Ming
Theins Horological Dictionary
October 2003 v1.3
Edited by John Davis
A
Acrylic crystal
Watch crystal made of a plastic substance. It is shatter and shock resistant,
but prone to scratches due to its softness. Fortunately it is also polishable
using various polishing compounds.
Adjustment The art of making changes to the escapement of a
watch to minimise the timing errors associated with different positions,
temperatures and states of wind. It
can involve adjustments to the hairspring, the curb pins, the balance, the
balance pivots and the escapement but may even include adjustments or
corrections within the power train or barrel itself. See also Rate, Poise,
Timing
Alarm A chime or gong which triggers at a set time. See also
Hammer
All or nothing piece
The lever in a minute repeater or sonnerie en passant which arms the system with
sufficient energy to strike the hours, quarters and minutes. The repeater will
only trigger if the slide is pushed all the way, thus arming the all or nothing
piece. See also, Minute Repeater
Amplitude Amplitude is the measure in degrees of the maximum
angular displacement of the balance from its resting position.
See also Balance
Anglage The bevelling and polishing of an edge of a part (bridge,
wheel, lever, etc). See also Finishing, Chamfer
Annual calendar
A calendar which is programmed to take into account the different lengths of the
months over a one year cycle, but must be corrected for 1st March.
Usually features date and month; may also feature day of the week and moonphase.
See also Perpetual Calendar, Moonphase, Synodic Moonphase, Secular Calendar,
Guichet
Antimagnetic A watch whose running rate is not affected by
magnetic fields up to a certain strength x is determined to be antimagnetic to
this level. See also Dust Cover
Antireflective coating
An optical multilayer coating on the inside, outside or both sides of a crystal
in order to reduce reflections and increase visibility of the dial or movement.
See also
Arbor The central pivot or axle running through a wheel.
Usually used in reference to the barrel arbor.. See also Pivot, Barrel,
Mainspring
Astronomic indications
Any calendar based function which performs astronomic indications such as signs
of the zodiac, star charts, planetariums, etc. See also Perpetual Calendar,
Planetarium
Atmosphere A measure of the pressure to which a watch is water
resistant. One atmosphere is the pressure at sea level; it is also approximately
equivalent to one bar, or ten meters of static depth in water. See also Bar,
Water Resistance
Automatic winding
A mechanical watch which winds itself. This is almost always done by means of an
oscillating weight whose rotary motion is reduced through a series of gears;
however there have been innovative mechanisms in the past which have used other
methods such as changes in temperature, or expanding lugs, etc. See also Rotor,
Reduction Gear, Bidirectional gear
Automaton A miniature robot within a watch whose movement is
animated. Usually these operate in conjunction with repeaters or sonneries, and
they are usually depicting erotic scenes. However, automatons which could be
operated on demand were popular in the 17th and 18th centuries. See also Minute
Repeater, Repeater, Sonnerie, Jacquemart
Balance The regulating organ of a watch, which oscillates at the
frequency of the movement. During its swing, it locks and unlocks and receives
impulse from the gear train of the watch via the escape wheel and pallet lever,
thereby regulating the rate of unwinding of the mainspring. The balance
oscillates by means of interaction with a concentric spiral hairspring. The
timing rate of a watch may be altered by adjustment of the inertia of the
balance or effective length of the hairspring, thereby altering the frequency of
the balance. See also Escapement, Coaxial Escapement, Pallet Lever, Jewel,
Frequency, Rate, Adjustment, Position, Poise, Balance Cock, Balance Staff,
Hairspring, Inertia, Variable Inertia Balance, Free Sprung Balance
Balance cock The one-sided bridge which holds the balance in
place. See also Balance, Tourbillon, Pivot.
Balance staff The
arbor to which the balance, impulse jewel, roller table and hairspring collet
are attached. See also Balance, Roller Table, Hairspring, Balance Cock
Ball bearing A small highly smooth and polished sphere which sits
together with other ball bearings in a ball race, used to reduce rotational
friction. See also Bearing, Jewel
Ball race A bearing type which reduces the friction of a
rotating shaft by converting shear friction to rolling friction. See also Ball
Bearing, Pinion
Band The piece of material used to attach the watch to the wrist.
Length is adjustable and the word band typically refers to a strap made of
leather or some other pliable material. See also Strap, Bracelet, Springbar, SEL,
Deployant clasp, Butterfly clasp
Bar A measure of atmospheric pressure, and water resistance of a
watch. One bar is approximately equal to one atmosphere, which is equal to ten
meters of static water depth. See also Atmosphere, Water Resistance
Barrel The housing for the mainspring. One end of the mainspring is
attached to the barrel arbor, and the other end to some point around its
circumference. Upon winding, the spring coils up, storing energy; on unwinding,
the barrel itself unwinds and provides torque to the rest of the train. See also
Mainspring, Arbor, Train, Click
Baseplate The bottom plate of a watch to which the timing train
will be attached. Depending on the complexity and size of the watch, some
complications may be housed directly on the baseplate also, along with the
automatic wining system. See also
Mainplate
Bead blasting A method of finishing whereby a totally
non-directional matte finish is achieved by blasting the item with a high
pressure jet of fine grained objects. See also Finishing
Beat Error Beat error is the lack of symmetry between the
tick and tock cycles of the escapement. See also Timing, Rate,
Balance, Frequency
Bezel The outer circumference of a watch when viewed from the top,
i.e. the part surrounding the crystal and dial. It may have a scale marked on it
used to make extra measurements using the second hand, typically in conjunction
with a chronograph. See also
Bidirectional rocker
A switching gear used in automatic winding mechanisms (in order to wind the
barrel when the rotor turns in either direction). See also Automatic, Power
Reserve, Rotor
Bidirectional winding
An automatic winding system which winds the mainspring irrespective of the
direction of rotation of the rotor. See also Automatic, Power Reserve, Rotor
Big date A date indication mechanism using sets of digits which
allows the date to be displayed much larger than conventional dates which must
fit the entire 1-31 in the space around the dial.
Bimetallic balance
A balance which is made of two materials which act in concert to compensate for
changes in the hairspring due to variations in temperature. See also Isochronism,
Balance, Timing, Rate
Black polishing
A part is said to be black polished when it appears black under certain angles,
whilst being perfectly mirrored from others. See also Finishing
Blue gold An artificial colour of gold made by alloying gold
with copper and cobalt. See also Gold
Blueing A part may be blued heat blued by heating it in a flame to a
certain temperature and then slow cooling or quenching it in liquid, or blued
chemically using dyes. This rapid cooling causes a thin uniform layer of
material (magnetite in the case of steel parts) to form on the surface, which is
usually blue in colour. The colour obtained in heat blueing depends on the
temperature to which the part is heated. Blueing
also tempers the steel which ensures that the steel will be resilient but
neither too soft or brittle for watchmaking applications.
