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A Brief Glossary of Technical Terms (continued)


PILLAR


PINCHBECK, Christopher

A brass post separating the two plates of a full-, half- or three-quarter-plate movement.   Until about 1790 pillars were of
various ornamental forms, usually rectangular or polygonal in cross-section;  afterwards they were cylindrical.

(1670-1732)   English clock- and watchmaker, inventor of the gold-like alloy (a form of brass) which bears his name.

PINION

A small wheel mounted on the same arbor as a larger one and generally used to transmit the drive between that wheel
and another.   Pinions are usually of steel and have six or eight ‘leaves’, as their teeth are called.


PIN SETTING

Essentially the same as lever setting, with the difference that a push-pin is used to disengage the hands from the train
so that they can be set without stopping the watch.

PIROUETTE

A device invented by Huygens for increasing the arc (and therefore the momentum) of the balance-wheel in a verge
escapement.   The balance-staff carries a pinion which engages with a vertical wheel of contrate form;  the pallets are on
the arbor of this rather than on the balance-staff itself.

PIVOT

The narrow tip of an arbor, rotating in a hole pierced in one of the plates (usually, since the late 1800s, with a jewel by
way of bearing).  The steel used for arbors is quite brittle and pivots often break, especially at the outer end of the
balance-staff.

PIVOTED DETENT

A type of escapement invented by Pierre le Roy, in which pallets mounted on the rim of the balance-wheel itself interact
with the four long spokes of a rotating component (the detent) to achieve locking.

PLATE

A panel of brass or (in more recent times) nickel, pierced with a number of holes to receive the pivots of a watch's
moving parts.   Until the late 1700s there were two plates, separated by pillars, and most of the movement was
sandwiched between them;  then came the Lépine calibre which led directly to the modern layout with only one plate,
behind the dial.  

POKER HAND

The minute-hand of a typical 18th-century English watch, slim and tapered, with a touch of ornament near each end;
used in conjunction with a beetle hour hand.

PORCELAIN

An incorrect but common term applied to dials which are actually enamel.

POSITION ERROR

Variation in a watch's rate when it is held or suspended in different positions.   This is most often encountered in
unrestored movements which (for example) run badly or not at all when placed upright or dial downwards, usually
because the the balance-staff pivots are worn or the table of the cock is out of true;  but it can occur on a smaller scale
even in a sound and well-maintained movement, where it is a result of imperfectly balanced components or imprecise
tolerances between interacting parts.   Quality watches are often tested by their makers in different positions, and in
20th-century Swiss and American examples the fact may well be recorded on the movement with some such notation as
‘Adjusted 5 positions’.

POTENCE

A small bracket, screwed to one of the plates, to support one end of an arbor.   Bridge, cock and potence are overlapping
terms;  essentially they all mean the same thing, but cock is generally used only of the bracket over the balance-wheel,
while bridge is preferred where the component is attached to the top plate and potence where it is mounted on the bottom
plate or between the plates.  

PRIVATE LABEL

An American watch made by one of the large factories for a retailer, whose name appears on the movement instead of
that of the maker.   Private-label watches have a following of their own amongst collectors.

PUMP-WIND

An early form of keyless winding, using a plunger to operate a lever mounted on the bottom plate, acting on a ratchet,
to turn the fusee cone or going barrel.   Unlike stem-winding, this lent itself readily to use in conjunction with a
fusee, and so it had a certain currency in 19th-century Britain, but it never became popular.

PURITAN WATCH

A mid-seventeenth-century English watch of very plain design, precursor of the classic pocket-watch as we still know it
with white enamel dial and minimally decorated silver or gold case.   So called in allusion to the austere religious
fundamentalists popularly so called, who were socially and politically influential at the time.

QUARE, Daniel

(1649-1724)   English clock- and watchmaker, inventor of the repeater.   Together with Tompion, Quare deserves a large
share of the credit for establishing England as the world's leader in horological matters throughout the 18th century.

QUARTER REPEATER

A repeater which indicates the last completed quarter-hour by striking the hour itself on one gong followed by one, two or
three blows, each representing fifteen minutes, on a second.

QUATRE

(French) Four.   Old Swiss watches are often stamped quatre rubis (four jewels);  this is the absolute minimum number in
a respectable watch, indicating that only the balance-staff is jewelled.

RACK-LEVER

An escapement patented by Peter Litherland of Liverpool in 1791, using a principle outlined by Jean Hautefeuille in the
1720s.   It resembles a side lever, but instead of a fork the inner end of the lever carries a toothed quadrant which
engages with a pinion on the balance-staff.   It had a certain vogue in England between about 1810 and 1825 and is
also occasionally found in Germany.

