A roller cone drill bit includes a pressure equalization bore defined within the roller cone drill bit that includes a lubricant chamber portion and an open portion. The drill bit also includes a lubricant passage defined within the drill bit and fluidically coupled to a first end of the lubricant chamber portion. Additionally, the roller cone drill bit includes a floating plug positioned within the pressure equalization bore between the lubricant chamber portion and the open portion. The floating plug is slidable along the pressure equalization bore and configured to seal the lubricant chamber portion from the open portion. Moreover, the roller cone drill bit includes a stop positioned at least partially within the pressure equalization bore or the lubricant passage to restrain the floating plug from sliding into the lubricant passage through the first end of the lubricant chamber portion.

A rotary drill tool for cutting rock includes a set of journal legs that rotatably mount rotating cone shaped cutters via respective bearing assemblies. A fluid supply passageway extends through the journal legs to provide a cooling and cleaning fluid to the bearings during use. A by-pass passageway extends through a base region of the spindle that mounts each cone cutter and is provided in direct fluid communication with the supply passageway to divert the fluid to a base region of the bearing assembly.

A rotary drill tool for cutting rock includes a set of journal legs that rotatably mount rotating cone shaped cutters via respective bearing assemblies. A fluid supply passageway extends through the journal legs to provide a cooling and cleaning fluid to the bearings during use. A by-pass passageway extends through a base region of the spindle that mounts each cone cutter and is provided in direct fluid communication with the supply passageway to divert the fluid to a base region of the bearing assembly.

A disclosed example embodiment includes a drill bit used to form wellbores in subterranean formations. The drill bit includes a drill bit body for coupling to a lower end of a drill string. The drill bit body includes at least one support arm having an inwardly extending journal with a journal bearing having at least one radially reduced pocket extending at least partially circumferentially around the journal bearing including a load side of the journal bearing. At least one rotary cutter assembly is rotatably mounted to the journal. A plurality of cutting elements is disposed on the at least one rotary cutter assembly. At least two independent hardmetal pads are positioned within the at least one radially reduced pocket such that the hardmetal pads have a gap disposed therebetween.

A rotary drill tool for cutting rock includes at least one journal leg mounting a spindle and a respective rotary cone cutter. The spindle includes a plurality of fluid distribution passageways arranged to provide a supply of a cooling and cleaning fluid to the bearing assembly. Vent holes are provided through the cutter to allow an exhaust flow of fluid and an annular seal is provided at a base region of the spindle to maintain a positive fluid pressure within the cutter cavity to prevent dust and dirt ingress.

A rotary drill tool for cutting rock includes at least one journal leg mounting a spindle and a respective rotary cone cutter. The spindle includes a plurality of fluid distribution passageways arranged to provide a supply of a cooling and cleaning fluid to the bearing assembly. Vent holes are provided through the cutter to allow an exhaust flow of fluid and an annular seal is provided at a base region of the spindle to maintain a positive fluid pressure within the cutter cavity to prevent dust and dirt ingress.

A shank adapter, rock drilling machine and method of mounting a shank adapter of a rock drilling machine inside a slide bearing element. The shank adapter includes a coupling head and a rotation portion at its opposite ends, and a flushing portion located therebetween. Outer diameters of the coupling head and the rotation portion are both greater than outer diameters of portions of the shank adaptor located therebetween.

A shank adapter, rock drilling machine and method of mounting a shank adapter of a rock drilling machine inside a slide bearing element. The shank adapter includes a coupling head and a rotation portion at its opposite ends, and a flushing portion located therebetween. Outer diameters of the coupling head and the rotation portion are both greater than outer diameters of portions of the shank adaptor located therebetween.

A rock bit for blast hole drilling includes: a bit body having a coupling formed at an upper end thereof, a plurality of lower legs, a dome formed between the legs, and a bore formed through the coupling and the dome; a plurality of skirts, each skirt covering a gap formed between adjacent legs and each skirt mounted to edges of adjacent legs; a plurality of roller cones, each rotary cone rotatably mounted to a respective bearing shaft of a respective leg; a row of gage cutters mounted to each roller cone; a row of inner cutters mounted to each roller cone; one or more nose cutters mounted to each roller cone; and a center jet secured in the bore. Each cutter is an insert.

A rock bit for blast hole drilling includes: a bit body having a coupling formed at an upper end thereof, a plurality of lower legs, a dome formed between the legs, and a bore formed through the coupling and the dome; a plurality of skirts, each skirt covering a gap formed between adjacent legs and each skirt mounted to edges of adjacent legs; a plurality of roller cones, each rotary cone rotatably mounted to a respective bearing shaft of a respective leg; a row of gage cutters mounted to each roller cone; a row of inner cutters mounted to each roller cone; one or more nose cutters mounted to each roller cone; and a center jet secured in the bore. Each cutter is an insert.