Abstract: A leg assembly of a tricone bit includes a cone and a leg fitting inside the cone. The leg includes an axis defining an axial center of rotation of the cone, a first raceway for a first row of bearings, a second raceway for a second row of bearings, and a third raceway for a third row of bearings disposed between the cone and the leg, at a distal end, at a middle section, and at a proximal end of the leg. A first clearance for the first row of bearings for the first raceway is less than a second clearance for the second row of bearings for the second raceway, which is less than a third clearance for the third row of bearings for the third raceway, such that the first row of bearings initially supports most of the radial load applied to the tricone bit.

Abstract: Roller cone drill bits and methods of increasing the wear resistance of a roller cone drill bit are disclosed. The roller cone drill bit includes a plurality of rolling elements within a bearing assembly of a cone. Each rolling element of the plurality of rolling elements may have a surface hardness of HRC 59-63, a hardened depth that is 0.5 mm to 3.0 mm deep, and may be derived from a low carbon bearing steel material. The hardened depth is measured from the surface of each rolling element and the low carbon bearing steel material has, by weight percent, from 0.12% to 0.25% carbon.

Abstract: A grading machine includes a machine body, a grading blade supported by a circle, a drawbar connecting the grading blade and the circle to the machine body, and a circle drive system including a circle drive motor and a gear box. The gear box is configured to engage with and rotate the circle relative to the drawbar around a circle axis. The gear box includes a first gear that rotates about a first axis of rotation that is parallel to the circle axis, and the gear box also includes a second gear that rotates about a second axis that is parallel to the circle axis and spaced away from the first axis of rotation.

Abstract: A grading machine includes a machine body, a grading blade supported by a circle, a drawbar connecting the grading blade and the circle to the machine body, and a circle drive system including a circle drive motor and a gear box. The gear box is configured to engage with and rotate the circle relative to the drawbar around a circle axis. The gear box includes a first gear that rotates about a first axis of rotation that is parallel to the circle axis, and the gear box also includes a second gear that rotates about a second axis that is parallel to the circle axis and spaced away from the first axis of rotation.