The speed of the lead screw will be

Question

It is required to cut screw threads of 2 mm pitch on a lathe. The lead screw has a pitch of 6 mm. If the spindle speed is 6 rpm, then the speed of the lead screw will be                                                   

(a) 10 rpm                       (b) 20 rpm

(c) 120 rpm                     (d) 180 rpm