Broaching Press.—Broaching consists in forcing cutters through keyways or apertures, to dress their sides to shape.
Fig. 1873.
In [Fig. 1873] is represented a broaching press. Its driving gear which is within the box frame is so constructed that it may be started and stopped instantly, notwithstanding its heavy fly wheel.
[Figs. 1874] to [1877] represent the method of cutting out a keyway by broaching.
Fig. 1874.
In [Fig. 1874] a represents the end of a connecting rod having three holes, b, c, and d, pierced through it, their diameters nearly equalling the total finished width of keyway required. The punch d′ is first forced through, thus making the three holes into one.