See also Screws
Bombe Curved, or twisted. See also
Bracelet A metal strap. See also Strap, Band, Deployant Clasp,
Butterfly Clasp
Breguet overcoil
An overcoil hairspring has the last coil (the terminal curve) raised above and
parallel to the others. Often referred to as Breguet or Phillip's overcoils for
their pioneering work in the field, they are designed to improve positional
performance and isochronism. See also Overcoil, Hairspring, Balance, Collet,
Stud, Timing, Adjustment, Rate, Terminal curve
Bridle An extra piece attached to the outer part of the mainspring.
In handwinding watches this is fixed; in automatic watches the bridle is usually
slippable in order to serve as protection against overwinding. See also Barrel,
Mainspring
Brushing A method of finishing whereby an abrasive compound is
applied in one direction only, to produce a series of very close parallel marks
on the surface of the part. See also Finishing, Graining
Bullhead Chronograph layout where the pushers are at 11 and
Bumper automatic
A type of automatic winding system where the rotor isnt free to turn in a
full circle, but rather is bumped back by springs at either end of its arc.
Found usually in early automatic watches. See Automatic winding, Microrotor,
Rotor
Butterfly clasp
A type of strap or bracelet fastening that has two sides to be fastened
independently of each other. These are designed to sit more centrally (and thus
more comfortably) on the wrist than single fold clasps. See also Deployant Clasp
Calendar Any mechanism that shows the time in greater units than 24
hours. See also Perpetual Calendar, Annual Calendar, Big Date, Guichet
Caoutochouc French word for natural rubber. See also Strap,
Silicone
Canon pinion A friction fit gear or pinion that acts as a clutch
in order to permit hand setting of the time as well as driving of the hands via
the motion works. The hands are
attached to the dial side of the canon pinion. See also Train, Keyless Works
Cap jewel A jewel bearing where a conical piviot passes through
a hole jewel and rests on a closed jewel at either end. This type of jewel is
usually used on the end of balance staffs and escape wheel pivots. It results in
better oil retention than a standard jewel as it is effectively sealed, and also
less friction in horizontal positions. See also Jewel, Chaton, Bearing, Pivot
Carillon An acoustic striking complication which uses more than two
gongs. See also Minute Repeater, Grand et Petite Sonnerie, Sonnerie
Caroussel tourbillon
A tourbillon whose cage pivot does not share the same axis as the balance staff;
the advantages of this decentralized arrangement are that a standard geometry
Swiss Lever escapement may be used (a proper tourbillon requires a specially
designed pallet fork), and the escapement is much flatter as the balance wheel
does not have to overlap the escape wheel. The disadvantage is that the balance
is much smaller than in a traditional tourbillon, compromising potential timing
results somewhat. See also Tourbillon, Decentralized, Pallet Fork, Swiss Lever
Escapement, Escapement, Balance, Pivot, Balance Staff
Case The part of the watch which houses and completely encloses
the movement.
Case back The removable back part of the watch case.
Case band The sides of the watch case, i.e. the main body.
Centre wheel The wheel which is driven by the barrel, rotating
once per hour. The cannon pinion and minute hands also rest on this wheel.
Traditionally resided in the centre of the watch, but in the pursuit for
central seconds and more space within the watch, it has been relegated from its
implied position. See also Train
Central seconds
A seconds indication whose hand has the axis running through the centre of the
dial. See also Direct Seconds, Indirect Seconds, Fourth Wheel, Sweep Seconds
Central tourbillon
A tourbillon with the cage and balance axis centred through the centre of the
dial. Very difficult to achieve as this requires some cunning tricks to have
central hands as well. See also Tourbillon
Chamfer Anglage, or a bevel on a part. See also Finishing
Chaton A (usually) precious metal setting for a jewel bearing
enabling it to be replaced in future. Chatons may be friction fit or held in by
screws. See also Jewel
Chronograph A device for measuring elapsed time, in addition to
normal timekeeping functions. All chronographs can be started at zero, stopped
when the desired timing period has elapsed, and finally reset to zero. The
chronograph totalizers are usually driven off an extended fourth wheel pinion.
See also Fourth Wheel, Lever, Column Wheel, Coulisse, Reset Lever
Chronometer A movement which has been certified by the COSC for
certain standards of accuracy during a 15 day test in different positions and
temperatures. See also COSC
Cintree curvex
Type of case somewhere between Tortue and Tonneau. Popularized by Franck Muller.
It is said that this type of case has no straight edges, but Im not sure
about this.
Click A sprung ratchet used to stop the barrel from unwinding in
the undesired direction. The clicks may typically be sliding (traditional German
style) or rotating (Swiss style). See also Barrel
Coaxial Escapement
A new type of escapement developed by Dr. George Daniels which almost entirely
separates the balance impulse from the locking and unlocking functions of the
escape wheel. The design reduces sliding friction in the escapement, which is
the main source of amplitude loss and poor timing. See also Escapement
Collet The clip around the balance staff which is used to attach
one end of the hairspring. See also Balance Staff, Flange, Hairspring, Balance
Column wheel A two level tooth wheel used to coordinate the
functions of a chronograph. The upper level has a series of alternating raised
and lowered portions (columns) which admit or block the chronograph levers; this
assembly is rotated by means of a ratchet linked to the pushers, thus
controlling the operation of the chronograph. See also Chronograph, Lever
Compass bezel A bezel which is marked 0-360 degrees. See also Bezel
Compass function
A watch may be used as a compass; point the direction between the hour hand and
Complication Any additional function performed by a watch other
than basic timekeeping. See also Chronograph, Calendar, Perpetual Calendar,
Annual Calendar, Foudroyante, Rattrapante, Sonnerie, Minute Repeater, Secular
Calendar,
Complication plate A
removable module not integrated into the base movement which houses a
complication. See also Modular construction, Plate
Corundum The name for pure sapphire crystal almost never found
naturally but used commonly in watchmaking for jewel bearings and crystals. See
also Sapphire, Sapphire Crystal, Jewel, Bearing,
COSC Controle Official Suisse de Chronometers the
organization which tests watches and issues chronometer certificates. The tests
involve timing in different positions, temperatures and various combinations of
the two. See also Chronometer, Rate,
Adjustment, Timing
Cotes fausees Another striping technique similar to Cotes de Geneve.
