The gears evolution from wood to metal has seen thousands of different applications from heavy artillery catapults to precise gearbox of racing cars. In each era of inventions and developments gear design also experienced so many design modifications to make it the most precise and reliable transmission system any mechanical industry ever had. In this book a gearbox of lathe machine is taken for study. The gears of the lathe machine are considered for the study to typically modify the present gear design to extract better improved results from the same gearbox. The gear design modifications...