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Mechanical Engineering QUESTION #2468
Question 1
For Acme threads compared to square threads, which statement is CORRECT regarding power transmission efficiency?
  • Acme threads are more efficient due to their wedge-shaped tooth profile
  • Square threads are more efficient; Acme threads add extra friction due to wedging action of the thread angle \(\alpha\)✔️
  • Both have identical efficiency
  • Acme threads are self-locking; square threads are never self-locking
Correct Answer Explanation
Square threads are more efficient because the thread load is parallel to the screw axis. Acme threads require modifying friction terms by \(\sec\alpha\), which increases friction and reduces efficiency.