1.       Compare the tensile load capacity of a 5/16-18 UNC thread and a 5/16-24 UNF thread made of the same material. Which is stronger? Make the same comparison for M8 X 1.25 and M8 X 1 ISO threads. Compare them all to the strength of a 5/16-14 Acme thread.

2.       A 3/4-6 Acme thread screw is used to lift a 2 kN load. The mean collar diameter is 4 cm. Find the torque to lift and to lower the load using a ball-bearing thrust washer. What are the efficiencies? Is it self-locking?

3.       A 1 3/8-4 Acme thread screw is used to lift a 1-ton load. The mean collar diameter is 2 in. Find the torque to lift and to lower the load using a ball-bearing thrust washer. Whatare the efficiencies? Is it self-locking?