MILLING TOOL FOR CUTTING THE OPENING IN WELL CASING STRING Russian patent published in 2017 - IPC E21B29/06 

FIELD: mining.

SUBSTANCE: device includes starting, advance and calibrating mill reamers with cutting plates fixed in them. The cutting and pass-through rovers-ravers are made in the form of a single hollow body, the calibrating router-rake is made in the form of a hollow shaft. The single body and the hollow shaft are rigidly connected to each other. Cutting plates fixed in starting mill reamer are located concentrically relative to central longitudinal axis of single shaft. Calibrating router-rake is made with screw channels forming helical blades with fixed cutting elements in them. A single body of cut-in and pass-through rovers-ravers is made with screw channels for a passive router-raiser, forming screw blades with fixed cutting inserts. The device contains on the periphery of a single hollow body, in the place of formation of a rifled router-raiser, side faces, and between them - radially outwardly projecting protrusions. Each side face has a base surface in a plane along the central longitudinal axis of the single hollow body and each radially outwardly projecting projection on the insertion side of the cutting inserts has a base surface in a plane disposed transversely to the base face of the side face and also comprises a single hollow shell, in the place of formation of the rifled milling cutter-raiser, frontal faces, between them - end projections, and in the central part of the single hollow body contains the end cavity. Each radially outwardly extending stop on the insertion side of the cutting inserts has a base surface in a plane disposed transverse to the base face of the longitudinal face, each end face having a base surface in a plane along the generatrix of the front surface of the helical blade and each end stop on the insertion side base surface in a plane located across the base surface of the end face. Cutting plates are fixed by hardfacing of carbide crumbs with lateral and frontal facets, radially outward protrusions, end protrusions and end cavity, as well as with longitudinal and end faces radially outwardly directed by the stops and end stops forming the pass-through router-rake.

EFFECT: resource is increased, cyclic shock loads are reduced, chipped and dying of the cutting inserts are prevented.

6 cl, 9 dwg