Torque is a twisting force. Torque is applied to your watch stem when you wind your watch. You apply torque to unscrew the top of a mason jar. Torque caused rotation of a shaft, or it will set up a twist in a stationary shaft. It is generally expressed in foot pounds or inch pounds.
How is Torque Determined?
If a shaft connected to a 2 ft. lever or arm requires 2 lbs. of force to cause it to rotate, the torque would be 4 ft. lbs. The formula for torque is: T = R x S. Where R = Radius or length of the lever. S = Pounds Pull on Scale. Properly fastened threaded products achieve their holding power from the tension (or torque) that is derived from the mating of the external and internal threads subject to the elastic limit of the material.
What torque to apply is a generally asked question, but the answer depends on the variables of material, threads' class of fit, method of thread manufacture, and thread lubrication - if any. The table in the Technical Information PDF (link on this page) is offered as the suggested maximum torque values for threaded products made from Corrosion-Resistant metals. The table is only a guide. Actual tests were conducted on dry, or near dry, products. Mating parts were wiped clean. All values shown on chart except for Nylon represent a safe working torque; in the case of Nylon only, the figures represent breading torque.
See the Stahlin Enclosures Technical Information PDF link on this page for more technical specifics.
Stahlin Enclosures Technical Information - What is Torque? [pdf] View Link Stahlin Enclosures Complete Technical Information. [pdf Format] View Link