by Harold Hall

Published by Special Interest Model Books Ltd, Dorset England

150 x 210mm


ISBN 978-185486-238-9

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Extract from back cover of book:

Faced with the prospect of machining a gear or gears for a project, many model engineers will be discouraged and will turn elsewhere for their next model. This need not be so, for the principles underlying gear cutting and many other aspects of engineering where an accurate division of circles is required are explained in depth in this book.

It covers the subject of Dividing, dealing with the many methods that can be adopted: from simple applications without specialised equipment to the use of a semi-universal dividing head and a rotary table. The mathematical aspects of dividing are also covered but at a level that will be understood easily by a model engineer. Dividing equipment is relatively expensive, so two fully-detailed designs are included for dividing heads: a basic unit and the equivalent of a commercial semi-universal head.

About the Author - Harold Hall has established his reputation as a mentor to tyro engineers through the pages of Model Engineers' Workshop of which he was the editor for a number of years and through his other two books in this series, Lathework - A Complete Course and Milling - A Complete Course.

Photos: Black & White

Units of Measurement: Metric


Chapter 1 - An introduction to Dividing

Chapter 2 - The Machinery
Discusses the major items of equipment, Dividing heads, Rotary tables, Indexers, etc.

Chapter 3 - The Methods
Explains how to use the equipment in Chapter Two to achieve the required result. Also explains though how even complex dividing can be achieved using no other equipment than that normally found in the workshop, typically the lathe and milling machine.

Chapter 4 - The Mathematics
Whilst the tables provided with a dividing head, or those published in this book, will provide the information for most applications, occasionally recourse to calculation may be necessary. This chapter explains the process, fortunately, the mathematics is not complex.

Chapter 5 - Holes on a Pitch Circle Diameter (PCD)
Explains the mathematics for placing holes on a PCD using a milling machine's X and Y table movements and their calibrated leadscrew dials. Also shows how using a computer spread sheet program can be used to limit considerably the work involved.

Chapter 6 - Shop Made Simple Dividing Devices
Some simple devices that will enable dividing activities without the need for a dividing head.

Chapter 7 - Shop Made Basic Dividing Head
A simple dividing head that is easy to construct, and for most, will be adequate for all the dividing tasks required in the workshop.

Chapter 8 - Shop Made Full Function Dividing Head
A dividing head that is more adaptable than a commercially available semi-universal head and providing a wider range of divisions. It is not over complex to make and would be a very satisfying project to complete.

Chapter 9 - Shop Made Lining Tool
Engraving a dial with its different length lines is made easy with this lining tool. It is also an interesting project to construct.

Chapter 10 - Prime Numbers
Prime numbers and their uses explained and listed.

Chapter 11 - Tables
Tables for a wide range of dividing head ratios and division plate hole numbers are included. These should make the need for calculation a rare occurrence.