Influence of Back Rake Angle of a Threading Cutter on the Drill-String Tool-Joint Pitch Diameter

Analytical Model of Tapered Thread Made by Turning from Different Machinability Workpieces

“…At the same time, the segment AD i M 2 is parallel to the Z-axis, and its length, |D i M 2 |, determines the Z-coordinate of point D. The segment AM 2 is the projection of the cutting edge AD i on the X0Y plane. Point M 1 is the point of contact of the straight line M 1 M 2 with the initial cylinder with radius r 1 [61].…”

“…The effect of the rake angle on the thread accuracy during turning is explained in manuscripts [60,61]. There are few works containing the study of the influence of other tool geometric parameters on thread profile accuracy [22,62], but there are not any studies presenting the mutual influence of all main tool geometric parameters on the accuracy of thread.…”

“…This paper is based on the analysis of the accuracy of the kinematics of manufacturing convolute and involute worm screws, but it does not focus on the geometric parameters of the tools for their manufacture. In the study [79], the authors Onysko and Kopei used application shown in [80] to prove by calculations that the presence of a screw lead angle of λ = 2.24° for the NC10 tool-joint thread (the smallest size drill-string connect thread), and accordingly, the angle of inclination of the cutting edge of the cutter λz = 2.24°, causes a decrease in the half-profile angle α/2 by 0.24°, which is more than 30% of the tolerance. Description of the visual algorithm is presented Such an angle for tool joints is quite insignificant; it does not cause alarm among manufacturers regarding the influence on the accuracy of the thread profile, and therefore, the operating instructions for threaded cutters contain the method of using tools containing a plate installed at an angle relative to the axis of the thread.…”

“…In the study [79], the authors Onysko and Kopei used application shown in [80] to prove by calculations that the presence of a screw lead angle of λ = 2.24 • for the NC10 tool-joint thread (the smallest size drill-string connect thread), and accordingly, the angle of inclination of the cutting edge of the cutter λ z = 2.24 • , causes a decrease in the half-profile angle α/2 by 0.24 • , which is more than 30% of the tolerance. Description of the visual algorithm is presented on the pages 350-360 of work [80]. The methodology of the theoretical part of that research is essentially a continuation of the approaches presented in Figure 5 and described by Equation (17).…”

“…The right cutting edge AB i together with the left AD i form a flat rake surface of the B i AD i cutter, which is highlighted in grey. The B i AD i plane is inclined to the XZ plane at an angle λ [80].…”