Less spectacular in appearance but more difficult to create; traditionally
achieved using ivory polishing tools, but seldom see in modern movements. See
also Finishing
Cotes du soliel
Concentric circular stripes radiating from a single point; or radial stripes
originating from a single point. Both are performed using the same methods and
techniques as Cotes de Geneve. See also Finishing
Coulisse and lever
A method of coordinating chronograph functions where an irregular cam is used,
rather than a column wheel. Less traditional and simpler to manufacture as the
coulisse (switching cam) can be stamped and welded together rather than
meticulously cut as with a column wheel. See also Chronograph
Countersink A method of fitting a screw whereby a hole in the
plate is cut to accommodate the head of the screw. The end result is that the
head of the screw is set flush with the plate when the screw is tightened. Also
the bevel around any circular hole. See also Screw, Chamfer
Crown The wheel which is outside the watch, manipulated by the
user in order to wind the watch and set the time and any other functions. See
also Crown Stem, Crown Guard
Crown guard Method of protecting the crown from damage; includes
everything from simple shoulders in the case to elaborate locking mechanisms (a
la Panerai.) See also Crown
Crown stem Shaft to which the crown is attached. See also Crown
Crown wheel The intermediate horizontal transfer wheel between
the winding pinion and the ratchet wheel. Sometimes also used to describe the
castle wheel. See also Crown, Castle
Wheel, Handwinding
Curb pins Parallel pins used to interact with the outer coil of
the hairspring. Their position is adjustable so that the effective length of the
hairspring and thus the timing of the watch is also adjustable. Note that in
free sprung watches there is no curb pin as the hairspring length is not used to
alter the rate of the watch. See also Hairspring, Balance, Timing, Rate,
Adjustment, Free Sprung Balance
Cyclops Magnifying crystal over the date. May be external (Rolex) or
internal (Panerai). External cyclopses are attached by means of transparent
crystal cement and are not a single piece with the rest of the crystal. See also
Crystal, Magnifier
Dead seconds A second hand which jumps in the same fashion as a
quartz watch.
Decentralized Off centre.
Deployant clasp
A folding buckle used to prolong the life of a leather of fabric strap, and also
to provide added security when putting on or taking off the watch. See also
Strap, Butterfly Clasp, Bracelet
Deployment clasp
See Deployant Clasp
Detent Term used to describe when a part is held in one particular
position, usually by means of carefully profiled levers or springs. It is also
the name for set lever or pull out piece. See
also Spring, Lever
Dog Leg A kink in the stud carrier end of the hairspring, originally
used to keep the outer coils of the hairspring from falling foul of the curb
pins. Recently discovered that
performance gains can be found providing the correct geometry is used.
See also Hairspring, Curb Pin
Doming Curving a watch crystal in order to increase strength and
reduce reflections. See also
Double assembly
A process performed by some manufactures and watchmakers in which the
undecorated movement is assembled, tested and adjusted, and then disassembled in
order to apply the final finishing. The movement is then reassembled and
regulated. See also Finishing, Adjustment, Regulation
Dial side The side of the movement under the dial, usually
housing the canon pinion, dial train and keyless works. See also Canon Pinion,
Keyless Works
Differential gear
A gearing system in which clockwise or anticlockwise rotation is converted to
rotation in one direction only, used particularly in power reserve indications,
and automatic winding reduction gearing. See also Automatic, Gear, Power
Reserve, Resonance
Direct seconds
A movement in which the seconds indication is driven directly off the fourth
wheel, i.e. it is in the flow of power between the barrel and the escape wheel.
See also Indirect Seconds, Fourth Wheel
Display back A transparent back fitted to the watch so that the
movement may be appreciated. See also
Diving bezel A bezel which rotates anticlockwise and marked to 60
minutes. This is used to time events. The bezel itself detents to minute, or in
some cases, half minute, increments. See also Bezel
Dust cover Older watches used to be fitted with two backs in
order to minimize dust entering the movement. With modern watches and proper
sealing, the dust cover is usually used as either a spacer or antimagnetic
shield for the movement. See also Half Hunter
Dynamograph A complication used to measure the instantaneous
torque of the mainspring barrel. This is accomplished by the use of springs and
levers which determine the tension in the mainspring and then convert it to
motion of a pointer on a scale. See also Torque, Power Reserve, Power Reserve
Indicator
E6B flight computer bezel
A type of slide rule bezel which allows the calculation of distances, times,
fuel consumptions, etc. Use by pilots and typically found on chronographs. See
also Bezel
Electroplating
See Plating
Enamel A method of finishing in which porcelain is applied to the
surface of a metal dial and then fired in a kiln.
True enamel is made of vitreous porcelain, although in modern times the
name has come to be confused with certain types of paint.
The colour of enamel is unaffected by age or exposure to ultraviolet
light, however the disadvantages are that they are very fragile, prone to
cracking, and also comparatively expensive to produce. See also Dial
End piece The part of the bracelet which attaches the bracelet
proper to the lugs of the watch. Also known as an end link.
See also Bracelet
Endshake The vertical play of any pivot in its bearing.
It is necessary for proper function and only becomes a problem if the
play is excessive. See Bearing, Pivot, Jewel, Chaton
Endstone The name given to a cap jewel, specifically the cap jewel on
the balance. May be ruby, sapphire, or rarely, diamond. See also Jewel, Cap
Jewel, Ruby, Sapphire, Diamond
Engine turning
See Guilloche
Engraving Either pragmatic (make and model) or decorative
(elaborate scenes and logos, for instance) method of decoration. Can be used
on all parts of a watch; typically employed on the movement itself when it is
skeletonized, and sometimes also on the dial. See also Guilloche,
Skeletonization
Epicycloid teeth
Gear tooth profile following a circular trajectory on the outside of another
larger circle, which maximises power transfer and minimises friction. Best
used with hypocycloid (inverse pattern) pinions for maximum efficiency. Modern
watches typically use a modified profile somewhere between parabaloid and
epicycloid. See also Gear, Hypocycloid teeth
Equation of time
A complication which measures the time difference between Earth time and mean
solar time effectively the deviation of the Earths orbit from a perfect
circle. This is less than 15 minutes per year and cancels out on opposite legs
of the orbit, as it is a symmetrical ellipse. The complication is achieved by
means of a lever reading off a profiled cam onto a calibrated scale. The cam
rotates once per year. See also Calendar, Complication
Escapement The mechanism by which the energy supplied by the
train is supplied to the regulating organ, almost always a balance. See also
Swiss Lever Escapement, Balance, Pallet Fork, Coaxial Escapement, Rate, Timing,
Hairspring, Adjustment, Curb Pins, Overcoil, Breguet Overcoil, Hairspring,
Philips Overcoil, Stud, Balance Staff, Free Sprung Balance, Variable Inertia
Balance, Inertia
Escape wheel The wheel with a tooth profile that allows it to be
locked and unlocked alternately by the pallet fork, allowing the mainspring to
unwind by one escape wheel tooth at a time. See also Gear, Escapement, Pallet
Fork, Balance
Fast Beat A movement which has a frequency of 4 Hz or higher,
i.e. 28800bph or more. See also Frequency
Finishing Any method of finishing a part, be it decorative or
functional. See also Guilloche, Anglage, Perlage, Polishing, Black Polishing,
Engraving, Engine Turning
Five minute repeater
A complication which chimes the time on demand in hour and five minute
increments on two gongs. See also Chime, Gong, Hammer, Repeater, Minute
Repeater, Carillon, Sonnerie
Flange A concentric protuberance on a part.
Floating lugs Lugs attached by means of a pivot to the case,
allowing them to move. See also Strap, Band, Bracelet, Lugs
Flyback A chronograph that can be reset and restarted without
stopping, achieved by a single push of a button. This term is often confused
with retrograde hands and split second chronographs, because they fly back
to their original positions. See also Chronograph
Flying seconds
A chronograph in which there is a registering measuring up to one second, in
increments determined by the frequency of the escapement usually Ό or 1/8
second. Usually an additional barrel is required to run this indication due to
the high power consumption required. It is also recommended that it is not run
for a long period of time because the friction will cause the bearings to heat
up and cause the oil to evaporate prematurely. Also
known as Lightning Seconds and Foudroyante.
