METHOD OF DEEP HOLE MACHINING IN TUBULAR BILLET Russian patent published in 2019 - IPC B23B35/00 

FIELD: machine building.

SUBSTANCE: invention relates to machine building and can be used in processing of deep holes in tube workpieces with application of metal cutting machines and milling cutter for vortex milling. Treatment is carried out with a device comprising a boring bar with a cutting tool consisting of two disk modular cutters with a width of the cylindrical part of the cutting edge of the second cutter, equal to difference between pitch of cut thread and width of cylindrical part of cutting edge of first cutter installed at distance from each other, corresponding to 1.3–1.7 times pitch of thread to be cut, at an angle of not more than 2° to the axis of the machined hole, located on the eccentric bearings in the pinions with cutting and mandrel teeth and performing translational and rotary motion. During the straight working stroke, the recesses are cut with the front cutter and the coil is cut off with the next cutter and boring, pulling and mandreling of the deep hole are combined, and during the reverse stroke the reworking of the treated deep hole is performed.

EFFECT: raised efficiency of machining of holes of pipe lengthy billets.

1 cl, 2 dwg