METHOD OF FEMALE THREAD MAKING Russian patent published in 2014 - IPC B23G5/06 B21H3/08 

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming and cutting. Proposed process is implemented with the help of tap provided with thread cutting elements with exposed contour and chip removal sections. Tap thread ID at taper lead section is smaller than thread cutting ID by twice the depth of defect surface layer formed at cut thread turn top. Chip removal sections are equipped with cutter bits arranged at the last turn of taper lead and first gaging turn to cut flat profile of cut thread. This tap has lengthwise central bore and crosswise bores for forced feed of lubricant-coolant to cutter face surface cutting zone. Tape drive incorporates overrunning coupling with splines inclined to lengthwise axis. Said coupling is fitted in the bush splined bore. It can slide on guide keys arranged in drive case to increase spring rpm by pulse lengthwise force and compression spring.

EFFECT: higher precision and quality.

10 dwg, 1 tbl, 1 ex