REVERSIBLE SCREWING TAP Russian patent published in 2008 - IPC B23G5/06 

FIELD: technological processes.

SUBSTANCE: screwing tap is designed for cutting threads and has teeth with lead-in and calibrating parts, chip flow grooves and a shank end. The teeth are edged on the profile of the threads on the front surface and have a rear end. To enable cutting on both sides and increasing durability, the teeth are made with extra lead-in parts on the side of the shank end symmetrically on the width relative the radial axis. The teeth have the same profile on both sides and are adjacent to short threaded spines, passing into a plane on the rear surface and forming back angles. The screwing tap can have a second shank end on the other side. The chip flow grooves can have a symmetrical profile, for example, on a segment of a circle.

EFFECT: possibility of cutting threads either sides.

3 cl, 4 dwg