Punch and Punching. A punch is a short, stout piece of steel, or or iron steeled, used for stamping out pieces of metal, so as to make perforations in iron or other plates, for the insertion of rivets, screws, bolts, etc. In punching thick plates of metal, a powerful machine, consisting of a long and massive lever, worked by an engine, is generally used in considerable works; but as such machines are only in the possession of the comparatively few who require work of the kind to be well and expeditiously done, a simple and cheaply-constructed instrument for the purpose becomes an important appendage to the workshop; and such an instument we here present to the reader, which has been long and advantageously employed by Mr. J. R. Hill, of the Westminster Road. Fig. 1 shows a side view of the machine, fastened on an anvil a, by a cutter-bolt b. Fig. 2, a bird's-eye view of the same. Fig. 3, a section of the punching-hole, showing a part cut out for the pieces to fall out; pp is a plate to be punched; the back end of the lower part of b is furnished with a T piece, each end of which is turned up and tapped for the reception of a centre screw.
On these centre screws hangs the guide-arm c, which is also T shaped; the other end of this guide-arm has a hole c, just the size of the point of the punch to be used: in order to bring this hole to coincide with the lower one, it is only necessary to lengthen or shorten the arm, by bending it a little more or less, and turning the screws a little either way, which must be granted is much easier than adjusting a punch sliding in square holes, guides, etc. The set screws are also furnished with a nut each, to set them fast when adjusted. The reason for making it so long is, that any width of plate may come inside the holes. It is scarcely necessary to add, that a common rod-punch is used with its point only filed up to fit the hole.