Cold-Heading (Classic Reprint)

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Excerpt from Cold-HeadingIf we should cut off a piece of 178-inch diameter copper wire about 1 inch long, stand it on end on a hardened steel block, as shown at A, in Fig.' 2, and strike it squarely on top with a heavy hammer, we would upset the piece as a result of the blow, causing it to bulge con siderably at the center, the amount depending upon the force of the' blow, leaving it with an appearance as indicated at B, Fig. 2. Con tinuing our experiments, if we take another -inch piece of copper wire, 1 inch long, as before, and drop it into a -inch hole in a hard ened steel block, allowing a section inch long to extend above the surface of the block, as at C', Fig. 3, and strike the end of this piece a square blow with the same hammer, the piece will assume about the appearance indicated at D, in Fig. 3. The projecting section will be bulged'as before, but the part of the blank remaining within the block must necessarily retain its original shape, as it is confined in all di rections. Continuing our experiments still further, if we take a new blank of the same dimensions and insert it in the same block as be fore, but infplace of the ¿at ended hammer we use one with a cup shaped depression turned in its face, as shown at E, Fig. 4, and strike the blank a hard blow squarely upon the projecting end, the end of the wire will necessarily take on the appearance indicated at F, Fig. 4. The blankmust assume this shape because the part under the head is confined within the lower block and the head section is guided in its bulging by the cup-shaped depression in the hammer with which the blow is struck.About the PublisherForgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.comThis book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully, any imperfections that remain are intentionally left to preserve the state of such historical works.