Elastic Comparison of Four Thread Forms.

Abstract : Previously, this author introduced the concept that all screw thread forms have a structural Characteristic Curve, which defines the basic stress concentration as a function of a radial stress in the joint. An additional set of characteristic curves is produced when the general stress field is considered. The standard analysis is for a single thread tooth, isolated from a long chain of identical teeth, that is computationally efficient and facilitates the calculation of a family of characteristic curves. This work presents the characteristic plots for four different threads, the 7 degree British buttress, a 15 degree asymmetric V, the 20 degree Benet buttress, and a special 30 degree V. These four threads were selected because they are or may be useful in high pressure systems. Together they suggest the possibility of a standard thread family for high pressure applications.