The scarcity of the literature on Presses and Press Tools is in itself sufficient justification for the publication of these articles, which appeared originally, at intervals, in the columns of The Practical Engineer, and are now published in book form at the request of many readers.

The production of tools for the working of sheet metals is a distinctly separate branch from that of engine-fitting and general machine work. It is therefore difficult for an engineer to thoroughly grasp the work of the press-tool maker, unless he has had an opportunity of closely watching the tool work in progress and the subsequent operations performed by the tools in the production of numerous articles made from sheet metals.

This difficulty is largely due to the many technical points of detail connected with the processes through which an article may have to pass before reaching its final stage, which will become obvious upon reading Chapter XI (Drawing And Re-Drawing).-Drawing and Re-drawing-and Chapter XIX (Press Tool-Setting). on Tool Setting.

The subject embracing, as it does, many industries, including a vast number of separate processes, no systematic treatment has been attempted. As far as possible each section has been taken separately, and where necessary to a complete and thorough understanding of a point under consideration, either a little recapitulation has been deemed advisable, or reference made to the chapter or section where the particular point has been previously mentioned.

The original articles were the result of many years' work, and study of a business which plays an important part in many British industries, and it is hoped that these collective notes in book form will be found useful to engineers, mechanics, manufacturers, and to young technical students, assisting them to overcome some of the difficulties which they may meet with in technical schools and workshops. A few remarks in reference to the machine tools to be found in every machine shop have been included, to enable the younger readers to better understand the matter contained in those chapters which refer to the manufacture of press tools.

At present very little seems to be known by mechanics in the workshops concerning the work done in either a Fly Press or Drop Stamp. It is therefore hoped that the special chapter devoted to the following subjects-work done in Copying Press, Fly Press compared with the Screw Press, work done by the Stamp Hammer, the reasoning regarding the Hammer Blow-will be readily followed by the student and practical mechanic, who may not have sufficient scientific and mathematical knowledge to follow the reasoning of the more advanced text-books on the subject.

The illustrations used are of a special character, and do not represent every possible type of Power Press. Those selected may be regarded as being good practical examples of modern machines and calculated to be useful to the greatest number of those who are engaged in sheet-metal working industries.

Calculations and definitions have been introduced to enable practical mechanics to readily grasp the point under consideration with the least possible calculation, and at the same time more accurately and quickly than by" rule-of-thumb" methods.

Any suggestion relating either to improvements or additional matter calculated to make this work more complete will be gladly and carefully considered, with a view to the revision'of future editions.

The Author takes this opportunity of thanking his numerous friends for their valuable assistance, specially mentioning Mr. Daniel Smith, whose information regarding both machines and tools has greatly assisted him in his work. The Author's best thanks are also due to Messrs. Buck and Hickman, Loudon; Daniel Smith and Co., Wolverhampton; John Rhodes and Son, Wakefield; Taylor and Challen Ltd., Birmingham; W. H. Ward and Co., Birmingham, who, by their kindness in placing at his service electros of special machines have enabled the text to be illustrated so as to make it more readily understood.

R. B. Hodgson.

54, Westfield Road, King's Heath. Birmingham. 1903.

Errata

On page 63, line 11, instead of "the limiting diameter, etc.," read

" The minimum diameter of any bole in a plate t inches thick of any material is t x 4 x the limiting shearing strew ., crushing stress of punch

On page 94, fig. 96, dimension of base should read "4 3/4 in.," not "4 ft 3 in."