Derived from Latin ad justus, meaning just right Adjusted to
compensate for temperature, positions and isochronism.
A watch that will give an audible sound at a pre-set time.
ALL OR NOTHING PIECE
A repeating Watch mechanism which ensures that ALL the hour & minutes
are struck or sounded or nothing is heard.
A term used to denote a watch dial with hands rather than digital
Heating and cooling a metal slowly to relieve internal stress.
Not affected by magnetic field.
Of antiques or dealing in, also the study of old and out-of-date
The mechanical axle of a moving part; on the balance it is called the
staff, on the lever it is called the arbor.
Analyzing a metal for its gold or silver content.
Automatic working figures moving in conjunction with the movement
mechanism. Striking Jacquemarts or jacks which are figures (may be
humans provided with hammers) striking bells to supply the sound for
the hour & quarter hours. The hammers take the place of the bells
clapper, Automata plural of automaton.
For middle temperature errors found on marine chronometers.
Any extra dial for information.
American Watchmakers-Clockmakers Institute, 701 Enterprise Drive
Harrison, OH 45030. Tel # (513) 367-9800
(BOX CASE) BREGUET KEY
A ratcheting watch key permitting winding in only one direction.
A French term for oblong shape. A watch having it's length at least 3
times it's width. A long narrow diamond.
The bridge that holds the upper jewels and the balance and secured at
one end only.
Also called the hairspring; the spring governing the balance.
The shaft of the balance wheel.
A device shaped like a wheel that does for a watch what a pendulum
does for a clock.
The two pins that limit the angular motion of the pallet.
A type of movement employing about six bridges to hold the train. In
use by 1840.
Drum-shaped container that houses the mainspring.
Refers to the tick or sound of a watch; about 1/5 of a second. The
sound is produced by the escape wheel striking the pallets.
Hour hand resembling a stag beetle; usually associated with the
poker-type minute hand in 17th and 18th century watches.
Four parts copper and one part tin used for metal laps to get a high
polish on steel.
The rim that covers the dial (face) & retains the crystal. Above snap
A balance composed of brass and steel designed to compensate for
temperature changes in the hairspring.
A Braille watch; also known as a tact watch.
By heating polished steel to 540 degrees the color will change to
Convex on one side.
The ring that is looped at the pendant to which a chain or fob is
A marine or other type chronometer in gimbals so the movement remains
level at sea.
BOX JOINTED CASE
A heavy hinged decorative case with a simulated joint at the top under
A type of hairspring that improves time keeping also called over coil
A metal bar which bear the pivot of wheels and is supported at both
ends. (See cock.)
A Rolex wristwatch that was waterproof (Oyster) and auto wind
(Perpetual) Ca. 1930 to 1950's.
Buffer spring is a stop spring for oscillating weight.
Used on old type watches; the center of the crystal was polished which
achieved a bull's eye effect.
An unfaceted cut stone of domed form or style. (On some crowns)
Size of a watch movement also to describe the model, style or shape of
a watch movement.
Also called the end stone, the flat jewel on which the staff rests.
A screw with part of the head cut away.
The second wheel; the arbor for the minute hand; this wheel makes one
revolution per hour.
Looks like a miniature bicycle chain connecting the barrel and fusee.
Sloping or beveled. Removing a sharp edge or edges of holes.
An area hollowed out and filled with enamel and then baked on.
The hour, minute & seconds numbers on a dial. The chapter ring is the
zone or circle that confines the numbers.
A movement that can be started and stopped to measure short time
intervals and return to zero. A stopwatch does not keep the time of
A detent escapement used in marine chronometers.
A pawl that ratchets and permits the winding wheel to move in one
direction; a clicking sound can be heard as the watch is wound.
A watch that strikes the hour but not on demand.
Enamel set between strips of metal and baked onto the dial.
Some escape wheels have a special design which increases the impulse
plane; located at the tip of the tooth of the escape wheel
16,000 beats per hour.
The metal bar that carries the bearing for the balance's upper pivot
and is supported at one end.
A balance wheel designed to correct for temperature.
A watch with complicated works; other than just telling time, it may
have a perpetual calendar, moon phases, up and down dial, repeater,
musical chimes or alarm.
