Let’s answer some of the common watch performance questions.
NB: this section is based upon general information and issues and may not apply in all cases. Remember, watches are intricate pieces of technical machinery and it can take time and investigation to get to the core of an issue.
FYI the average hairspring in a mechanical watch oscillates (moves back and forward) over 500 million times per year when work regularly.
The hairspring is a flat spiral spring consisting of between 12 to 15 spirals, weighs around 1mg and is 0.03 mm thick. It serves a single purpose: when it coils and uncoils, it propels the balance wheel which oscillates around its axis to accumulate the energy required to power the movement. Both are made so that this oscillation is as regular as possible in order to ensure stability and precision.
Despite the fact that it converts kinetic energy into information (the time) in a very precise and efficient manner, many things conspire to prevent this component from working properly (ie at a stable frequency). Centuries of scientific endeavour have tried to make it impervious to all outside influences but none have yet succeeded. Some of the factors that influence and disrupt the hairspring’s performance include: magnetic field interference, air pressure changes and temperature variations. All these factors modify the shape, length and properties of the exceptionally thin and long spring, which in turn alters its oscillation frequency and therefore interferes with timekeeping. So, in short, be kind to your timepiece and it will be faithful to you.
The hairspring is the lightest and most crucial of all watchmaking components. It is fitted onto the balance wheel and acts as the heart of the watch.
Firstly, a new mechanical watch may have a ‘run in’ time of 1-6 months (similar to a new car engine). During this period the movement oils will settle down and, through regular use, all components will become lubricated and free flowing. Be aware that external factors such as temperature and resting position may affect accuracy of a timepiece and there will be differences between movements, but don’t get too bogged down in detail because even within a watch series there can be alterations – this is part of the deal with mechanical, hand-assembled objects. As a guide, accepted tolerances can fall within these ranges:
Modern non COSC certified watches
Lower end +/- 10 sec /day
Typical +/- 5 sec/day
Excellent +/- 3 sec/day
Modern COSC certified watches
Lower end +6/- 4 sec /day
A few up front questions will guide you…
If your watch has stopped completely for any of the reasons above, please unscrew/disengage the crown to stop the watch trying to move thus avoiding further wear/damage and have it assessed and repaired asap. (Especially important in the case of impact/water damage)
An erratic stop/start is usually due to magnetic interference which will stop the movement when it comes into contact with a magnetic field and restart once it is moved away.
Sources of magnetic field interference are on the increase and include: loud speakers, cellular phones, magnetic closure systems for handbags, glasses cases, wallets, refrigerators, and cupboards, office equipment, anti-rheumatic bracelets, magnets, landline telephones, televisions, computers and tablets, laptop computers, audio and video systems, MP3s, microwave ovens, hair-dryers, hi-fi equipment, domestic appliances, and induction hobs. Consequently, it is quite common to magnetize a watch unwittingly.
How to test: This can be tested by holding your watch to a compass (not a digital compass or smart device as this creates a magnetic interference itself)… go for the old-school hand held compass. If the watch moves the needle when you hover it over the compass, then it is a sign that your watch may be magnetised and will need to be professionally demagnetised.
FIX: You may be able to reset the time and that will suffice, but if problem persists it will need to be professionally demagnetised.
Mechanical timepieces may also lose or gain time when affected by strong magnetism, though not as much as with quartz timepieces. Once a mechanical timepiece has been affected, magnetism remains in the movement even if it is moved away from the magnetic source. Accuracy problems may persist after a long time so it is necessary to demagnetise (repair) the timepiece professionally.
How to test: Hold your watch to a compass (not a digital compass or smart device as this creates a magnetic interference itself)… go for the old-school hand held compass. If the watch moves the needle when you hover it over the compass, then it is a sign that your watch is magnetised and will need to be professionally demagnetised.
FIX: Contact your retailer or authorised repairer as your timepiece will need to be professionally demagnetised.
The power reserve of a watch will depend upon the type of movement and how it is worn. This is a general guide.
Quartz/battery watches: will function until the battery runs out or interference occurs (see magnetic fields in the point above).
How to test: A quartz watch with a second hand will indicate decreasing battery power by jumping at 4 second intervals. In the absence of a second hand the movement will simply stop.
Possible FIX: a new battery is required, we recommend that the case seals and pressure are tested at the time of battery change to ensure the case is sealed and movement is protected.
Automatic Mechanical watch:
Possible cause: Watch may not be wound fully or receiving adequate motion to take on power through the rotor. Generally speaking, 6-8 hours/day of normal active wear will provide sufficient movement to power the mainspring. Desk jobs or car-based activities where your arm remains stable most of the time could prove insufficient.
How to test: You can conduct a couple of simple observational tests up front to help identify the issue.
Possible FIX: Once the results are in, check the power reserve on non-wear and active days with the table of timekeeping in the section above. If levels are showing within accepted readings you will know it is movement related and may consider a watch winder to ensure power reserve levels are maintained on days of less activity/non-wear. If levels exceed the parameters the issue will require further investigation at the service centre.
This can depend upon the type of movement, how it is worn, the power reserve and other issues.
Please check the notes above as they can all impact the timekeeping of a watch whether it be quartz or mechanic. If it is not an issue related to any of the situations outlined above it could be related to the hairspring.
Excessive gains are generally a result of impact/damage affecting the hairspring which causes it to bank over and overcompensate by running fast.
Possible cause: Unfortunately this is usually due to trauma (even an unnoticed knock in the wrong place can upset the delicate hairspring – see notes above).
FIX: Please unscrew/disengage the crown to stop the movement and return to the service centre asap.