B

Balance:
( Pic )     The oscillating wheel which controls the speed of an escapement, generally used in a portable timekeeper. The time taken for an oscillation of a balance depends upon its mass, the radius of gyration from its center of rotation, and the magnitude of the restoring force, usually the balance spring.

Balance, chronometer:
( Pic )     The chronometer balance has a split laminated rim made by fusing brass on to a steel ring. This is usually fitted with two large compensation adjusting weights with two timing nuts which are used to alter the rate of the chronometer.

Balance, floating:
( Pic )     A pin-pallet lever variant which appeared in the 1960s, the floating balance was designed to reduce balance-pivot friction. This was achieved by supporting the weights of the balance assembly by a balance spring of double helical form. Half right-handed and half left-handed. This double helical form maintains a constant distance between the pinning points while the spring winds and unwinds.

Balance Spring:
( Pic )     Introduced in the last quarter of the 17th century, this device improved the accuracy of balance-control timekeepers from 15 minutes per day to within two minutes per day. Early balance springs had few turns and some were even made from straight wire until it was discovered that by raising the outer turn of the spring and bending it towards the center to form an over-coil, the center of gravity of the spring retains greater concentricity to the axis of rotation of the balance, thereby improving the clock's accuracy.

Balloon clock:
( Pic )     In the late 18th century a bracket clock appeared with a case that was circular in the upper part, descending to a waisted center portion and then spreading out to a more stable, rectangular base.

Banjo clock:
( Pic )     This term is believed to have been introduced early in the 20th century to describe American wall clocks of similar appearance to that originally developed by Simon Willard at Roxbury, Massachusetts.

Barograph clock:
( Pic )     A clock which continuously records changes in atmospheric pressure. Robert Hooke was the first to use a clock to drive a drum carrying a strip of paper on which a pen drew a continuous record of the air pressure.

Baroque:
That part of a clock which may be set to give audible warning at a predetermined time. The mechanism is usually triggered by a lever which moves into a slot in a cam driven by the hour wheel, allowing a hammer to strike the bell.

Barrel:
( Pic )     The cylindrical brass box containing a mainspring, or designed to accommodate cables, cat gut or some other strong and flexable line to receive power from the weights of a clock.

Barrel arbor:
( Pic )     The mainspring barrel generally rotates on the barrel arbor, and the center of the mainspring is attached to it by a hook. In a going-barrel clock it is squared at one end to take the winding key.

Barrel, going:
( Pic )     A barrel driving the train directly via a toothed ring on its periphery. In fusee clocks, the barrel drives the train through a gut or wire line, or chain.

Barrel, hanging:
( Pic )     The hanging barrel differs from the going barrel in that it is attached to the clock plates, and drives the clock through the barrel arbor, which turns the great wheel through a ratchet and click.

Basket top:
( Pic )     A shaped top to the cases of verge bracket clocks of the late 17th and early 18th centuries. In its simpler form it consisted of a rectangle of mitered ovolo moldings veneered with ebony or ebonised wood, surmounted by a brass, bail-shaped carring handle. In more elaborately decorated clocks this top section was made of fretted ormolu, and it was this open metalwork which suggested the name of basket top.

Battery:
When a number of electrical cells are connected together in a series or parallel arrangement, they are collectively known as a battery. This term is also frequently applied to a single cell.

Battery clock:
( Pic )     Alexander Bain designed the first battery clock shortly before 1838. Today the term is applied to portable electric clocks which depend on a dry cell or battery for its electrical power. The older type of battery clocks employed a large bell cell and would run for long periods: the Eureka clock ran for 1,000 days, the Bulle clock for 800 days; whereas a modern battery clock using a small cell will run for approximately one year.

Beak iron, or beck iron:
( Pic )     A somewhat archaic term for a steel anvil or stake on which hot or cold metal is hammered or bent to shape. For clockmaking, anvils may be quite small and formed for holding in a bench vice, larger ones being screwed or driven into the bench top or a large wooden block, and very large ones having an integral base to stand free.

Beat:
The tick of a clock, or the time taken for a pendulum or balance to swing from its center, or dead point, to one extreme and return to center again. Most clock excapements beat twice per cycle. The beats should be equally disposed about the center or dead point of the pendulum or balance. Single-beat escapements, such as the chronometer and duplex, have one beat on each alternate swing of the balance.

