To prescribe simulative contact pressures in benchtop wear tests on materials and lubricants for threads of lead screws, it is necessary to understand how applied load is distributed over those threads. While in threaded fasteners it is known that the first engaged nut thread carries the greatest load and experiences the highest contact pressure, in a lead screw application with considerable sliding this most heavily nut thread will correspondingly wear most rapidly. This suggests instead an eventually uniform steady-state load distribution over the nut threads that should be considered in arriving at a lower contact pressure for simulative wear testing. A model is therefore developed for this coupled evolution of thread load distribution and wear.
