Fig. 218.
Fig. 219.
(409) When the short lengths of leather are obtained, they are cemented along their bevelled edges with a special cement, and are firmly pressed together by a light screw press. In this way a sheath is formed large enough to draw over the boss of the roller, but a little longer than it. The covering so formed is then pulled over the roller by the machine shown in Fig. [218], which is the type commonly used, however the covering is prepared. The leather tubes are placed upon the spring A, consisting of a thin cylinder of sheet metal, which is divided into several ribs as shown. The roller to be covered is placed end up on the recessed stop B, and by a revolution of the handle C the spring is drawn over the roller leaving the sheath behind it. The special construction of the spring enables it to pass over the boss of the roller and draw out of the leather tube. A small portion of the tube projects beyond the boss at each end, and this it is necessary to wrap over so as to firmly secure the covering. This operation is effected by placing the roller in suitable holders, and subjecting the projecting ends of the tube to an end pressure. For this purpose the rollers are revolved by being brought into frictional contact with a rotating cylinder. The most complete machine for this purpose is shown in Fig. [219]. The rollers are held in arms B B on the cylinder A, the bearings or steps in the arms being specially constructed, so as to provide a very thin surface to sustain the roller. The ends of the leather being cemented, they are turned over by means of a rod or bar, and are thus perfectly secured. A fan F is placed under the hood of the machine, and takes away any fumes produced by the process of ending. The cylinder is made of thin steel, and is run at from 700 to 1,000 revolutions per minute.
Fig. 216.
Fig. 217.