A wheel with its teeth at a right angle to plane of the wheel.
Movement made by Elgin & other companies; a means of converting from a
hunting case to a open-face watch or vice versa.
A minute crack in the glaze of enamel watch dials.
A winding button.
The escape wheel of a verge escapement; looks like a crown. Also the
lower illustration shows a crown wheel used in a stem winding pocket
The two pins that change the rate of a watch; the two pins, in effect,
change the length of the hairspring.
The inter dust cover of a pocket watch.
A type of escapement used on some watches.
The art of producing a design, pattern, or wavy appearance on a metal.
American idiom or terminology used in all American factory ads. The
European terminology was Fausse Cotes or Geneva stripes.
A hunting case with the center designed to allow the position of the
hands to be seen without opening the case.
A detached escapement. The balance is impulsed in one direction; used
on watches to provide greater accuracy. Detent a locking device.
The face of a watch. Some are made of enamel.
DISCHARGE PALLET JEWEL
The right or 2nd jewel on lever. The 2nd of two pallet jewels with
which a tooth of the escape wheel comes into engagement. Also called
the Exit pallet.
A watch with one impulse roller table and a safety roller, thus two
The angular position of the pallet jewels in the pallet frame which
causes those jewels to be drawn deeper into the escape wheel under
pressure of the escape wheel's tooth on the locking surface.
The space between a tooth of the escape wheel and the pallet from
which it has just escaped.
A repeating watch with hammers that strikes a block instead of bells
An escape wheel with two sets of teeth, one for locking and, one for
A movement not completely finished or in the rough; not detailed; a
raw movement; a movement made up of two plates, train, barrel & did
not include a dial, case, or escapement.
Not exactly circular, Non-concentric. A cam with a lobe or egg shape.
Newer type watch using quartz and electronics to produce a high degree
A hairspring composed of a special alloy of nickel, steel, chromium,
manganese and tungsten that does not vary at different temperatures.
Elinvar was derived from the words elasticity invariable.
The up and down play of an arbor between the plates and bridge or
between the jewels.
The jewel or cap at the end of the staff.
Engraving a watch case with a repetitive design by a machine.
The time calculated for the Earth to orbit around the sun.
The last wheel in a going train; works with the fork or lever and
escapes one pulse at a time.
The device in a watch by which the motion of the train is checked and
the energy of the mainspring communicated to the balance. The
escapement includes the escape wheel, lever, and balance complete with
FARMER' S WATCH
A large pocket watch with a verge escapement and a farm scene on the
A Latin word meaning "made by".
A watch that denotes the time every five minutes, and on the hour and
half hour, by operating a push piece.
Enameling over hand engraving.
The hand returns back to zero on a timer.
A decorative short strap or chain.
A straight-armed balance with weights on each end used for regulation;
found on the earliest clocks and watches.
The part of the pallet lever that engages with the roller jewel.
A balance spring free from the influence of a regulator.
A plate (or disc) that covers the works and supports the wheels
pivots. There is a top plate, a bottom plate, half, and 3/4 plate. The
top plate has the balance resting on it.
A spiral grooved, truncated cone used in some watches to equalize the
power of the mainspring.
The barrel houses the mainspring; as the spring uncoils, the barrel
turns, and the teeth on the outside of the barrel turn the train of
gears as opposed to toothless fusee barrel.
GENEVA STOP WORK
A system used to stop the works preventing the barrel from being over
GILT (OR GILD)
To coat or plating with gold leaf or a gold color.
GOLD JEWEL SETTINGS
In high-grade watches the jewels were mounted in gold settings.
Sandwich-type metal; a layer of gold, a layer of base metal in the
middle, another layer of gold-then the layers of metals are soldered
to each other to form a sandwich.
A watch or clock that strikes the hour, 1/4 hours and minutes; if
minute repeater, a Petite Sonnerie strikes hour only.
The main wheel of a fusee type watch.
A decorative pattern of cross or interlaced lines. (Engraving style)
A watch with a balance that can be stopped to allow synchronization
with another timepiece.
The spring that vibrates the balance. Also called balance spring.
A hairspring stud is used to connect the hairspring to the balance
The silver or gold or platinum markings of many countries.