Beam-engine clock:
A clock in the form of an old-fashioned beam engine, with moving parts operated by the clock mechanism to give the appearance of a working model.

Belfry clock:
( Pic )     One of the earliest uses of clocks was in monasteries, to summon the monks to prayer at the proper time. Originally this was done by a water clock giving an aural indication of the hour, at which a monk rang a bell to summon the other brethren. Later, mechanical clocks performed that function. As the name suggest, the clock is in the shape of a tower, and as the hour is due to strike doors open at the base of the tower to reveal the figure of a monk who pulls a cord and apparently causes the hour to sound from a bell at the top of the tower.

Bell:
The sonorous metal dome on which clocks and alarms strike. Antique clocks have bells cast in bell metal, which is a copper-tin alloy containing approximately four parts copper to one part tin. Modern alarm-clock bells are often pressed from sheet steel, and bells have been made of glass.

Bells, nest of:
( Pic )     A number of bells mounted together in chiming or musical clocks.

Bell top:
( Pic )     The bracket clock, true bell-top pattern, with ovolo molding surmounting the cavetto or concave shape, is usually associated with the introduction of mahogany. Old bracket or bell top clocks should never be lifted by their carring handles.

Bell top, inverted:
( Pic )     The inverted-bell top for wooden bracket-clock cases appeared about 1715 and is associated with the general introduction of the arch dial. As its name suggest, the shape is that of a bell reversed and comprises a lower ovolo molding upon which is stepped a cavetto or concave shape. This in turn is surmounted by the brass carring handle.

Bench:
( Pic )     A clockmaker's bench is the basic support for manufacturing or repairing, and carries tools and other equipment. The bench is normally made of timber, but for brazing, soldering or other heat treatments an insulated surface is provided.

Biedermeier:
( Pic )     A style of interior design of circa 1825-1848, which takes its name from a comic character in German popular literature. It typifies homeliness, comfort and simplicity, with a tendency towards lightness of form and the use of light-colored wood. The term is strictly applicable only to Germany and Austria, but contemporary furniture in England shows similar tendencies. In spite of the original Biedermeier characteristic of light colors, many of these cases are finished in shiny black. Some of the pillars are china or alabaster, while white inlay contrasts with the body-color of the cases.

Binnacle clock:
( Pic )     From about 1812 a marine clock had what is now known as 'ship's bell' striking. The minute hand made a revolution every half hour and the hour had every eight hours; a suitable but unconventional dial was provided. It was probably so called because it was supposed it might well be located near the binnacle on a ship.

Birdcage clock:
( Pic )     An ornamental clock constructed in the form of a birdcage containing a mechanical singing bird. The clock movement is in the lower part of the cage and its dial is seen from below when it is hanging from the ceiling. Birdcage clocks were made in Switzerland towards the end of the 18th century, when mechanical singing birds in snuff boxes and similar luxury articles were popular, and when the mechanical musical box began to be made extensively. The term 'birdcage' is also applied to a type of turret clock.

Black Forest clock:
( Pic ) ( Pic )   The Black Forest in south-west Germany embraces the biggest center of clockmaking in the world. The industry began because of the need for local farmers to adopt some indoor occupation during the hard winters. Many took up woodcarving and, according to tradition, a wooden-wheeled clock imported from Bohemia gave them the idea of producing wooden clocks. By the early 18th century certain men had found clock production more to their taste than farming. The earliest clocks had wooden wheels and frames, and were controlled by a wooden foliot balance. The driving weight was a stone, and the clocks only ran about twelve hours. The 18th century saw the addition of striking work, mechanism to operate a cuckoo, 'cowtail' pendulums, and later, anchor excapements with longer pendulums. After brass casting had been introduced into the area about 1780 brass wheels were used instead of wood, although wooden frames and arbors were retained. The making of organ clocks became a separate industry, and production was helped by various mechanical improvements in tools. Production increased until about 1850, when American competition drove the old Black Forest wall clock off the market. The American clock was factory-produced with an all-metal movement and did not have exposed weights and chains. By the end of the 19th century the Black Forest had gone to factory methods. The two world wars had a serious effect on the Black Forest industry: many factories went over to military production, and overseas markets were lost. The area is now chiefly known for alarm and traveling clocks, but the cuckoo clock and the 400-day clock are still firm favorites.

