A practical course in horology - PDF book by Harold Caleb Kelly

A practical course in horology 

A practical course in horology
a practical course in horology 

The art of horology unquestionably ranks among the most wonderful of the mechanical arts. One can only marvel at the diminutive size of the modern wristwatch and the accuracy of the machines by which the duplicate parts are made. Production and improved manufacturing methods have also changed the repairman's approach to horology. Duplicate parts are available, so the horologist is seldom called upon to make a part. 

, since the sizes of watches have been reduced, new tools and improved methods are essential to good workmanship. One must develop greater skill in fitting staff to small, uncut balance wheels, in adjust- ing small escapements, and in handling the new, alloyed balance springs. The purpose of this book is to present the fundamentals of horology, both in theory and practice. Part 1 deals with wheel work and gearing, which involve the work of calculating the number of teeth of missing wheels and pinions and in determining their proper diameters. Principles of escapement design and an analysis of the balance and spring are given considerable space. 

Part 2 treats repair methods, in which the making of a balance staff and the adjustment of the escapement are given more than the usual space allotted to these subjects. Part 3 is concerned with the adjustments to position, isochronism, and temperature, factors that may be called the finishing touches of the horological profession. 

The author is indebted to T. J. Wilkinson and C. E. DeLong for the reading of parts of the manuscript and for helpful suggestions. 

The chapter on wheel work is based on a system by Jules Grossman, late director of the horological school of Locle. It is hoped that this work will contribute some small part toward the development of a generation of capable and well-equipped horologists.


"TIME'' Poem, by Laurens L, Simpson . . 7
Preface 9
ONE. Wheel Work 13
TWO. Gearing 32
THREE. The Lever Escapement 39
FOUR. The Controlling Mechanism ... 52
ONE. Train Problems 62
TWO. Jeweling 6^
THREE. Making a Balance Staff 72>
FOUR. Pivoting 85
FIVE. Fitting Balance Springs 88
SIX. Escapement Adjusting 100
SEVEN. Cleaning and Oiling 124
ONE. Preliminary Notes on Adjusting . . 128
TWO. Position Adjusting 140
THREE. Adjustment to Isochronism . . . .150
FOUR. Adjustment to Temperature. . . .156
FIVE. Practical Work of Adjusting . . . 159
Glossary of Terms 173
Bibliography 182
Index 185

Author: Kelly, Harold Caleb
Publication Date:1944

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