Thread damage can occur because of cross-threading, over-torquing and under-torquing. Cross-threading happens when the threads of two screwed together pieces are not aligned correctly. Cross-threading can result from insufficient or incorrect installation torque and can cause serious damage. Thread damage can also occur because of over-torque, which stretches the thread spacing. Thread damage can also occur from under-torque, which can result in loosening of the joint from vibration and thread damage. Using a torque wrench with careful installation can prevent thread damage.
Thread damage has been investigated and tested by J.E.I. Metallurgical many times. One of our recent maters is listed below.