MACHINE FOUNDING. Various attempts were made during the early part of the nineteenth century to cast types by machinery. The first sueeessful machine for this purpose was devised by David Bruce, Jr., of New York. and was pat ented in 1838. As subsequently improved, this machine was extensively used in American type foundries and was introduced into Europe. Brief ly described, the Bruce type-casting machine con sists. first, of a small melting-pot, which contains the molten metal, and is placed over a small fur nace. In the interior of the pot is arranged a foreing-pmnp and valve for admitting the metal under the piston, and also for preventing the re turn of the metal into the mass in the pot when the piston is depressed, and thus securing the full force exerted upon the piston being trans mitted to the molten metal under the piston, and forcing it through a narrow channel leading from the bottom of the chamber in which the pis ton works to the outside of the pot. where a nipple is inserted, with a small hole through it, com municating with this narrow channel. Against this nipple the mold in which the type is formed is pressed at the moment at which the piston de scends, and so receives the molten metal that forms the type.
The second part of the machine is that which carries the mold, and to which the mold is firm ly bolted. The mold is similar to the old hand mold, but modified to suit the machine; it is much stronger; the 'jets' are shorter, and the orifice by which the metal enters is smaller, so that it may be brought exactly coincident with the small hole in the nipple in front of the pot. The mold—as the old hand-mold—is made in halves; one of the halves is firmly bolted to an arm which, by cams and levers, is made to oscil late, and carry the mold to and from the nipple in front of and above the pot ; the other half of the mold is bolted to another arm, which, by a peculiarly formed hinge, is attached to the first arm, so that the two halves of the mold may be made to open and shut upon each other like the lid of a snuff-box; and so both sides of the mold oscil late together to and from the nipple in the pot from which they receive the molten metal. The
operation of the machine is as follows: The pis ton being raised in the chamber of the pump, and the chamber being supplied with metal through the valve, the mold is brought against the nipple; the valve closes to prevent the metal being forced back into the pot ; the piston descends, and forces the metal through the narrow channel into the mold; the mold then recedes from the nipple, and in receding the two halves separate from each other and eject the type; the mold again ap proaches the nipple, and in approaching the two halves close together, and are ready for another operation. A blast of cold air is directed upon each mold to keep it cool.
The types produced by the Bruce machine as built previous to 1868 had to be dressed by hand, but in that year "Mr. Bruce invented an apparatus for dressing the type mechanically which could be applied to his casting machine. Bruce's im proved machine was followed by one designed by Henry Barth, of Cincinnati, 0., in 1SSS. This machine casts the types, finishes them, and pro duces them set up in lines ready for inspection. The output of the most recent type-casting ma chines varies from 100 to 140 types per minute, according to the size of the letter. In conclusion, mention should be made of the type punch cut ting machine, invented by L. B. Benton, which operates on the principle of the pantograph and produces from one pattern letters of any size desired.
For the history of English type founding, con sult Reed, History of the Old English Lotter Founders (London, 1S87), and De Vinne, His toric Printing Types (New York, 1886). See TYPESETTING MACHINES.