Page:The American Cyclopædia (1879) Volume III.djvu/372

366 BRUSH secured by saturating their ends with glue or pitch. Other brushes are made for the most part by inserting little tufts of bristles into holes bored in rows into a stock of wood, bone, or ivory. The bristles are in some kinds se- cured by dipping their root ends into hot pitch, winding a piece of string round these ends, then dipping them again, and quickly intro- ducing them with a twisting motion into the holes, where the pitch soon sets, and holds them. Many brushes, as hair brushes, and in- deed most of those made with tufts which are not too large, are made by drawing the bristles, which are doubled in the middle, through holes and fastening them on the back with wire. The process of drawing and fastening the bris- tles is commonly performed by women. They sit around a table, each with a clamp attached to its edge for holding the stock-board, and each supplied with a fine flexible brass wire which is held in the right hand, and an apron full of bristles. A loop of the wire is passed through a hole in the stock, and a number of bristles being laid in it, the wire is pulled tight, causing the bristles to double and be drawn into the hole. The same process is repeated with the next hole, and so on, until all are filled with bristles, which are held tightly in their places by the wire. They are then clip- ped by a pair of shears gauged to cut the length of bristles required. If the bristles are very long, the clipping is done as each row of holes is drawn. Persons skilled in this process have drawn as many as 500 tufts in an hour ; but 100 an hour is a more common rate. In brush- es that are to be exposed to acid liquors, that would corrode brass wire, as the stopping brush used by hatmakers, a cord is substituted. The brush is finished by gluing a thin veneer upon the back of the stock, which covers over and protects the wire. A process for making hair brushes is employed by the Florence manufacturing company, by which much labor is saved. The brush, the stock of which is composed of what is known as hard rubber composition, is made in a die, and the opera- tion, after the adjustment of the bristles, is performed in a few moments. The die is composed of two parts, the cover and the base. In the cover there is cut whatever device or ornament the back of the brush is intend- ed to receive. In the base there are holes of a depth to correspond with the length of the tufts which are exposed after the brush is finished. The process commences by fill- ing the holes with bristles, which have been cut by a gauge as much longer than the depth of the holes as it is desired to have them pene- trate the back of the brush. The upper part of the die is then covered with a sufficient quantity of plastic rubber composition, when it is adjusted to its fellow and the die is placed in a screw press and subjected to great pressure. After hardening, which takes place in a few minutes, the brush is removed, perfectly finish- ed, having the tufts firmly held. An ingenious machine for making flat brushes, the invention of Oscar I), and . 0. Woodbury of New York, was patented in April, 1870. It folds the tuft of bristles at the middle, and secures the knuc- kle by a wire passed through and wound spiral- ly round it. It is then forced with a twisting motion into the hole in the back prepared for FIG. l. it, and firmly secured. The machine will fill from 60 to 80 holes per minute. The back of the brush is made of one piece of wood, and the holes may be bored into it (not through it) by a gang of bits. It is not necessary that the holes be bored at certain distances, or with great regularity, because by an ingenious ar- rangement the hole to be filled is brought im- mediately beneath the cone which delivers the tuft. The bristles are fed from a metallic comb in the manner shown in fig. 1, the tuft being separated at the point A. It is doubled by the plunger B, and forced down into the cone, as shown in fig. 2. The wire is passed through the bend and twisted around by the rotary motion of the plunger, which passes into a hol- low cone, having a spi- ral groove which gives direction to the wire and secures it. The plunger continues to descend with a twisting motion until it reaches the back of the brush, and screws the tuft into it, as shown in fig. 3, when it rises and receives an- other tuft, which it ma- nipulates as before. The delicate brushes, called also hair pencils, used for water colors, are made of the hair of the camel, goat, badger, sable, squir- rel, &c., by binding a bundle of them together after being carefully ar- FIO. 2.