The Split Nut: An Easy to Fit Nut with a Higher Inherent Strength

Abstract

The split nut, invented by Commander P. Y. Williams, is easier to fit than the conventional nut and has a higher inherent strength. The two halves of the nut, which is coned at both ends, fit into a conical washer that forces them tightly onto the bolt. The positive clamping action increases the radial load on the threads, which reduces the tensile bending stress at the root of the thread. The load distribution in the threads is also improved, because the change in thread pitch caused by the axial deformation of the nut and bolt is partly compensated by a rotation of the nut halves about an axis normal to that of the bolt. These two effects reduce the maximum tensile stress at the root of the thread to about half of that in the conventional nut.