See also Foudroyante, Chronograph
Flying tourbillon
A tourbillon whose cage is attached to the movement on one side only, i.e.
having only one pivot. See also Tourbillon, Pivot, Ball Race
Folding clasp see Deployant Clasp
Form movement A movement which is made to fit the shape of the
case. This term usually applies to non-round movements only.
Foudroyante The proper name for Flying Seconds.
Fourth wheel The last wheel in the timing train before the escape
wheel. This wheel rotates once per minute, and the second hand is usually driven
off it. Also known as a seconds wheel. See
also Direct Seconds, Indirect Seconds, Chronograph
Free Sprung See Free Sprung Balance
Free Sprung Balance
A balance which is free sprung is regulated by change in inertia (by shifting
masses on the balance) rather than change in the effective length of the
hairspring. This is more likely to deliver a more stable rate than a regular
balance, and the movable weights on the balance may also be used to adjust
poise. See also Hairspring, Balance, Gyromax, Poise, Rate, Adjustment, Timing,
Inertia
Frequency The rate at which the balance oscillates (i.e. the
number of times the balance will swing per second). Typical frequencies are slow
beat (18000bph/2.5Hz, 21600bph/3Hz), fast beat (28,800bph/4Hz) and very fast
beat (36000bph/5Hz) and quartz (~32627Hz). A faster frequency will be better for
producing more stable timing, but will also have higher power requirements and
will produce more wear on the parts in the movement. See also Escapement,
Resonance, Fast Beat, Slow Beat, Power Reserve
Gasket Rubber seal fitted to the profile of the case back and
crystal, lubricated with silicone grease and used to stop moisture and dust
incursion into the movement. The higher the water resistance required, the more
heavy duty the gasket used. Proper lubrication and regular checks are required
to ensure proper water resistance. See O-ring, Water Resistance
Gear A wheel with teeth around its periphery used for
transferring rotational motion from one axis to another. Different sized gears
can be mated together to alter the rotational speed of the axis to which the
motion is being transferred. See also Epicycloid teeth, Hypocycloid teeth, Wolf
Teeth, Straight cut teeth, Pinion
1A The workmanship of all parts and functions must meet the
Geneva Seal requirements;
1B Steel parts must be anglaged and surfaces polished. Screw
head have to be polished with chamfered slots and rims.
2 All movement train pivots must be jewelled, and half
frosted with polished sinks on the bridge side.
3 The balance spring should be pinned in a grooved plate with
a stud having a rounded collar and cap. Mobile studs are allowed
4 Split or fitted indexes are allowed with a holding system
except in extra thin calibres where the holding system is not required.
5 Variable inertia balances are permitted providing that they
comply with 1A and 1B.
6 The wheels of the going train have to be chamfered above
and below and have a polished sink. In wheels 0.15mm thick or less, a single
chamfer is permitted on the bridge side.
7 In wheel assemblies, the pivot shanks and faces of the
pinion leaves have to be polished.
8 The escape wheel has to be light, less than 0.16mm thick in
large calibres and 0.13mm in calibres less than 18mm, and its locking faces have
to be polished.
9 Adjustable banking for the pallet fork is not permitted.
10 Shock proofing is permissible.
11 The ratchet wheel and crown wheel should be finished
according to registered patterns.
12 Wire springs are not permissible.
See also Pointcon de Geneve
Gilding Applying a golden finish to a surface, usually to highlight
engraving or other details such as jewel or screw chamfers. See Gold, Finishing
Glashutte stripes
Identical to Cotes de Geneve, but this name is given to stripes decoration
performed on watches made in Glashutte.
Glycdur An alloy of beryllium and copper which is used widely in
watchmaking for balances and wheels due to its extremely stability, strength
and resistance to corrosion and magnetic fields. Heat tempering, and also black
polishing, are possible. See Gear,
Train, Balance
GMT See Greenwich Mean Time
Going train The series of gears and pinions which are used in the
timekeeping train, including the barrel. See Train, Gear, Pinion, Escapement,
Barrel
Gold A naturally occurring metal, with density 19.7 g/cc, very
malleable (it can be beaten to a sheet 1/1000th of a millimetre thick) and
extremely resistant to corrosion. The colour of the unalloyed pure metal is a
rich yellow. Various colours and grades of purity are available; these are
achieved by alloying with other metals. The typical grade used in watchmaking is
18 karat or 750 parts per thousand, which is considered to be a good compromise
between strength and corrosion resistance. The more common colours available
are:
1) red/rose gold (alloyed with copper and nickel),
2) white gold (alloyed with rhodium, sometimes also plated
with palladium or a platinum family metal for surface treatment),
3) yellow gold (pure or alloyed with copper, nickel, tin and
zinc),
4) blue gold (rare; alloyed with copper and cobalt),
5) green gold (used by Rodger Dubuis, not sure what its
alloyed with),
6) grey gold (alloyed with vanadium and tin).
In terms of hardness, white gold ranks is the hardest,
followed by yellow and then rose gold. White
gold is comparable to some stainless steels in hardness.
Gong A part which, when struck by a hammer, produces some audible
effect. This may take the form of a bell shaped movement cover (in most alarm
movements), or a concentric chime which runs around the periphery of the
movement (common in sonneries, minute repeaters, and some very high grade
alarms.) See also Sonnerie, Minute Repeater, Chime, Hammer
Graining Application of a slightly coarser version of brushing. See
Brushing, Finishing
Grand et petit sonnerie
A watch which strikes the hours and quarters (grand sonnerie) on the quarters
and hours, or a watch which strikes the hours on the hour and quarters on the
quarter (petit sonnerie). Usually combined with minute repeater functions, and
there is also a switch to turn the chime off completely. The sonnerie is
triggered by a piece which rotates once per quarter and then trips the repeater
mechanism on the quarters or hours. Since the sonnerie is automatically
activated, there is also a second barrel to power the strike train in the watch.
See Sonnerie, Minute Repeater, Strike Train, Hammer, Gong, Chime
Greenwich Mean Time
The reference to which all other time zones are set if GMT is 12.00, then
the other time zones extend in one hour increments to + or 12 hours on
either side. The Greenwich Meridian determines the boundary of the first time
zone.
Guichet A window cut in the dial to allow the viewing of an
indication displayed underneath, usually some sort of calendar function. The
display occupies the whole of the guichet and then changes by means of rotating
a wheel underneath with all the possible indications on it. Also known a an
aperture. See Calendar, Date, Big
Date
Guilloche A method of decoration which uses deep parallel and
intersecting grooves to leave a raised pattern on the surface of a part. Used
mostly on dials (Breguet, for example) and some automatic winding rotors.