Blinking-eye clocks:
( Pic )     Soon after the iron-front case pendulum shelf clocks had been introduced in the United States, a series of one-day lever movement timepieces cased in cast-iron figures appeared. The earliest of these (about 1856) was 'Sambo', a Negro figure 16in. high holding a banjo, in which a printed-paper dial was enclosed under a glass with brass bezel. The eyes moved up and down, being attached to a swivel actuated by the alternate swings of the balance. By 1858 several other figures had been produced, comprising a line of timepieces known as 'winkers'. These included: 'Topsy', a black woman holding a watch which was the dial (16 1/2in.) 'David Crockett' (16 in.), 'organ grinder'(17 1/2 in.), 'watchdog' (8in.), 'dog' (10 in.), 'owl' (9in.) and 'lion' (10 in.). 'David Crockett' was soon replaced by 'continental' (16 in.), which is now referred to as 'John Bull'. The iron cases were cast in two half-sections held together by screws; frequently the fronts of the castings were painted various bright colors. These were 'gadgets', sold principally in New York and they were discontinued about 1875.

Blowpipe:
( Pic )     A long tapered metal tube through which air is blown by mouth or bellows to increase the heat of a flame and to direct it on to the point where it is needed when brazing or soldering. The blast from the blowpipe through the flame of a spirit or gas burner throws forward a bluish flame which is hottest at its tip, and this is particularly useful where fine controlled heat is required.

Bluing:
The process of changing the color of polished steel by heating to give a protective film of oxidation which also has a pleasing color, brown, purple and blue. The bluing of clock components is normally carried out in a flat thick-bottomed copper bluing pan, the parts to be blued being first polished and cleaned. Care must be taken to heat the parts evenly, keeping them free from cold draughts. Heating is stopped immediately the desired color is obtained. Parts which will not lie flat on the bottom of the pan are blued on a deep bed of brass filings placed in the pan.

Bluing pan:
( Pic )     The bluing of clock components is normally carried out in a flat thick-bottomed copper bluing pan.

Bob:
( Pic )     The weight fitted to the lower end of the pendulum. The commonly found lenticular bob has the advantage of low air resistance. Regulators and electric impulse clocks are often fitted with cylindrical bobs.

Bob, false:
( Pic )     The introduction of the pendulum in clockmaking so revolutionized the timekeeping of clocks that makers found it desirable to show that their clocks were fitted with pendulums. Therefore a small additional bob was attached to the verge staff so as to be visible through an aperture in the dial.

Boiling-out pan:
A small pan used for boiling out parts in methylated spirits, to remove shellac from clock parts after they have been cemented with shellac to a chuck; it is also used for tempering small clock parts in oil.

Bolt and shutter:   See Maintaining power.

Book clock:
( Pic )     In the late 16th and early 17th centuries, when elaborate designs were popular for both clocks and watches, a number of clocks were made in the form of a book, with the movement jointed to the case. The cases were of gilded brass, pierced and chased, and they may be regarded as 'form'watches. Like the watches of the time they contained striking work, alarms, and gave elaborate astronomical information as well as the time.

Bornholm clock:
( Pic )     The Danish island of Bornholm is situated in the Baltic, south of Sweden. Clockmaking is said to have begun there about 1750 when a cargo of English longcase clocks on its way to Russia was wrecked on the island. The inhabitants salvaged them and began making similar clocks of their own. By 1773 Copenhagen clockmakers were complaining about the number of Bornholm clocks on the market. Bornholm clocks may be roughly divided into three groups: painted cases with floral decorations in imitation of Chinese lacquer (1750-1800); Empire style, with decoration of garlands, laurel wreaths, etc. (1800-1830); round topped cases. The industry had died out by about 1890 as a result of Black Forest, French and American competition.

Boulle work:
( Pic )     A form of marquetry of plain or engraved brass with tortoiseshell, taking its name from Andre Charles Boulle. Boulle developed its use greatly, though he has no claim to be its inventor. It was a technique well suited to the late 17th-century taste for rich colors, and the complex panel patterns of the designer Jean Berain that were frequently carried out in this medium.

