An asymmetric gage row insert provides a larger amount of wall contacting surface thereby decreasing the wear on the gage insert and increasing the ability of the earth boring apparatus to maintain a full gage hole. The insert has a shape prior to assembly onto the earth boring apparatus that includes a base integrally joined to an asymmetric head. The base is mounted in a socket in the earth boring apparatus. The head projects from the earth boring apparatus and includes an extended gage cutting surface. The gage cutting surface is the largest plane surface on the head. The gage cutting surface contacts the wall of the hole with the majority of the length of its extended surface and with the same angle as the gage angle of the bit.
A rolling cone drill bit is provided that has gage inserts on the first row from the bit axis to cut to full gage diameter that have a cutting portion enhanced with a layer of super abrasive material. The gage cutting surface has a center axis that is canted to be more normal to the gave curve such that its point of contact at gage is away from the thinner portion of the layer of super abrasive material.
Inserted hard metal cutting elements are disclosed which are advantageous for inserting into the cutters of drilling bits used in drilling underground formations. The inserted cutting elements comprise asymmetrical inserts placed in at least one row of a cutter in alternating alignment circumferentially therearound.
A rolling cone drill bit is provided that has gage inserts on the first row from the bit axis to cut to full gage diameter that have a cutting portion enhanced with a layer of super abrasive material. The gage cutting surface has a center axis that is canted to be more normal to the gage curve such that its point of contact at gage is away from the thinner portion of the layer of super abrasive material.
A protruding insert for use in an oil well drill bit is disclosed which insert is made of a hard metal substance and utilizes a tangential spherical surface having opposed flattened sides.
A percussion drill bit for drilling a bore includes a drill body having a connecting section at a rear end thereof for connection to a percussive unit, and a plurality of cemented carbide buttons embedded in a front end of the drill body. Each button comprises a cemented carbide body having a rear mounting portion embedded in the drill body, and a front end protruding from the drill body. The front end of the cemented carbide button is substantially semi-spherically curved and defined by a radius whose origin is disposed axially rearwardly of a plane through the largest diameter of the button. The button projects from the drill bit body a distance which is not less than 50% of the button diameter. A conical intermediate surface forms, in cross-section, an acute angle of about 13 19.degree. with an envelope surface of the rear mounting portion.