Typically a soft metal such as gold or silver is used as it is easier to engage.
See Finishing, Engraving, Engine Turning
Gyromax The trade name of a variable inertia balance used by Patek
Philippe. A two armed balance is fitted with eight equally spaced eccentric rim
weights which can be rotated in opposing pairs to change the inertia of the
balance and thus the rate of the watch. It is also possible to change the poise
of the balance by moving the appropriate weights. See Free Sprung Balance,
Variable Inertia Balance, Hairspring, Poise, Adjustment, Rate
Hairspring A concentric spiral spring which is used to maintain
the oscillation of the balance. One end is attached to the balance staff, and
the other end is attached to the balance cock. This exerts a restoring force on
the balance once it is displaced from the neutral position, and thus causes the
balance to oscillate. Hairspring ends may be treated with a simple dog-leg, a
Philips overcoil, or a Breguet overcoil. It is possible to alter the rate of a
watch by means of changing the effective length of the hairspring. See also Free
Sprung Balance, Rate, Adjustment, Stud, Collet, Balance, Breguet Overcoil,
Philips Overcoil, Terminal curve, Overcoil
Half hunter A type of watch or pocket watch that has no cover
over the dial of the watch other than the crystal, and a double back.
Traditionally, this took the form of a crystal cover with an aperature to allow
time viewing on a pocket watch. See also Crystal, Display Back
Hallmark An embossed stamp issued by the regulatory authorities to
attest to the purity or origin of precious metals or gemstones. See also Gold,
Silver, Platinum
Hammer A percussion part, which when activated, hits a gong to
create an audible indication. Each gong has a single hammer, but there may be
several hammers in one watch if it is equipped with one or more gongs. See also
Chime, Alarm, Minute Repeater, Grand and Petit Sonnerie, and Carillon.
Hands The movable pointers on the dial of a watch which indicate
the time. The main hands are usually attached to the canon pinion and hour
wheel, and additional hands will be located on the ends of their own respective
pinions. Chronograph second hands are usually passed through the drilled out
canon pinion. See also Canon Pinion, Blueing, Chronograph
Handwinding The mainspring of the watch is wound manually through
the crown, i.e. there is no automatic winding system. See also Automatic
winding, Key, Keyless works
Heartpiece The cam attached to a chronograph totalizer pinion
which, when acted upon by the reset lever, causes the chronograph hand to reset
to the zero position. This is accomplished by having a profile such that the
reset lever always rests in the concavity of the heart cam. The standard
chronograph reset levers use a logarithmic profile spiral, but the split seconds
heartpiece uses a shallower spiral of Archimedes profile to minimise the load on
the movement when the chronograph hands are split. See also Chronograph, Reset
Lever, Pusher, Rattrapante, Split Second
Helium release valve (HRV)
Beyond a certain depth underwater, the pressure is sufficient to force the
helium molecule (the smallest molecule) through the case seals. This in itself
is not destructive, but when surfacing, if the helium is not released, it is
possible that the watch may explode if the pressure inside is high enough. To
counter this, a helium release valve may be used which allows helium to escape
whilst preserving the water resistance of the rest of the case.
Hesalite crystal
Omega trade name for Acrylic crystal. These were fitted to the original moon
watches. See also Acrylic Crystal, Crystal
Horology The proper name for watchmaking.
Hour Repeater An audible complication which chimes the time to the
nearest hour on a single gong. See also Repeater, Gong, Chime, Hammer
Hunter A type of pocket watch in which the dial and crystal are
covered by a hinged metal protector, along with a double hinged back (dust cover
and back). See also Half Hunter,
Hypocycloid teeth
Teeth with an inverse profile to epicycloid which are usually used on pinions to
maximise the efficiency of the power transfer between gears. The
profile is described by a circle rotating on the inside of another larger
circle. See also Gear, Epicycloid
Teeth, Pinion Leaves
Impulse The force received by the balance from the escape wheel
teeth and pallet fork during each part of its swing. See also Balance,
Escapement, Pallet Fork, Escape Wheel
Impulse jewel The jewel attached to the balance staff (usually on
the roller table, or alternatively on the balance arm itself for ultra-flat
escapements) which is pushed by the horns of the pallet fork, thus giving the
balance its impulse for oscillation. Also called a roller jewel.
See also Roller Table, Pallet Fork, Balance, Escapement
Incabloc A type of sprung jewel setting which allows the jewel to
move to protect the piviots when the watch is affected by some sort of shock.
See also Shockproofing, Parashock, Cap Jewel, Pivot, Chaton, KIF
Indirect seconds
A seconds indication mechanism which is out of the power flow (i.e. not directly
driven by the fourth wheel). These displays are prone to fluttering due to
insufficient torque through the intermediate gears. The problem can be corrected
by the use of a tension spring. See also Spring, Intermediate Wheel, Direct
Seconds, Fourth Wheel
Integrated lugs
Strap attachment points which are made from the same part as the main case
proper. They may be drilled out on the outside in order to facilitate easy
removal of the springbars. Also frequently used to describe a watch which has a
bracelet built into the case and cannot take a strap.
See also Springbar, Floating Lugs, Strap, Band, Bracelet
Intermediate crown position
The position between winding and time setting, usually used for calendar setting
in watches so equipped. See also Crown, Calendar, Perpetual Calendar, Annual
Calendar, Crown Stem
Intermediate wheel
A gear used to shift the axis of rotation from one point to another, or for
switching purposes (e.g. in chronographs), or for changing the speed of
rotation. See also Gear, Chronograph
Internal rotating bezel
A movable calibrated ring under the crystal, adjusted by an external crown.
Usually used as a diving bezel. See also Divers Bezel, Crown, Bezel
Inertia The resistance of a part to acceleration, be it for
rotational or linear motion. The higher the inertia, the grater the resistance.
Important note: this is a property of the weight of the part and its mass
distribution, and is NOT related to friction. Balances with large inertia are
desirable as they will be less likely to be perturbed from their oscillation. So
called variable mass or free sprung balances will be equipped with movable
weights in order to be able to change the inertia of the balance and thus the
natural period, changing the rate of the watch. See also Free Sprung Balance,
Poise, Variable Inertia Balance
Isochronism Isochronism is the tendency of a watch to keep a
consistent rate regardless of the amplitude of the balance.
Generally used to describe the watch's stability of rate over 24 hours of
unwinding, but some component of isochronism does relate to positions because of
the amplitude loss. See Regulation, Adjustment,
Rate, Timing, Poise
Jacquemart An automaton which operates in conjunction with some
sort of time-telling function, usually a repeater. See
also Minute Repeater, Carillon, Grand et Petite Sonnerie, Automaton, Sonnerie
Jewel A synthetic ruby bearing used at the end of pivots to reduce
rotational friction. Jewels must be properly oiled for optimum performance.
Originally, they were natural rubies set into replaceable gold settings; now
they are synthetic rubies and friction fitted directly into the plate. See also
Chaton, Bearing, Pivot
Jump hour A mechanism by which the hour is indicated in whole
increments, rather than a continuously moving hour hand. It may take the form of
a hand that jumps from one hour to the next, or a numerical display through a
window. This is accomplished by having a snail cam attached to the minute wheel.