A heart-shaped cam which causes the hand on a chronograph to fly back
A cylindrical spring used in chronometers
The study of time keeping.
A pocket watch case with a covered face that must be opened to see the
The force transmitted by the escape wheel to the pallet by gliding
over the angular or impulse face of the pallet jewel.
(Ruby pin)(roller jewel)-A pin or jewel on the balance roller table
that keeps the balance going.
A patented shock-absorbing device that permits the end stone of the
balance to give when the watch is subjected to an impact or jolt.
used in 1933.
A seconds hand driven independently by a separate train but controlled
by the time train.
Another term for the racquet shaped regulator, which lengthens or
shortens the effective length of the hairspring.
"Isos" means equal; "chronos" means time- occurring at equal intervals
of time. The balance and hairspring adjusted will allow the watch to
run at the same rate regardless whether the watch fully wound or
almost run down.
A bearing made of a ruby or other type jewel; the four types of jewels
include; cap jewel, hole jewel, roller jewel or ruby pin, pallet jewel
An invention of Bonniksen in 1894 which allows the entire escapement
to revolve within the watch once in 52 1/2 minutes (in most karrusels),
this unit is supported at one end only as opposed to the tourbillon
which is supported at both ends and which most often revolves about
once a minute.
Older watch that had to be set with a key.
Introduced by J.A. L'Epine about 1770. Swiss for open face.
The teeth of the pinion gears.
Invented by Thomas Mudge in about 1759
The lever used to set some watches.
Arresting the advance of the escape wheel during the balance's free
The metal extensions of a wrist watch case which the bracelet or band
are attached usually with a spring bar.
A flat spring coiled or wound to supply power to the watch. The
non-magnetic mainspring, introduced 1947.
The first driving wheel, part of the barrel.
The part of the stop works preventing the barrel from being over
An accurate timepiece; may have a detent escapement and set in a box
with gimbals which keep it in a right position.
Also equal hours; average mean solar time; the time shown by watches.
Balance screws used for timing, usually longer than other balance
screws; when turned away from or toward the balance pin, they cause
the balance vibrations to become faster or slower.
A millionth of a second.
A regulator used on railroad grade watches to adjust for gain or loss
in a very precise way.
A watch that strikes or sounds the hours and minutes on demand.
The works of a mechanical watch without the case or dial. (quartz
watches have modules)
(Gold) Different colors of gold-red, green, white, blue, pink, yellow
A watch that plays a tune on demand or on the hour.
N. A. W. C. C.
National Association of Watch and Clock Collectors 514 Poplar St.
Columbia, Pa. 17512. TEL. 1-717-684-8261
One billionth of a second.
Nickname for a German watch that was oval-shaped.
Large older (1675) style watch in the shape of a onion or in the shape
of a bulb.
A small well around a pivot which retains oil.
A lever escapement error; the roller jewel passes to the wrong side of
the lever notch, causing one side of the pallet to rest against the
banking pin and the roller jewel to rest against the other side, thus
locking the escapement and stopping the motion of the balance.
The raised up portion of the balance hairspring, not flat. Also called
An extra case around a watch-two cases, hence, a pair of cases. The
outer case kept out the dust. The inner case could not be dustproof
because it provided the access to the winding and setting keyholes in
the watch case.
One of six platinum metals, used in watches in place of platinum,
because it is harder, lighter and cheaper.
The part of the lever that works with the escape wheel-jeweled pallet
jewels, entry and exit pallets.
An early shock proofing system designed to fit as a spring on the end
stone of balance.
Oxidation of any surface & change due to age. A natural staining or
discoloration due to aging.
A number of jewels or stone set close together. Paved in diamonds.
The neck of the watch; attached to it is the bow (swing ring) and the
The rods that hold the plates apart. In older watches they were fancy.
A metal similar in appearance to gold. Named after the inventor. Alloy
of 4 parts copper & 3 parts zinc.
The larger gear is called a wheel. The small solid gear is a pinion.
The pinion is made of steel in some watches.
A watch has a front and a back plate or top and bottom plate. The
works are in between.
A term meaning in balance to equalize the weight around the balance.