RAILROAD WATCH

A watch designed for use by railway officers — not necessarily actually applied as such, but designed and adjusted to
meet the standards that this application would require.   Watches marked ‘Chemin de Fer’ or ‘Railway Time Keeper’ begin
to appear in Europe in about 1850, but the true railroad watch is an American phenomenon.   It reached its height in the
early 1900s, when the principal U.S. railroad companies produced specifications for watchmakers, laying down not only
the level of accuracy but also such matters as size, number of jewels (minimum 19 from 1920 onward) and even materials
(plastic crystals were disliked because they easily acquired scratches and because they harboured condensation
which imperilled the finish of the moving parts).   Because of the manufacturers' habit of offering different levels of finishing
and adjustment, a particular model may well exist in both railroad and non-railroad grades, and the dividing line between
them is an object of endless discussion and dispute.   The Hamilton company specialised in railroad watches
and its 992B model, still in production in the 1960s, is sometimes accounted the summit of the genre.

RAMSAY. David

(?-1654)   Scottish clock- and watchmaker, trained in France and appointed clockmaker to King James I in 1613.   He
was the first Master of the Clockmakers' Company on its incorporation in 1631.   He was a prolific inventor in several
branches of trade and engineering, from mining to textile-dyeing.   He plays a significant part in Sir Walter Scott's novel
The Fortunes of Nigel, where his daughter marries the hero.

RATE

(1)   The deviation of a timekeeper from strict accuracy, expressed as an average.   Thus an early chronometer might
be said to have a [gaining or losing] rate of (say) five seconds a week, and this would be taken as read in judging its
performance thereafter;  provided it never deviated materially from this rate it could be regarded as virtually perfect
for its purpose, since an error so constant could easily be compensated for by calculation.

(2)   By extension, the word rate came to be applied, without qualification, to a watch's standard of performance;  “it has
a good rate” is merely professional jargon for “it keeps good time”.

RECOIL

In some escapements, the slight reverse motion of the escape-wheel when it meets the pallet responsible for locking.
Recoil is in theory undesirable, since it hampers the free movement of the controller;  but sometimes it is allowed for
and indeed turned to advantage in making the locking process secure (see draw).   This is true, for example, of the lever
escapement, where the interposition of the lever prevents recoil from affecting the balance.

REGULATOR

A device for altering the effective length of a balance-spring by sliding the curb-pins, which lightly restrain it close to its
outer end, back and forth along its length.   The earliest balance-spring watches used the Barrow regulator, which
incorporated a worm-drive.   This was followed in about 1680 by the Tompion regulator and then, a century or so later, by
the Bosley pattern which dispensed with the need for a key and has remained in use every since.

REMONTOIR

This word, stamped on the cuvette of a Swiss watch, often constitutes a bitter disappointment to collectors who believe
they have found a watch fitted with the sophisticated item described in the next entry.  In fact, it is merely French for
stem-winding.

REMONTOIRE

An arrangement, invented by John Harrison and found only in chronometers and first-class watches, for preventing the
declining power of the mainspring as it unwinds from creating a loss of pace at the balance.   (The fusee cannot do this
precisely enough.)   The remontoire consists of a small slave drive-spring, wound automatically at very short intervals
(perhaps only a few seconds) by the power of the mainspring;  it is this slave spring which powers the escapement, the
mainspring having no influence on this part of the train.   Thus the watch ‘runs down’ and is automatically re-wound
hundreds of times a day – often enough for the momentum of the balance to carry it over the tiny loss of power, which
in any event is averaged out over the watch's daily rate.

REPEATER

A clock or watch that chimes the last completed hour (and often the quarter-hours as well) when a plunger or slider is
operated.   The necessary mechanism is usually housed between the dial and the front plate, so that it adds very little to
the bulk of the watch;  this compactness is possible because the repeater never has to strike more than 15 times (12
o'clock plus three quarters) at one winding (compare 156 times for a 24-hour clock-watch), so that only a small
drive-spring is required;  the plunger winds this by pulling a chain.   Daniel Quare invented the repeater in about 1680.

REVERSING PINION

A device which enables the hands of a key-set or stem-set watch to be moved without disturbing its running.   (Moving
the hands on a watch without this provision can produce some very odd consequences, especially if they are moved
anti-clockwise;  a lever watch may actually run backwards in this situation.)   It is found from about 1880 onwards and
is also called safety pinion, this being apparently the preferred term in the U.S.A.

ROLLER

A polished steel disc mounted on the balance-staff of a lever watch.   The side that faces towards the lever (when the
watch is at rest) has a sector cut out of it, and just inboard of this stands the impulse-pin (a peg made of ruby), which
engages in the fork of the lever.

ROSKOPF, G. F.

(1813-1889)   German watchmaker who settled in Chaux-de-Fonds, Switzerland, and set up a factory to produce a
watch of consistently sound quality at a lower price than had previously been possible.   He did this by applying
American production-line methods and by simplifying the train, which had only three wheels.   The escapement was of
the Perrot type.   The Roskopf ‘People's Watch’ appeared in 1868.

RUBI

(French) Ruby.   In the inscriptions on the cuvettes of French and Swiss watches, the jewels tend to be described as
rubis rather than by the more general word joyeaux (‘jewels’).

RUBY

The mineral most commonly used for jewels.   Sapphire, amethyst and aquamarine have also been applied.


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