Question

 Back gears are used in the centre lathe for:

(a) effective reduction in spindle speed

(b) increase in spindle speeds

(c) facilitating a wider range of speeds

(d) spare purpose

1. (a) and (b)
2. (a) and (c)
3. (b) and (c)
4. (a) and (d)

Answer 1

Correct Answer - Option 2 : (a) and (c)

Explanation:

Back Gears

• The back gear mechanism is an additional part of the belt drive lathe.
• It is used to obtain a slower & wider range of spindle speeds, back gear disengagement & engagement.
• As the name implies, “back gear” is a gear mounted at the back of the headstock.
• The back gear consists of four gears located at the back of the headstock which reduces the speed of stepped pulley in the headstock.
• When the back gears are engaged this pulley is disconnected from the headstock spindle.
• When the back gears are disengaged this pulley is connected to stock and drives it directly.