(bull's eye crystal)- The grinding of the center of a crystal to form
a concave or so-called bull's eye crystal.
As adjusted to five positions; a watch may differ in its time keeping
accuracy as it lays in different positions. Due to the lack of poise,
changes in the center of gravity, a watch can be adjusted to six
positions: dial up, dial down, stem up, stem down, stem left, and stem
right. Note: Adj. to 5 positions is also 8 adjustments.
A watch with five beats or more per second or 18,000 per hour.
RACK & PINION LEVER ESCAPEMENT
Developed by Abbe de Huteville in 1722 and by Peter Litherhead in
1791; does not use a roller table, but a pinion.
Also called left or entrance jewel, the first of two pallet jewels
with which a tooth of the escape wheel comes into engagement.
A complicated watch that repeats the time on demand with a sounding
A watch with hammered, raised decoration on the case.
RIGHT ANGLE LEVER ESCAPEMENT
Also called English escapement.
Thin layer of gold soldered to a base metal.
The jewel mounted or seated in the roller table, which receives the
impulse from the pallet fork.
The part of the balance in which the roller jewel is seated.
Oscillating weight for self-wind watches.
A pinion in the center wheel designed to unscrew if the mainspring
breaks; this protects the train from being stripped by the great force
of the mainspring
The smaller of the two rollers in a double roller escapement.
Scratch resistant glass with a hardness of 9. Mineral glass has a
hardness of 5.
The skin of a horse, shark, ray fish & other animal usually dyed GREEN
or a BLUE GREEN. Then used as ornamental covers for older watchcases.
A mismatched case and movement; a term used for a hunting movement
that has been placed in an open face case and winds at 3 o'clock
position. Open face winds at 12 o'clock.
The time of rotation of the Earth as measured from the stars. About 3
minutes 56 seconds shorter than the mean solar day.
A type of case composed of alloys to simulate the appearance of
The safety roller and the roller jewel are one single table.
System used to determine the size of the movement to the case.
A watch made so the viewer can see the works. Plates are pierced and
A antique pendant watch that is hinged at jaw to reveal watch.
A watch with four beats per second or 14,000 per hour.
A cam shaped much like a snail. The snail determines the # of blows to
be struck by a repeater. (A count wheel)
Ornamentation of the surface of metals by means of a circle design;
also called damaskeening.
365 days, 5 hours, 48 minutes, 49.7 seconds.
The cheapest Breguet watch which he made with high quality made in
batches or group lots in advance to lower the cost.(ebauches)
Decoration used on a watch movement and barrel of movements.
The metal keeper that attaches The band to The lugs of a wrist watch &
is spring loaded.
A circular tube housing a coiled type spring.
Curved spring and cam to equalize the uneven force of the mainspring
on 16th century German movements.
Name for the axle of the balance.
A device using a gnomon or style that cast a shadow over a graduated
dial as the sun progresses, indicating solar time.
A hinged spring catch with a loop of metal that may be opened to
insert a watch bow.
The metal plate that usually contains the name and serial number.
A twisting force.
(French for whirlwind) A watch that uses a escapement mounted in a
carriage and pivoted at both ends and revolves 360 degrees at regular
intervals of once a minute. The escape-pinion turns around the fixed
fourth wheel. Design to eliminate position errors.
A series of gears that form the works of a watch. The train is used
for other functions such as chiming. The time train carries the power
to the escapement.
Watches sold with both key and stem-winding on same movement.
TRIPLE CASE WATCH
18th and 19th century verge escapement, fusee watches made for the
Turkish market. A fourth case sometimes added is called Quadruple
UP AND DOWN DIAL OR INDICATOR
A dial that shows how much of the mainspring is spent and how far up
or down the mainspring is.
Early type of escapement with wheel that is shaped like a crown.
Gold plated over silver.
Early escapement introduced in the mid 1700s.
WATCH GLASS PROTECTOR
A snap on metal grill that covers the crystal.
A disc of paper with the name of the watchmaker or repairman printed
on it; used as a form of advertising and found in some pair-cased
A watch that indicates how much of the mainspring is spent. The
illustration shows a modified Geneva stop works. (See up and down
A winding wheel's teeth so named because of their shape.