A machine vice whose length of the handle is 150mm and the coefficient of friction for thread and collar are 0.15 and 0.17 respectively has a force applied at handle of 125N. Also the outer and inner diameters of collar are 55mm and 45mm respectively. Find the overall efficiency if nominal diameter=22mm and pitch=5mm.

Correct Answer: 12.18%
Efficiency= W l/2π(M₁+M₂) where M₁=2.286W . M₂=4.25W , l=5mm, W=2868.73N .