The position of a watch determines how gravity affects the moving parts of the movement. In other words, the timekeeping of a watch can vary according to whether it is laid on its back or on its side. That resulting variation is the Maximum Rate and it is largely because of gravity’s effect on the balance wheel – the oscillator in the regulating organ of the movement.
YEMA’s in-house movements Maximum Rate is in the range of -/+ 25 s/d.
Generally, a watch will become less accurate as it nears the end of its power reserve, which is why watchmakers test watches within a narrow window of time, between 10 minutes and 60 minutes of full power in the case of YEMA, since an automatic caliber is generally assumed to always be at or near full power, at least while being worn.
Learn how to proceed to measure your YEMA watch's Daily Rate properly:
When a mechanical watch is removed for the night, it is best to place it dial up or dial down to keep accurate time. When a watch is placed in long-term storage, the position doesn’t matter as the watch will eventually stop running once the mainspring runs down.
When the watch on a bracelet or with a folding clasp is laid on its side in a vertical position, the surface contact area of both pivots of the balance wheel is much greater since both pivots turning against the wall of the bearings.
WHAT IF MY WATCH RUNS OUTSIDE MAXIMUM RATE?
The most common causes for a mechanical watch to run faster than the Maximum Rate specs are magnetism and/or shocks.
It’s quite common for watches to become magnetized, due to our frequent proximity to magnetic fields, unbeknownst to us. Magnets are everywhere, from speakers to mobile devices. Magnetized watches will generally run fast by several minutes per day. Before trying to determine if your watch is running accurately or not, make sure it’s not magnetized. Holding a compass near your watch is a quick and easy way to tell.
If it is magnetized, getting it demagnetized is quite easy to do, either using a Degausser machine (several available online for as little as $10), having a local watchmaker do it (typically a complimentary service), or simply returning it back to YEMA's workshops.
Shocks have long been the enemy of mechanical movements, as even a simple blow to a timepiece from smacking one’s arm against a table can be enough to cause damage to the movement, shocks can affect the amplitude of the balance wheel, the hairspring, and the poise of the balance. All these are inextricably linked and must be adjusted just right in order for a watch to keep a good Daily Rate.
In all cases, whenever your YEMA watch runs faster than its -/+ 25 s/d tolerance (ie the Maximum Rate) is best to contact our Customer Service so as to schedule a full re-calibration by our watchmakers.