Gears

The number of revolutions can be changed by using gears which are shifted by clutches. Clutches are usually operated by levers. Gears are fabricated with sliding structure. Consider the case of a three stepped gear. Here three different numbers of revolution possible. Gears here connected with each other and they do not generally suffice. In a lathe, main drive consists of a number of two or three stepped gears connected with each other. These gears are assembled in an oil-tight casing. Gears should be engaged only at stand-still or at slow-down. Engaging time for gears can be reduced by braking or automatic clutches and preselecting devices.