Book Description

Excerpt from Toolmakers Kinks Who has not Often seen a machinist pick up a bar Of metal covered with rust and dirt and wonder whether it was tool steel or machine steel. Now, there are a number of means of finding this out, but the emery wheel test, while not a particularly refined method (it will not tell you everything about a steel) is as quick and handy as any. To test a piece, touch it lightly against a dry emery wheel and observe the sparks as they strike the frame of the machine. A high-carbon steel gives a spark which appar ently bursts into a brilliant star-like point of light when it strikes against anything. The spark from a low-carbon steel is, on the contrary, merely a dull, incandescent particle. It is said that all the air-hardening steels give a very red spark. By the way, some air-hardening steels can be greatly improved by heating to a bright. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This 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.