File:EB1911 Typography - Wicks Rotary Type-casting Machine.jpg

English: The Wicks Rotary Type-casting Machine adopted a new principle which is able to produce finished types, ready to be dispatched to the printer without any inspection or treatment beyond packing, at a continuous rate of 60,000 an hour. It consists of a horizontal mould wheel, 20 in. in diameter, contained in the casing D (fig. 6), in which are cut 100 radial slots, each having a matrix at its inner end. These slots thus form moulds, and are of varying width according to the letter each has to cast. Each wheel can only produce type of the particular body for which it has been cut, but by changing the matrices the moulds can be made to cast any description of face capable of being received upon the body. The wheel is rotated once in every six seconds, so that the slots are successively presented to a jet of molten type-metal, which is pumped from the metal reservoir A by a pump B of special construction and forced out at high pressure through a nozzle under the shield C. As soon as any particular slot has passed the jet and been filled with metal, a cam-action comes into play and gradually pushes out the formed type. This operation is completed in half a revolution, the ejected type being taken up by carriers mounted on a continuous chain E, which is moved along exactly in step with the wheel. The carriers, which are of different sizes according to the particular letters they have to hold, are raised by a cam-action as they come opposite the slots to receive the types, but fall again at the point F, depositing the letters at the end of the race Each successive type thus dropped pushes its predecessors farther along the race until when the row contains 200 types—the product of two revolutions of the wheel—an attendant lifts the whole series off and places them on the plate H, one row below the other. Since the sequence of the letters is of course the same in each revolution, the result is that each vertical line on the plate consists of the same character, and each sort can be easily removed and packed in any required form for despatch to the printer. As soon as each slot has been emptied of its type, another cam begins to draw in the matrix towards the centre of the wheel, so that it is in as far as it can go by the time the slot is again opposite the jet. To prevent a type from being drawn back with the matrix, the bead-cam K engages with the nicks which have already been formed on the front of the the bodies by the operation of the machine. To ensure trueness and accuracy in the product, the conditions under which casting is conducted are maintained as uniform as possible. The composition of the type-metal alloy is kept constant; the temperature of the molten metal is carefully regulated by the aid of a pyrometer to about 800° F., so as not to volatilize the antimony it contains; the pumps work up to a pressure of 900 ℔ to the square inch, and by the interposition of a reducing valve deliver the metal at the nozzle at a constant pressure of 200 ℔; and the moulding slots are maintained at an equably cool temperature by an elaborate system of water circulation.