A lever will advance the hour when tripped by the snail cam, and the hand or
indicator wheel is held in place by means of a detent spring. Occasionally the
hour pointer does not occupy the entire 360 degrees of the dial, and will jump
back from the 12 position to the 1 position once the time changes this is
known as a retrograde indication, and is accomplished by means of further racks,
levers and cams. See also Guichet, Retrograde, Detent, Snail Cam
Karussel A rotating escapement which is driven by the third wheel
pinion and rotates about a moving fourth wheel.
Key A removable device used to wind a pocket watch. Not used in
modern wristwatches since the advent of keyless works, which removes the
necessity of use of a separate removable key. Also
used to set pocket watches. See also
Keyless Works, Crown, Handwinding
Keyless works The system of springs and levers which switches the
castle wheel from the winding position to the time setting position (and
intermediate positions if applicable) when the crown is pulled out. Usually this
is mounted on the dial side of the baseplate. See also Castle Wheel, Crown,
Intermediate Position, Handwinding
KIF A type of sprung jewel setting which allows the jewel to
move and protect the pivots when the watch is affected by some sort of shock.
See also Shockproofing, Parashock, Cap Jewel, Pivot, Chaton, Incabloc
Lepine A mechanical watch calibre in which all of the pivots on the
top plate have separate bridges to facilitate easy servicing. This includes:
barrel bridge, centrewheel bridge, 3rd wheel bridge or cock, 4th wheel bridge or
cock, escape wheel cock, balance cock. See also Cock, Bridge, Pivot, Wheel,
Train
Lever A mechanical part which translate rotational motion into
sliding/translational motion by means of a rigid part rotating about a pivot.
Used in virtually every watch, be it in the keyless works or some form of
complication. The pallet fork Is
also known as the lever. See also
Finishing, Graining, Anglage, Pivot, Chronograph, Complication, Keyless Works,
Sonnerie, Minute Repeater
Ligne An archaic measurement of the diameter of the movement. One
Ligne equals approximately 2.25583 millimetres.
Lubrication Reduction of friction by application of appropriate
oil or grease. See Bearing, Oiling, Oil Lugs The point at which the
strap, band or bracelet attaches to the case of a watch. See SEL, End Link,
Bracelet, Integrated Lugs, Floating Lugs, Band, Strap
Lumibrite Seiko proprietary luminous compound. Similar to
Superluminova. See also Luminosity, Luminova, Superluminova
Luminosity A feature which enables the watch to be read at
night. This usually takes the form of some sort of coating applied to the hands
and dial, but might be a small sealed glass capsule (Traser). Early luminous
compounds were phosphorous based compounds triggered by radioactive compounds,
mainly Radium and Tritium; nowadays, entirely non-radioactive materials are
used, mainly rare-earth metal based. Nonradioactive luminous compounds require
exposure to UV light before they will glow, as it is necessary to excite the
compound to a higher energy atomic state. Once in that state, the atoms will
decay and in doing so emit energy in the form of a photon, or visible light.
Prior to luminous compounds, the only way to tell the time in the dark was by
means of audible complications (repeaters) or Montres a Tact. See also Lumbrite,
Luminova, Superluminova, Tritium, Radium, Repeater
Luminova A generic non-radioactive luminous compound. Lately
superseded by Superluminova. See
also Luminosity
Magnifier An optical lens attached to the crystal of a watch to
increase the apparent size of an indication on the dial, usually the date. See
also Cyclops, Crystal
Mainspring The spring contained within the barrel which provides
torque to the timekeeping train. The term mainspring is also applied to any
additional barrel which is used to provide power to other complications such as
a foudroyante chronograph or sonnerie. See Barrel, Arbor, Complication,
Foudroyante
Maltese cross A specially profiled gear which is used mainly for
two things: 1) moving an indication by a fixed amount intermittently, for
example calendar indications using a guichet; 2) limiting barrel rotations to
ensure torque consistency and thus rate stability. See also Barrel, Mainspring,
Torque, Calendar, Guichet, Big Date, Perpetual Calendar, Annual Calendar
Manufacture There is much hot debate over exactly what
constitutes a manufacture, but I believe an adequate definition is as follows. A
watchmaking house can be called a manufacture if it produces, finishes and
assembles at least one calibre in-house.
Marker A printed or applied mark on the dial of a watch used to
indicate a particular increment, i.e. hours or minutes. These may be luminous.
See also Dial, Luminosity, Enamel
Mechanical Any movement which obtains running power from a
mainspring only is defined as mechanical, be it handwound or automatic. See also
Quartz, Handwound, Automatic
Micrometric regulator
A type of regulator which allows fine manipulation of the index for precise
regulation. Used in movements which are not free sprung, i.e. require
interference with the length of the hairspring to alter rate. See also
Hairspring, Rate, Adjustment, Timing, Regulator
Microrotor An automatic winding rotor which is both
decentralized and has a smaller diameter than the movement in which it is
housed. Usually used when an ultra thin movement is required as integrating the
rotor reduces the overall thickness. May be made from a high density material
such as platinum or gold to compensate winding efficiency for the lack of size.
See also Gold, Platinum, Reduction Gear, Automatic winding
Mineral crystal
A type of hardened glass with hardness 7 on the Mohs scale. (Sapphire is 9) It
is prone to scratching, chipping and may crack or shatter if dropped. It is also
not polishable like acrylic crystals if scratched. See
Minute Repeater
An audible complication which chimes the hours, quarters and minutes on demand
on two gongs. The hours are struck on a low gong, quarters alternating, and the
minutes on a high gong. It is also possible to have a carillon minute repeater,
in which more than two gongs are used. in this case, the hours are still struck
on the low gong, minutes on the high gong, but the quarters will be some
combination of all three. See also Repeater, Hour Repeater, Quarter Repeater,
Five Minute Repeater, Carillon, Gong, Chime, Hammer
Modular Construction
A movement where the complications or additional functions are not integrated in
the base (timekeeping only) movement. See also Complication, Complication plate,
Plate
Moisture indicator -
Most of the moisture indicators are copper sulphate based - anhydrous copper
sulphate, which is without water of crystallization (i.e. completely dry and can
absorb water) is pure white. It can be mixed with paint and primers and still
retain its properties. When mixed with water, anhydrous copper sulphate takes on
water of crystallization (five H20's per CuSO4 molecule) which makes it hydrated
copper sulphate. This is blue, and crystalline rather than powdery like they dry
stuff.
Moonphase An indication which displays the current phase of the
moon. Typical moonphase gearings are driven once per day and give the moon a
period of 29.5 days; synodic moonphases are driven continuously from the hour
wheel and have a greater accuracy, some to as little as 1 day in 1085 years
(which is very close to the true period of the moons orbit, 29.5308 days).