Brace, hand:
( Pic )     Clockmakers' hand braces are used primarily for broaching large clock pivot holes. They are made of steel, with a cranked handle and square socket for accommodating the squared shank of a broach. see also Broach.

Brace, wheel:
( Pic )     This is primarily a drilling tool and is driven by a hand wheel that is geared directly to the chuck, rotating it, and thus the drill at increased speed. It is a comparatively modern tool and is not entirely satisfactory for accurate work since the tool is hand-held throughout the drilling operation. Twist drills and countersink drills are used with this tool.

Bracket Clock:
The terms 'bracket' and 'mantel' clocks are not synonymous. The bracket clock, was made to stand on a decorative, matching bracket fixed to the wall. Bracket clocks were introduced about 1670, but the mantelshelf as a normal feature of a fireplace first appeared about 50 years later: with it came the mantel clock. The design of bracket clocks changed with contemporary fashion. Between 1670 and 1690, square-dial clocks in ebonised pedimented cases were followed by basket-top clocks. Then came the arch dial, the inverted bell (about 1720) and then the true bell top about the middle of the century. Next came the break-arch case, the balloon clock, the lancet top, the arch top and, the chamfer top.

Bracket Clock, Japanese:
( Pic ) ( Pic )     Japanese bracket clocks started to develop at the end of the 17th century but did not become widely available until the later period of Japanese clockmaking, after 1800. Spring-driven Japanese bracket clocks vary in size from about 3 1/2 to 16 1/2 inches high, most commonly 5 to 9 inches. They have all the characteristics of the late period: brass cases and movements, flat bells, calendars, revolving chapter rings, fixed hands, balance wheels, and decorative, turned, corner pillars. Bracket clocks came in wooden cases and could be lifted in and out easily in the way that lantern clocks fitted into their hoods.

Brazing:
A method of bonding metallic surfaces with a more fusible metal or alloy. Unlike welding, in which the metals being joined are themselves most often melted together, brazing makes use of a bonding or filler metal of different composition and lower melting point than the metal being joined. This is the same as soldering, but as soldering is a term applied to many related processes it is normal to distinguish brazing from soldering. A common form of brazing brass or spelter consists of 50% zinc, 44% copper, 4% tin and 2% lead, although sometimes it might contain nickel, manganese or silicon.

Break arch:
( Pic )     A type of top for bracket clocks and longcase clocks which appeared about 1765 and is characteristic of the style of George Hepplewhite. The arch is incomplete, having a small ledge or step where it joins the sides of the case. Break-arch clocks usually had circular dials with brass bezels, but a number are known with silvered all-over, enameled or painted dials. Dials with a semi-circular top are also known as break arch.

Breastplate:
( Pic )     A curved plate or disc which is held against the body to support the pivoted end of a drill. Steady pressure can thus be applied to the drill while the breast plate is held on a cord hung around the neck.

Bretteluhr:
( Pic )     Meaning, 'board clocks' they date from the Biedermeier period in Austria, and were cheap clocks and popular with people of limited incomes. Bretteluhren occur with both weight- and spring-driven movements. The movements are quite small, usually about 4 inches high, and the backboard is 20 to 30 inches long. The back board is purely decorative, but provides a contrasting surface so that the observer can see if the pedulum is still swinging.

Bridge ( Clock ):
( Pic )     A bracket with two feet commonly used to support the pivot of an arbor outside the plates of a clock.

Briggs Rotary Clock:
( Pic )     Invented by John C. Briggs and patented in 1855. Many such clocks were made by the E.N.Welch Manufacturing Co. in the 1870s. The clock has a conical pendulum as the timekeeping element, a device first used by Robert Hooke in the 1660s for driving a telescope, although usually ascribed to the Dutch scientist Christiaan Huygens. Clocks using the conical pendulum have no escapement; the last wheel in the train carries an arm which rotates and turns the conical pendulum. Accuracy of timekeeping is less than with the conventional swinging pendulum because of the friction of the top support and the contact of the driving arm.

