Can any one offer a method or location of a method for determining the permissible axial load that can be applied to an internal thread? i.e. Take a nut and screw into it two bolts, one from either end so they meet in the middle of the nut, then apply a tension force across the two bolts. How much tension can be applied before the thread brakes? The nut in this case is not stamped with its rating or grade etc. Its of a known material with a known tensile and proof strength. I'm not interested in pre-tension caused by tightening, as it is hand tightened, really just like to know how much load can be applied in direct tension. Any offers?