Watch glossary: S.
SAPPHLEX CRYSTAL
Seiko's trademarked name for a fusion of sapphire and mineral glass crystals
SCALE
Graduation on a measuring instrument, showing the divisions of a whole of values, especially on a dial, bezel. The scales mostly used in horology are related to the following measuring devices: tachometer (indicating the average speed), telemeter (indicating the distance of a simultaneously luminous and acoustic source, e.g. a cannon-shot or a thunder and related lightning), pulsometer (to calculate the total number of heartbeats per minute by counting only a certain quantity of them). For all of these scales, measuring starts at the beginning of the event concerned and stops at its end; the reading refers directly to the chronograph second hand, without requiring further calculations.
SCREW BALANCE
Before the invention of the perfectly weighted balance by use of a smooth ring, balances were fitted with weighted screws to get the exact impetus desired. Today a screw balance is a subtle sign of quality in a movement due to its costly construction.
SCREW-DOWN LOCKING CROWN
A crown which aids water resistance by sealing the crown against the case. The seal is achieved by the matching of a threaded pipe on the case with the crown's internal threads and gasketing while twisting the crown to lock it into place.
SECOND TIME-ZONE INDICATOR
An additional dial that can be set to the time in another time zone. It lets the wearer keep track of local time and the time in another country simultaneously. See also GMT and world time.
SECTOR, see rotor.
SELF-WINDING, see automatic.
SHOCKPROOF or SHOCK-RESISTANT
Watches provided with shock-absorber systems (e.g. Incabloc) help prevent damage from shocks to the balance pivots. Thanks to a retaining spring system, it assures an elastic play of both jewels, thus absorbing the movements of the balance-staff pivots when the watch receives strong shocks. The return to the previous position is due to the return effect of the spring. If such a system is lacking, the shock forces exert an impact on the balance-staff pivots, often causing bending or even breakage.
SIDEREAL TIME
The conventional time standard refers to the sidereal year (defined in terms of an average of 365.25636 days) considered to be perfectly regular until very recently, but - even though this is not true - the difference is so slight that it is virtually neglected. As a unit of time, the sidereal day is used mainly by astronomers to define the interval between two upper transits of the vernal point in the plane of the meridian.
SKELETON, SKELETONIZED
Watches whose bridges and pillar-plates are cut out in a decorative manner, thus revealing all the parts of the movement.
SLIDE
Part of a mechanism moving with friction on a slide-bar or guide.
SMALL SECOND
Time display in which the second hand is placed in a small subdial.
SNAILING
Decoration with a spiral pattern, mainly used on the barrel wheel or on big-sized full wheels.
SOLAR POWERED
A watch that uses solar energy (from any light source) to power the quartz movement. Citizen call their solar powered watches "Eco-Drive".
SOLAR TIME
The time standard referred to the relative motion of the Earth and the Sun governing the length of day and night. The true solar day is the period measured after the Sun appears again in the same position from our point of observation. Due to the non-uniform rotation of the Earth around the Sun, this measure is not regular. As an invariable measure unit, the mean solar day corresponds to the average duration of all the days of the year.
SOLSTICE
The time when the sun is farthest from the equator, i.e. on June 21st (Summer solstice) and December 21st (Winter solstice).
SONNERIE (EN PASSANT)
Function consisting of an acoustic sound, obtained by a striking work made up of two hammers striking gongs (s.) at set hours, quarter- and half-hours. Some devices can emit a chime (with three or even four hammers and gongs). By a slide or an additional pusher it is possible to exclude the sonnerie device and to select a so-called grande sonnerie.
SPLIT-SECOND CHRONOGRAPH
Chronographs with split-second mechanisms are particularly useful for timing simultaneous phenomena which begin at the same time, but end at different times, such as sporting events in which several competitors are taking part. In chronographs of this type, an additional hand is superimposed on the chronograph hand. Pressure on the pusher starts both hands, which remain superimposed as long as the split-second mechanism is not blocked. This is achieved when the split-second hand is stopped while the chronograph hand continues to move. After recording, the same pusher is pressed a second time, releasing the split-second hand, which instantly joins the still-moving chronograph hand, synchronizing with it, and is thus ready for another recording. Pressure on the return pusher brings the hands back to zero simultaneously, provided the split-second hand is not blocked. Pressure on the split pusher releases the split-second hand, which instantly joins the chronograph hand if the split-second hand happens to be blocked.
STAFF or STEM, see arbor.
STOPWATCH
A watch with a seconds hand that measures intervals of time. When a stopwatch is incorporated into a standard watch, both the stopwatch function and the timepiece are referred to as a chronograph.
STOPWORK
Traditional device (now obsolete) provided with a finger piece fixed to the barrel arbor and a small wheel in the shape of a Maltese cross mounted on the barrel cover, limiting the extent to which the barrel can be wound.
STRIKING WORK, see sonnerie and repeater.
SUBDIAL, see also zone.
A small dial on a watch face used for any of several purposes, such as keeping track of elapsed minutes or hours on a chronograph or indicating the date.
SUPER-LUMINOVA, see luminescent.
SWEEP SECOND HAND
A center second hand, i.e. a second hand mounted on the center of the main dial.
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