Excerpt from Screws and Screw-Making: With a Chapter on the Milling Machine Small screws - by which we mean those under Jin. diameter - are not comprehended by the Whitworth nor the Sellers systems. These small screws, which are chiefly employed in horological mechanism, were taken in hand by the Geneva Society of Arts, and a remarkably thorough system was tabulated by Professor Thury, which is now adopted in the horological trades on the Continent. On the recommendation of a committee of the British Association for the Advancement of Science, Professor Thury's system has been adopted in the United Kingdom. We have printed all these reports unabridged, and their perusal will explain all that has been done in the way of theorising on screws. The table of wheel trains to cut various thread-rates by the aid of guide-screws, extends further than any one we have met with. It includes nearly 1,000 thread-rates, ranging from the coarseness of one turn in sixteen inches to the fineness of one hundred turns per- inch. In the practical part we have endeavoured to give a clear and concise explanation of the methods and processes of screw-making. Many illustrations are shown of the most important machinery used for the purpose, which we are continually making. With every confidence that this treatise supplies a want hitherto not fully met, we offer it to all who are interested in mechanism of which screws form an integral part. We shall be at all times willing to correspond with any reader who may require information not given, and shall be glad to hear of any error in figures that, even with the greatest care, may have remained undetected in the tables, so that correction can be made in a future edition. 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.