PREFACE TO ENLARGED EDITION
This thoroughly revised and enlarged edition of Machinery's Handbook contains many standards, tables, rules, formulars and practical data, systemically collated since the publication of earlier editions. The work is enriched by this new material, most of which is published because of repeated requests from engineers, shop executives, and skilled workmen, who have indicated its need in a standard work of reference that is relied upon to contain all the essential working data and fundamental principles of the machine-building industries.
To indicate concisely the extent of this revision, the more important changes may be summarized: The total number of pages has been increased from 1400 to 1592; there are 230 pages of entirely new matter; 97 new tables; 77 new illustrations; 35 revised tables; 55 pages of revised text, exclusive of new material; and several hundred smaller but important changes.
The publishers here express their appreciation and thanks for the cooperation of many friends in the machinery industries, who have assisted in this work of revision by offering practical suggestions of constructive criticisms of former editions. Since Machinery's Handbook was first published in 1914, all letters containing suggestions or material for its improvement have been filed systematically, and have been most valuable in the work of editing this new edition.
For more than ten years, Machinery's Handbook has been a standard reference work for the machinery industries, and the publishers have spared neither labor nor expense to keep it abreast of mechanical progress.
This preface would be incomplete without the names of the men who compiled and edited this book. For the capable and long-continued labors bestowed on this work by Erik Oberg, editor-in-chief, and by Franklin D. Jones, his associate, the publishers here express their sincere thanks and appreciation.
