METHOD FOR CUTTING PRECISE INTERNAL THREADS Russian patent published in 2003 - IPC

FIELD: metal cutting, namely cutting metric thread or buttress thread in number program control machine tools. SUBSTANCE: method comprises steps of using combination type cutting process by means of round multithread chaser; in order to provide desired accuracy and high efficiency, at first working pass cutting maximally admissible by strength of cutter part of profile height; at next working passes (after first finishing pass) providing combination type cutting when blades of cutting portion of chaser work according to profiling mode for forming lateral sides of profile. Two last cutting teeth form recess of thread turn; the last tooth is calibrating one and it performs trimming of thread profile. Length of near-apex cutting edge of chaser tooth is determined according to formula given in description of invention. EFFECT: enhanced accuracy and efficiency of method. 2 dwg