Question

Metric thread of 0.8 mm pitch is to be cut on a lathe. Pitch of the lead screw is 1.5 mm. If the spindle rotates at 1500 rpm, the speed of rotation of the lead screw (rpm) will be

• A. 800

Answer 1

The correct option is A 800
$\text{Pitch of thread,}{P}_t=0.8mm$

$\text{Speed of spindle,}{N}_t=1500rpm$

$N_s\times P_s\times Z_z=N_t\times P_t\times Z_t[\therefore Z_s=Z_t=1]$

$N_s\times 1.5\times 1=1500\times 0.8\times 1$

$N_s=800rpm$