking terms. In addition, it provided an insight into the regulating organ, its relationship with the escapement as well as some of the other parts found within a movement.
Terms such as the flow of time, poising (the need for the balance to run true), beat rate, amplitude, beat error and rate variation were discussed. As any watchmaker will attest, there is much to consider when it comes to ensuring precise timekeeping.
This feature includes the behaviour of the balance, how the movement is regulated and post regulation influences on the rate.
Appraising the behaviour of the balance
The hairspring is attached to the balance staff using a collet and should sit perpendicular to the balance staff. Moreover, the balance staff should be upright. When the balance wheel oscillates backwards and forwards, it should ‘breathe’ concentrically.
If necessary, the watchmaker will make small adjustments to the various coils of the hairspring, ensuring they are arranged concentrically with each coiled section equidistant from its neighbour.
These factors are essential prerequisites before a watchmaker can even think of regulating a movement.
Regulating the movement
The Zeitwinkel caliber ZW0103 is fitted with an index or ‘raquette’ and it is this component which is used to alter the rate of the movement.
As stated previously the hairspring is connected to the balance staff using a collet. At the opposite end, the balance spring connects to a stud. As stated in part one, the Zeitwinkel caliber ZW0103 features a mobile stud holder, a refinement that allows the watchmaker to reposition the balance if required.
The hairspring passes through two curb pins affixed to the raquette. When the watchmaker moves the raquette towards or away from the stud, this changes the effective length of the hairspring, thereby altering the rate.
However, once the rate is adjusted for one position, the process needs to be repeated for additional positions. Zeitwinkel regulates its movements in five positions.
Why regulate a movement in different positions?
Gravity influences various moving parts within a wristwatch. This gravitational influence varies depending on the position in which a watch is held, especially when it is not attached to the wrist. For example, the rate variation may be acceptable when the watch is laid face down on a surface, but be out of tolerance when positioned on its side with the crown pointing upwards. This variance, sometimes termed ‘a positional error’ is primarily due to gravity’s influence on the balance.
Other factors which can influence the rate post regulation
Having expended much energy regulating the movement, the precision of the watch can become impaired by other factors. For example, when a movement is subjected to extreme shocks or exposure to a strong magnetic field, it may affect the rate. In some cases, this may even require the remedial attention of a watchmaker.
An automatic movement should be fully wound when placed on the wrist after a period of inactivity. This is because the energy from the barrel will be at its optimum when fully wound. If the wearer has a very sedentary lifestyle they may wish to manually top up the barrel in order to ensure the escapement receives the perfect supply of energy.
Watches should never be subjected to extreme temperatures (less that 5°C or more than 35°C) as this may harm components due to expansion or contraction.
Lubricants can also influence the rate of a watch. Similar to a car requiring an oil change, a watch should be serviced every 3 years, albeit this depends on the lifestyle of its wearer. This is because lubricants deteriorate with time, causing their viscosity to alter, influencing the behaviour of moving components.
Conclusions
As this two-part feature demonstrates, there are many factors that can influence the performance of a wristwatch. Zeitwinkel has expended much effort designing each component, selecting the finest materials and bringing every constituent part together to deliver precision timekeeping. Moreover, much importance is placed on the process of regulation, drawing on the expertise of incredibly talented individuals who choreograph numerous parts to move precisely in a predetermined way again and again and again…