A single start square threaded power screw supports load of 30 kN which has outer diameter of 30 mm and a pitch of 8 mm. Maximum shear stress of 30 N/mm2 is induced in a screw body. Determine number of screw threads considering direct shear stress.

A single start square threaded power screw supports load

1.	A single start square threaded power screw supports  load of 30 kN which has outer diameter of 30 mm and a pitch of 8 mm. Maximum shear stress of 30 N/mm2 is induced in a screw body. Determine number of screw threads considering direct shear stress.
A.	3 threads
B.	2 threads
C.	4 threads
D.	None of the above
Answer» B. 2 threads