See also Synodic Moonphase, Calendar, Pusher
Monopusher A type of chronograph that is operated with a single
pusher, rather than the normal two. There are two types: 1) First push starts,
second push stops, third push resets; 2) First push performs a flyback start,
second push stops, and third push performs a flyback start again. See also
Chronograph, Rattrapante, Flyback, Foudroyante, Reset Lever, Heartpiece
Montre de pochet
A pocket watch
Mother of pearl
Material made from the inner lining of the abalone or oyster shell, prized for
its lustre and depth of colour; occasionally used as a material for dials. See
also Dial, Guilloche, Engraving, Finishing
Movement The assembly of parts which powers the timekeeping functions
and any other complications in a watch. May be mechanical or quartz. See also
Mechanical, Quartz, Automatic, Handwinding
Multiple axis tourbillon
A tourbillon which rotates about any extra axes on top of the one running
through the balance staff. See also Tourbillon, Balance, Balance Staff, Dual
axis tourbillon, Torkel tourbillon
Nivarox An extremely resilient and thermally stable alloy used for
making hairsprings. Trade name for a
form of the alloy Elinvar. See also Hairspring
O-ring An annular sealing ring, with circular cross section,
usually made of rubber or silicone, and used to provide a case seal against dust
and moisture. See also Gasket, Oil, Silicone
Observatory Traditionally a place at which timing observations of
a watch were performed. Also carried out timing competitions (Observatory
Trials) and issued chronometer certificates. See also COSC, Timing, Regulation,
Adjustment, Observatory Grade, Observatory Trial
Observatory grade
A watch which has successfully passed whatever timing criteria have been set by
the observatory. The most common observatory grade in modern times is known as
Chronometer certified, which is issued by the COSC. See Observatory, Timing,
Rate, Adjustment, Regulation, COSC
Observatory trial
A competition where manufactures submit their watches for timing tests, and
prizes are awarded to the best watch in various categories, such as overall mean
daily rate, rate stability, best positional adjustment, etc. See also
Observatory, Timing, Rate, Adjustment, Regulation
Oil Any fluid which is used as a lubricant in order to reduce
friction between moving parts, such as pivots and bearings, or the working faces
of levers. See also Gear, Pinion, Bearing, Pivot, Lever
Oiling The process by which oil is applied to a movement. See also
Oil
Overcoil The name given to the treatment of the final coil in a
hairspring. Various types are used, including Breguet and Philips. See also
hairspring, Breguet Overcoil, Philips Overcoil, Dog Leg, Terminal curve
Pallet See Pallet Fork
Pallet fork Used somewhat interchangeably with the term Pallet
Lever in describing the part which holds the pallet jewels for the escape wheel.
The end holding the jewels interacts with the escape wheel, and the other end
provides the impulse to the balance via the impulse jewel. On tourbillon
escapements the pallet fork has to be somewhat modified in order to fit within
the confines of the tourbillon cage. The pallet fork is held in place using the
pallet fork bridge, which is typically attached to the baseplate at one end
only. See also Escapement, Balance, Pallet, Pallet fork bridge, Pallet Stone,
Escape Wheel
Pallet stone The name given to the rhomboid jewels which perform
the locking and unlocking functions in the escapement. These are attached to the
arms of the pallet fork and interact with the escape wheel teeth faces. May be
made of ruby, or in some escapements, diamond, and even steel and plastic. See
also Pallet Fork, Pallet stone, Escapement, Escape wheel
Parashock - A type of sprung jewel setting which allows the jewel
to move rather and protect the piviots when the watch is affected by some sort
of shock. See also Shockproofing, Parashock, Cap Jewel, Pivot, Chaton, Incabloc,
KIF
Perlage A type of finishing where a small rotating disc is placed on
the surface to be finished, creating a circular brushing. This is then repeated,
with each brushing partially overlapping the previous one, thus giving a fish
scale type effect. The combined finish is known as perlage. Also
known as spotting. See also
Finishing, Brushing
Perpetual calendar
A calendar mechanism which, by means of a program wheel, self-compensates for
months with less than 31 days, and also in addition leap year cycles. Typically
displays date, day, month, moonphase, leap year cycle, and occasionally, year
indications. Perpetual calendars are sometimes combined with other calendar
based complications such as secular calendars, astronomic indications, sunrise
and sunset indicators, equation of time indicators, etc. See also Annual
Calendar, Secular Calendar, Astronomic Indications,
Perspex crystal
A type of crystal made from a plastic based material. Whilst being relatively
soft, it is also very shock resistant and effectively shatterproof. Prone to
scratching but easy to polish out scratches. See also
Physical vapour deposition (PVD)
A process by which a coating is bonded at the molecular level to the desired
surface. It is much more durable and hard than regular electroplating. Applying
a PVD coating requires high temperatures and pressures and specialist equipment
to perform. A common question is what determines the nature of the finish
the answer is that it reflects the underlying treatment of the surface beneath.
If polished, then the PVD will also be polished, if beadblasted, then the PVD
will reflect this also. See also Plating
Pin buckle A type of strap fastening which uses a pin passed
through a hole in one end of the strap and several retaining loops in order to
keep the strap fastened. May be replaced by a deployant clasp in some cases to
prolong the life of the strap. See also Strap, Band, Deployant Clasp
Pinion A small diameter gear with no spokes attached to a shaft,
usually used in the train of a watch. Usually made of steel. The tooth profile
of a pinion is hypocycloid in order to maximise efficiency of force transfer
between gears. See also Gear, Pivot, Steel, Torque
Pivot The end of a shaft which resides in a bearing. Usually
polished in order to reduce rotational friction. See also Gear, Pivot, Pinion,
Bearing, Jewel
Planetarium A type of astronomical indication in which the orbits
of the planets are displayed, or some sort of earth-moon-sun system is
represented. Typically these displays are quite inaccurate due to the extremely
long periods of time involved (237 years for one orbit of Pluto) and the limits
in possible gearing ratios. Usually combined with a perpetual calendar in order
to set the indications accurately. See also Perpetual Calendar, Astronomical
Indication
Planetary gearing
A type of gearbox, usually reduction, which uses a cluster of identical sized
gears which mesh with the inside rim of another gear. The identical gears are
equally spaced and at their centre is another gear, which is connected to the
output shaft. The input shaft is via the common plate holding the cluster of
gears. It is a very efficient way of creating reduction gearing due to the large
ratios that can be achieved within a small space. See also Gear
Plate Any piece of material which is fixed in position, and may or
may not have bearings fixed into its surface. E.g. baseplate, top plate. It may
also refer to a modular complication which is constructed separately of the base
movement and then attached via a driving gear and screws, e.g. perpetual
calendar plate. See also Complication plate, Modular construction, Baseplate,
Top Plate
Plating A type of surface finish applied using electrostatic
potentials between the item being plated and the desired plating material. The
plating is held on by electrostatic forces only and thus is not very resistant
to scratches, and is easy to remove. A metal will only plate to another metal if
it is lower in the reactivity series than the base metal. The reactivity series,
from most to least reactive, goes in the approximate order potassium, sodium,
calcium, magnesium, aluminium, zinc, iron/steel, tin, titanium, silver, gold,
platinum (family of metals). Thus it is possible to aluminium plate magnesium,
and platinum plate gold or silver, but not to gold plate platinum. See also
Physical Vapour Deposition
Platinum A white-grey very dense and unreactive metal, extremely
resistant to corrosion and very hard. Typically used in watch cases or
oscillating weights, with purity 950 parts per thousand. The remainder metal in
the alloy is always another metal from the platinum family palladium,
rhodium, osmium, or iridium. It is a difficult metal to machine and work with
due to its density and very high melting point; and also difficult to polish
once scratched.
