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 service brake system for a machine includes a brake assembly including a brake actuator and a brake spring. The brake actuator is movable in a brake application direction and in a brake disengagement direction. The brake spring is arranged to apply a spring force on the brake actuator in the brake application direction. The brake actuator has a first pressure chamber and a second pressure chamber. Pressurized fluid introduced into the first and second pressure chambers respectively applies a first and a second hydraulic force on the brake actuator in the brake disengagement direction counter to the spring force. A first pressurized fluid supply is in communication with the first pressure chamber for providing pressurized fluid to generate the first hydraulic force. A second pressurized fluid supply in communication with the second pressure chamber for providing pressurized fluid to generate the second hydraulic force.

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.