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Mean daily rate / Normal usage accuracy
The accuracy of a mechanical watch varies depending on many things,
such as the amount the spring is wound, temperature, or resting position of the watch.
Thus, to show the accuracy of a mechanical watch evenly, not depending on the environment,
loss/gain of a mechanical watch is measured
before the movements of the watch are put in the case,
under controlled conditions, with many days of tests.
And the measured rate is called “mean daily rate”.
In both the ISO3159 and the Grand Seiko Standard
*
,
the standard rate is mean daily rate.
* “THE GRAND SEIKO STANDARD” P. 35
This rate is the data measured in an environment that is artificially controlled,
in order to fairly evaluate/show the abilities of mechanical watches without being influenced by
environmental changes.
So it is different from “normal usage accuracy”
when you are actually wearing the watch.
The accuracy of a mechanical watch varies delicately day by day, depending on the
environment.
This is like a living thing,
one of the charms that a mechanical watch has.
Normal usage accuracy should be from –1 second/day to +10 seconds (–1 to +8 seconds
for Cal. 9S86 and 9S85, –5 to +10 seconds for Cal. 9S27) /day. If the average of the daily
rates exceeds this level, we recommend adjusting the watch accordingly.
To adjust the accuracy as accurately as possible, information such as the rate of loss/gain
of your watch and how you use it, are very important. Please let us know the following when
you ask for adjustment of your watch by our service center.
(1) The average daily loss/gain rates for one week to ten days
Ex. an average of +11 seconds
(2) Approximate hours of wearing the watch in one day in the above period
Ex. Approximately 10 hours
(3) The resting position of the watch while you don’t wear it
Ex. Horizontal - Dial up
Vertical - the crown up
4
INTRODUCTION
-About mechanical watch-
Characteristics of a mechanical watch
For lifelong use of your mechanical watch rule No.1
Wind the mainspring of your mechanical watch at a fixed time.
As there are rules for everything, there is a rule for
winding the spring.
You have not heard this before?
Please keep it in mind.
The mainspring - the source of energy for a
mechanical watch.
When it is fully wound, it can supply the most
stable energy to every part of the watch
movement, and the accuracy of the watch
becomes most stable.
Power the
mainspring
supplies
High
Low
Duration from a fully wound state
Even if your watch is a self-winding type, when you
feel the accuracy is not stable, turn the crown to
wind the mainspring further.
If you work at a desk, etc., and do not move
enough, the spring will not be wound sufficiently.
If your watch is a hand-winding mechanical type,
turn the crown every day, at a fixed time to wind
the mainspring sufficiently.
To use the watch with better accuracy, wind the
mainspring every day, at a fixed time.
Please keep to this rule as best as possible.
For instance,
You may make it a rule to wind the spring
When you wake up, or at lunchtime.
For lifelong use of your mechanical watch rule No.2
Place your watch correctly, like this.
Half of one day, twenty-four hours,
when you do not wear your watch.
The accuracy while you do not wear the watch is included in “normal
usage accuracy”.
The mechanical watch that you take off.
Which position should the watch be put in?
The loss/gain of a mechanical watch
depends on the resting position of the watch.
In one position, the watch tends to gain, in another position, it doesn’t.
For instance, while you are sleeping at night,
when you do not wear your watch,
put the watch in various positions for seven to eight hours, such as
placing it with its face turned up,
or with the crown up, to find the best resting position for the watch for
reducing the loss/gain that occurs while you are wearing your watch.
Horizontal-
dial up
Vertical-
3 o’clock
5
INTRODUCTION
-About mechanical watch-
For lifelong use of your mechanical watch
English
Содержание 9S27
Страница 1: ...Printed in Japan BSJ9SCCH 2101...