Poinηon
de Genθve
The formal name for the hallmark of the Geneva Seal.
Polishing A finishing process by which the surface of a part is
smoothed out and flattened to a reflective state. This is accomplished by using
initially rough grades of polishing compound, and then increasingly fine grades
until no graining is visible. Polishing of functional surfaces is necessary in
order to reduce friction, and this includes gear teeth, pinions, pivots, lever
faces, etc. See Lever, Gear, Pinion, Pivot, Finishing, Graining, Brushing
Poise The balance of the balance wheel, so to speak. To
poise a balance is to remove material or shift weights on the balance in
order to make sure that its centre of gravity runs through its axis of rotation
in order that it runs smoothly. If a balance is out of poise, the resulting
effect will be excessive wear on the balance staff pivots, and irregular timing
due to differences in the length of its swing. Old balances were poised by the
use of timing screws and washers; moving the screws or adding/removing washers
changed the effective mass distribution and thus the poise of the balance.
Modern balances are mostly laser poised by cuts in the rim of the balance (made
by small drills or cutters) or alternatively by altering the position of movable
weights (if the balance is free sprung). See Balance, Balance Staff, Free Sprung
Balance, Timing Screw, Timing washer
Position A particular orientation of the crown and dial, noted for
regulation, adjustment and timing purposes. Watches adjusted to five positions
will take into account the positions crown up, crown down, crown left, dial up,
and dial down. A sixth position, crown right, is sometimes used, and
occasionally when eight adjustments are made, then two intermediate 45 degree
positions are used. See also Regulation, Timing, Rate
Power reserve The length of time a movement will operate for
without interference from the wearer once the mainspring has been fully wound. A
power reserve somewhere in the region of 40-45 hours is common, and of late,
anywhere as much as ten days (Patek Philippe Ref 5100 and 5101P Tourbillon) for
special designs. Fast beat movements will use more power as the balance has to
be accelerated to change the direction of its swing more often. Note that the
power reserve of the watch might not necessarily represent the time that it can
run with acceptable timing; often in the last day or so of the power reserve the
mainspring torque will be insufficient to ensure good amplitude, hence the
desire for longer power reserves. This problem can be partially remedied by the
use of constant force devices (remontoires) and Maltese crosses to limit the
number of barrel revolutions. Sometimes confused with the term power reserve
indicator. See also Power Reserve Indicator, Torque, Barrel, Remontoir, Maltese
Cross, Mainspring, Differential Gear, Tourbillon, Frequency, Fast Beat, Slow
Beat
Power reserve indicator
A complication which displays the state of wind of the main barrel. Usually
accomplished by a mechanical counter for the number of revolutions that the
barrel has undergone in one direction or another. A differential is used to
account for both winding and unwinding of the barrel. Alternatively, a conical
screw may be used which rises and falls as the barrel is wound and unwound. An
arm then reads off the slope of the cone and then displays the power reserve by
means of a pointer on a dial. See also Power Reserve, Dymograph, Torque,
Mainspring, Barrel
Program wheel Any sort of wheel with irregular teeth; this can be
used to coordinate any functions from chronographs (in the form of column
wheels) to sonneries and perpetual calendars. In a perpetual calendar, the
program wheel has a series of notches of varying depth which represent the
months where the date has to be advanced by a day or three, depending on the
year. It also accounts for leap years. A lever reads off the adjustment required
at the end of the month by means of rising and falling out of the notches. The
perpetual calendar has a four year program wheel; an annual calendar will have a
one-year cycle which does not account for leap years. See also Perpetual
Calendar, Annual Calendar, Column Wheel, Chronograph
Pulsometer A scale located concentric to the minutes scale on a
doctors chronograph (usually either on the dial or the bezel) which enables
the number of respirations per minute to be determined using the second hand. By
timing the duration required to complete an event, a rate in units/hour or
units/minute can be determined. Usually operated in conjunction with a
chronograph. See also Bezel, Chronograph
Push-piece A recessed button not normally used in the running of
the watch, but used to correct indications or functions, such as those of a
calendar or moonphase. A special tool or sharp implement is usually required to
push these buttons to prevent accidental mis-settings. See also Pusher,
Calendar, Perpetual Calendar, Moonphase
Pusher The name given to the buttons used to activate watch
functions, almost always referring specifically to chronograph functions.
Pushers may be bucket type (the stem is exposed), shaped (non-circular, e.g.
square or elliptical), screw down (pusher has a protective collar that can be
bolted to guarantee water resistance, much in the same way as a screw down
crown) or shouldered/guarded (pusher has a protective flange to prevent
accidental damage). Some pusher designs are self-lubricating (e.g. Sinn 756,
Omega Seamaster Chronographs), and may also be operable underwater (e.g. Omega
Seamaster Chronographs). See also Chronograph, Push-piece
PVD See Physical Vapour Deposition
Quarter repeater
An audible complication which chimes the hours and quarters on demand on two
gongs, i.e. on the activation of the repeater system by means of a push button
or slide. The hours are struck on the low gong, and the quarters on a high gong,
or alternately the quarters may be struck on an alternation of the two. See also
Repeater, Minute Repeater, Hour Repeater, Gong, Chime, Hammer
Quartz A type of electric movement in which a quartz crystal is
stimulated by electricity and oscillates 32,768 times per second. A
microcomputer counts these oscillations, and then uses a stepper motor to
advance the second hand by six degrees each second. In analog quartz, the second
hand is connected to the hour and minute hands by means of a conventional train.
In digital quartz, the computer is connected to a liquid crystal display which
shows the time graphically. More accurate and much cheaper than mechanical
movements, but unless temperature compensated is liable to some rate variations
with temperature. See also Movement, Frequency, Train
Rack Any lever with gear teeth attached; may be a segment of a
circle (e.g. gears that dont make a full revolution, like power reserve
indications), or otherwise (like repeaters). Typically taken to mean the toothed
lever in a repeater which interacts with the hammers, causing them to strike the
time. See also Minute Repeater, Minute Repeater, Quarter Repeater, Five Minute
Repeater, Hour Repeater, Gear, Lever, Hammer, Power Reserve Indicator
Radium A naturally occurring radioactive element and the first
luminous compound used on watch dials. Required mixing with a phosphor in order
to fluoresce in the visible spectrum. See also Luminosity
Rapid change date
A system of levers and detent springs which allows the date to change very
quickly at
Rapid advance The name