Correct option is B
Square threads are used in screw jacks due to their high efficiency in power transmission and their ability to handle large axial loads. The thread design minimizes friction and ensures smooth, reliable operation under heavy loads.
Key Characteristics of Square Threads:
· Flat crests and roots.
· Perpendicular sides, providing maximum strength and reduced wear.
· High mechanical efficiency due to low friction.
Applications of Square Threads:
· Screw jacks for lifting heavy loads.
· Lead screws in precision machines.
· Heavy-duty vices.
The Acme thread used for lead screw. The angle of across thread is 29°.
