METHOD OF CUTTING THREADS AT THE END OF CASING PIPES AND COUPLINGS Russian patent published in 2018 - IPC B23G1/00 

FIELD: manufacturing technology.

SUBSTANCE: method involves sequentially turning of workpieces on a CNC lathe with a rough-edged comb with a front angle of 10–15°, the teeth of which are made with reinforcing bevels and rounded cutting edges with a multilayered MT CVD coating, and a finishing shaped cutter, while a rough stock is removed in 1, 2 or 3 junctions with cooling at a cutting speed that provides chip shredding, finishing stock is removed for 3–7 transitions with a cutting depth of 0.03–0.07 mm, the latter of which is performed without cooling at a reduced speed of spindle rotation and the axial displacement of said shaped tool by 0.03–0.09 mm to the side opposite feed-motion. Shaped cutter made with a horizontally located front surface with a multilayered PVD coating is used. Comb and the cutter are mounted on a lathe with a threaded microscope, in the eyepiece of which the thread profile is visible. In this case, the head of the microscope is exposed on one of the generatrices of the processed outer conical surface of the cantilevered workpiece.

EFFECT: increased accuracy of the threads at the ends of the pipes and couplings is achieved and the spontaneous unscrewing of the threaded joint is prevented.

1 cl, 3 dwg