Main type-setting machines are:

*  LINOTYPE and LUDLOW (slug-casting -- entire line on one body)
*  MONOTYPE (lines justified, with each character cast on separate body).

The Linotype was invented by Ottmar Mergenthaler (1854-1899) a watchmaker of Wurttemberg (Germany), who emigrated to America in 1872.
While developing a process of type-writing with a facsimile of printers' type - to do away with typesetting (work was multiplied by lithography), he realised the uselessness of the project and conceived another idea, that of female matrices for casting.

This eventually led to the inception of the Linotype in 1886, from which the present models have been developed.
Matrices are released from a magazine on manipulation of key buttons and travel down a moving belt to an assembler box.
Spaces are compound steel wedges which, just prior to the casting operation, spread line to full predetermined width.
Matrices and spacebands are automatically returned to magazine and spaceband box respectively, while slug is trimmed to depth, ejected through trimming knives for accurate body dimensions, and delivered to galley.
Standard type metal for the Linotype is tin, antimony and lead in ratio 3:11:86. Best results are obtained with a casting temperature of 515 to 565 degrees F.

The principle of the Monotype was invented by American, Tolbert Lanston (1844-1914).
The machines were put on the British market in 1897 by the Lanston Monotype Corporation Limited.
The company purchased from the American owners the patents for Great Britain, the Continent, British Possessions (excepting Canada), and the remainder of the  Eastern Hemisphere.

This company was later re-named The Monotype Corporation Ltd., and all machines intended for use in territory controlled by the company were manufactured at Redhill, Surrey, UK.
Monotype composition is achieved on two separate machines, the keyboard and the caster. The keyboard is arranged on the type-writer principle, (QWERT, &c.) and as the operator depresses the keys, he causes code holes to appear on a spool of paper. This paper is later passed to the casting operator who uses it to cast the type. The perforated tape may be stored for further casting, thus eliminating need for holding type. The Duplex keyboard permits copy to be perforated in duplicate, or in two different sizes of type.
During the casting operation, the code holes cause the correct letters to be cast and ejected at the rate of 150 per minute, arranged correctly in lines of a given measure.
Range of machine is from 4.5 pt. to 24 pt. To measures up to 60 pica ems.
The Monotype Super Caster will cast Display type up to 72 points as well as leads, rules, block-mounting material, strip furniture, &c. The Monotype machine is more flexible with regard to metal requirements than other type-casting machines. Three distinct grades of metal in use all give satisfactory results:
1. The same metal as used in linotype machines thereby retaining one formula for convenience. 2. Known as 'Standard Formula' - the tin and antimony percentages have been increased to 8% tin, 16% antimony and 76% lead. 3. 'Job Type'metal whose hardness approximates that of foundry type. The formula ranges from 10 to 12% tin, 20 to 23% antimony and the balance lead.
For supercaster work requiring a very high grade of metal for display type, a formula of 12:23:65 will be found satisfactory. The liquidus temperature of this alloy is considerably higher than other mono alloys, and special care should be employed in casting to maintain a homogeneous metal in the pot to prevent blockages in nozzles.

Ludlow was first installed in England in 1923, at that time limited to three faces, -- Caslon, Cheltenham and Bodoni. Original models were gas-heated with air-cooled moulds. Later models were electrically heated, with water-cooled moulds, and an automatic metal feeder, keeping pot always full, with an even temperature. The Ludlow is used mainly for jobbing and display work.

It casts slugs on either 6-point or 12-point body, with face range from 4-point to 144-point. There are two popular grades of metal used in Ludlow machines, the most popular being 4-11-85 (as Linotype). The other alloy, 6-12-82, is a strong alloy, having more fluidity than 4-11-85, and for this reason will produce a good typeface with sharp definition.
The complete Ludlow unit comprises: The necessary matrices of type faces; spaces; matrix-assembling sticks; the casting machine; super-surfacer for burnishing larger typefaces; trimmer saw for cutting slugs to required measure.
Matrices are gathered by hand and assembled in the Ludlow assembling-stick, which is graduated in pica ems. By arranging spaces, type will be eventually cast on any desired position in the slug, eg., front, centre, back.
Usual spaces are: 1-point, 2, 3, 4 and 6-point; 1 pica, 1.5, 2, 2.5, 3, 6, 9 and 12 picas.

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