Geometric Modeling of Lathe Cutters for Turning High-Precision Stainless Steel Tapered Threads

The profiling of high-precision tool-joint tapered threads is performed according to an algorithm based on a convoluted screw model, which is functionally dependent on the cutter’s geometric parameters and the size of the thread itself. It is proved based on visualization of algorithm that effective production of exact tapered thread from stainless steel is possible only using cutters with a specially calculated profile based on interpolation of a hyperbolic curve. There is created an acceptable geometric model for the cutting part of the thread cutter, the profile of which is a function of the back rake angle. Based on the visualization, it is confirmed that the axial profile of the sides of the tool-joint thread made by the cutter with a non-zero back rake angle is actually curved. On the example of algorithmic calculation of shaping by turning the tool-joint tapered thread size 2 7/8 Reg, it is determined that the use of the cutter model with a back rake angle of 12° and with a usual profile of the cutting edge causes the exceeding of the nominal thread profile side half profile angle by 3–10%, which gives grounds for the use of cutters without correction of their edge profile.