Between V-threads and Square threads transmitting power of --- threads are preferred.

Explanation:

V Thread:

• V threads are one of the most widely used thread types.
• The thread angle in 60° and as their thickness at the base is equal to the pitch of the thread, they are comparatively stronger than square threads.
• They are easy to manufacture on large scale due to their simpler design.
• They are used in fasteners due to their high strength and low cost. 

Square Thread:

• Square threads have the highest efficiency as their flank angle is 0°.
• As their thickness at the base is half of the pitch length, their chances of failure are high due to lower strength.
• They are very difficult to manufacture and they are turned only on the lathe.
• Due to their higher power transmitting efficiency, they are used in jacks as power screws.

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