Watch and Clock Escapements A Complete Study in Theory and Practice of the Lever, Cylinder and Chronometer Escapements, Together with a Brief Account of the Origin and Evolution of the Escapement in Horology   By: Anonymous

A Complete Study in Theory and Practice of the Lever, Cylinder and Chronometer Escapements, Together with a Brief Account of the Origin and Evolution of the Escapement in Horology

Compiled from the well known Escapement Serials published in The Keystone

Nearly Two Hundred Original Illustrations

Published by The Keystone The Organ of the Jewelry and Optical Trades 19th & Brown Sts., Philadelphia, U.S.A.

1904

All Rights Reserved Copyright, 1904, By B. Thorpe, Publisher of the Keystone.

PREFACE

Especially notable among the achievements of The Keystone in the field of horology were the three serials devoted to the lever, cylinder and chronometer escapements. So highly valued were these serials when published that on the completion of each we were importuned to republish it in book form, but we deemed it advisable to postpone such publication until the completion of all three, in order that the volume should be a complete treatise on the several escapements in use in horology. The recent completion of the third serial gave us the opportunity to republish in book form, and the present volume is the result. We present it to the trade and students of horology happy in the knowledge that its contents have already received their approval. An interesting addition to the book is the illustrated story of the escapements, from the first crude conceptions to their present perfection.

CONTENTS

CHAPTER I.

THE DETACHED LEVER ESCAPEMENT 9

CHAPTER II.

THE CYLINDER ESCAPEMENT 111

CHAPTER III.

THE CHRONOMETER ESCAPEMENT 131

CHAPTER IV.

HISTORY OF ESCAPEMENTS 153

CHAPTER V.

PUTTING IN A NEW CYLINDER 169

INDEX 177

WATCH AND CLOCK ESCAPEMENTS

CHAPTER I.

THE DETACHED LEVER ESCAPEMENT.

In this treatise we do not propose to go into the history of this escapement and give a long dissertation on its origin and evolution, but shall confine ourselves strictly to the designing and construction as employed in our best watches. By designing, we mean giving full instructions for drawing an escapement of this kind to the best proportions. The workman will need but few drawing instruments, and a drawing board about 15" by 18" will be quite large enough. The necessary drawing instruments are a T square with 15" blade; a scale of inches divided into decimal parts; two pairs dividers with pen and pencil points one pair of these dividers to be 5" and the other 6"; one ruling pen. Other instruments can be added as the workman finds he needs them. Those enumerated above, however, will be all that are absolutely necessary.

[Illustration: Fig. 1]

We shall, in addition, need an arc of degrees, which we can best make for ourselves. To construct one, we procure a piece of No. 24 brass, about 5½" long by 1¼" wide. We show such a piece of brass at A , Fig. 1. On this piece of brass we sweep two arcs with a pair of dividers set at precisely 5", as shown (reduced) at a a and b b . On these arcs we set off the space held in our dividers that is 5" as shown at the short radial lines at each end of the two arcs. Now it is a well known fact that the space embraced by our dividers contains exactly sixty degrees of the arcs a a and b b , or one sixth of the entire circle; consequently, we divide the arcs a a and b b into sixty equal parts, to represent degrees, and at one end of these arcs we halve five spaces so we can get at half degrees.

[Illustration: Fig. 2]