TAP FOR DEAD HOLES Russian patent published in 2011 - IPC B23G5/06 

FIELD: process engineering.

SUBSTANCE: proposed tap comprises stem, gage part and cutting part representing an intake cone. Said cutting part has two perpendicular slit-like cutouts made on tap face side that feature depth equal to 0.3-0.6 of cutting part length. Cylindrical support section is made on intake cone side that has chip flutes with length equal to 0.1-0.2 of intake cone length and diametre equal to the least diametre of intake cone. Note here that cutting part length equals total length of support part and intake cone. Aforesaid cutouts feature width equals 0.6-1.0 mm with its minor magnitude corresponding to small-diametre taps.

EFFECT: expanded performances, higher hardness and quality of thread.

2 dwg