Broaches:
( Pic )     A long hardened steel tool, mostly tapered but also available in parallel form, usually with five cutting edges and used for enlarging pivot holes to size after drilling. Burnishing broaches, for finishing or burnishing holes, have smooth sides and no cutting edges. Broaches usually have a squared tapered tang for fitting to a drillbrace, tapwrench, wooden handle or pintongs. Some small broaches have long knurled integral steel handles.

Brocot Suspension:
( Pic )     A device fitted to a clock's pendulum suspension cock to allow rate adjustment from the dial. The pendulum spring is embraced by sliding brass chops or jaws threaded to receive a vertical screw which can be rotated by bevel wheels from a small square, usually fitted to the dial at 12 o'clock. This alters the effective length of the pendulum.

Bronze looking, Glass Shelf Clock:
( Pic )     The case consisted of a top slat on which was a stenciled design, applied with a bronze pigment, usually consisting of a bowl of fruit and cornucopia or a patriotic eagle and on the lower panel of the case door, a mirror or looking glass. This style of mahogany-veneer case contained a 30-hour weight-driven wooden movement and a painted wooden dial. It was introduced in 1828 by the firm of Jerome & Darrow and almost instantly became the most popular case style made in Connecticut, causing the demise of the more graceful pillar and scroll by 1830.

Buff:
( Pic )     A tool for grinding or polishing, mounted on a machine as a cone, disc or other suitable shaped piece of felt or leather, or of wood covered with felt or leather, or as a mop made of layers of cloth, string or other material to be charged with an abrasive or polishing compound. This is rotated in the machine at the appropriate speed for buffing.

Buff Treadle:
( Pic )     A stand on which is mounted a buffing machine, and the machine is operated by a wheel that is attached to a foot pedal. This treadle machine is operated by a pumping action of the clockmaker's foot.

Buffing, or mopping:
To grind or polish various surfaces by machine or hand using a buff charged with abrasive or polishing compound, in clock work normally metal surfaces, but latterly including plastics. In machine buffing the part to be polished or ground is held against the edge of the rotating buff or mop, fast-cutting buffs being used first, then finer, softer buffs to obtain the desired degree of finish.

Bulle Electric Clock:
( Pic ) ( Pic ) ( Pic )   The basic operating principle of the Bulle Clock, invented in the early 1900s by M.T. Favre-Bulle is identical to that of Alexander Bain's invented some 80 years earlier. Bain's sliding-bar contact is replaced by a silver pin and a fork lever with a contact on one side only, to give an impulse at every other swing. A solenoid with a high-resistance winding swings over a magnet with consequent poles (south-north-south). When current flows through the solenoid, the magnetic field thus produced interacts with that of the permanent magnet to give impulse to the pendulum. An isochronal spring is fitted to the pendulum to reduce the circular error which would result with changing amplitude as the cell voltage varies with temperature and use. Tens of thousands of these clocks were manufactured in France. Later models were housed in conventional clock cases as the novelty of the pendulum display wore off.

Burnishers:
( Pic )     A hand tool, generally a length of hardened steel, shaped and sized according to need, with a highly polished surface to burnish or polish metal to a smooth bright finish. Burnishers may be straight or curved, flat, oval or round, or formed with a burnishing foot and provided with a tang to fit in a wooden handle. A pivot burnisher or pivot file is double-ended or sided, one surface being finished as a very fine cross-grained file, the other being of the same shape but finished for burnishing.

Burnishing:
Bringing the surface of metal to a brilliant finish by friction, the action slightly compressing and hardening the metal surface but removing no metal. The metal surface to be burnished is first cleared of all file marks or scratches. The surface of the appropriately shaped burnisher must always be kept absolutely clean and highly polished, because the burnished surface can never be finer than the surface of the burnisher.

Bushing:
The remedy for a worn pivot hole, bushing provides it with a new bearing surface. The worn hole is opened further to round it up and to bring it to its original center. The new brass bush has a fine hole drilled in its center and is then turned to fit tightly into the new hole in the clock plate, and adjusted for length. Finally the bush is hammered or pressed into the hole and the new pivot hole in its center is broached out and burnished to suit its pivot. An oil sink or reservoir is cut on the outside of the new bush. Rebushing of a worn hole previously bused is more simple, for the worn bush can easily be replaced with a new one, and some clocks have removable bushes fitted at the time of manufacture.