A composite drill bit has one or more scraping-wheel cutting units disposed on fixed-blade. The drill bit comprises a bit body, fixed-blades, and scraping-wheels. The angular deflection of the scraping-wheel is in the range of 20||90. The scraping-wheel cutting unit has a scraping-wheel shaft and a scraping-wheel with cutters disposed thereon. The scraping-wheel cutting unit is disposed on the fixed-blade by a rotary connection.

A composite drill bit has one or more scraping-wheel cutting units disposed on fixed-blade. The drill bit comprises a bit body, fixed-blades, and scraping-wheels. The angular deflection of the scraping-wheel is in the range of 20||90. The scraping-wheel cutting unit has a scraping-wheel shaft and a scraping-wheel with cutters disposed thereon. The scraping-wheel cutting unit is disposed on the fixed-blade by a rotary connection.

An earth boring bit has rotary cutters with embedded tungsten carbide inserts and milled steel teeth. The teeth and the grooves are first milled into the cutters, with the grooves extending between bases of the teeth, parallel to the crests of the teeth. Hard facing is applied to surfaces of the teeth and the grooves, and then the cutters are heat treated. Insert sockets are drilled into the teeth, centrally disposed in crests of the teeth. The tungsten carbide inserts are secured in the insert sockets, aligned for forming cutting profiles with respective ones of the milled teeth. The cutters are preferably frustoconically shaped and used for a rotary cone rock bit, and the tungsten carbide inserts configured as chisel-shaped inserts having crests which are aligned parallel to the crests of the milled steel teeth.

An earth boring bit has rotary cutters with embedded tungsten carbide inserts and milled steel teeth. The teeth and the grooves are first milled into the cutters, with the grooves extending between bases of the teeth, parallel to the crests of the teeth. Hard facing is applied to surfaces of the teeth and the grooves, and then the cutters are heat treated. Insert sockets are drilled into the teeth, centrally disposed in crests of the teeth. The tungsten carbide inserts are secured in the insert sockets, aligned for forming cutting profiles with respective ones of the milled teeth. The cutters are preferably frustoconically shaped and used for a rotary cone rock bit, and the tungsten carbide inserts configured as chisel-shaped inserts having crests which are aligned parallel to the crests of the milled steel teeth.

A drill bit for forming a wellbore through a geologic formation includes a connector configured for connection to a drill string and a bit body coupled to the connector. A fixed cutting element is mounted on the bit body for rotation with the bit body and a slot extends through the bit body. A rolling cutting blade is supported in the slot such that an exposed segment of the cutting blade protrudes from slot and concealed segments of the rolling cutting blade adjacent the exposed segment are disposed within the slot. The rolling cutting blade rotates to thereby conceal the exposed segment and expose the concealed segments. A plurality of rotating cutting elements are supported on a periphery of the rolling cutting blade.

A drill bit for forming a wellbore through a geologic formation includes a connector configured for connection to a drill string and a bit body coupled to the connector. A fixed cutting element is mounted on the bit body for rotation with the bit body and a slot extends through the bit body. A rolling cutting blade is supported in the slot such that an exposed segment of the cutting blade protrudes from slot and concealed segments of the rolling cutting blade adjacent the exposed segment are disposed within the slot. The rolling cutting blade rotates to thereby conceal the exposed segment and expose the concealed segments. A plurality of rotating cutting elements are supported on a periphery of the rolling cutting blade.

A cutting element may include a substrate including a plurality of metal carbide particles and a first metal binder having a first metal binder content; an outer layer of polycrystalline diamond material at an end of the cutting element, the polycrystalline diamond material including a plurality of interconnected diamond particles; and a plurality of interstitial regions disposed among the interconnected diamond particles, the plurality of interstitial regions containing a second metal binder having a second metal binder content. The cutting element also includes at least one transition zone between the substrate and the outer layer, the at least one transition zone including a plurality of refractory metal carbide particles and a third metal binder having a third metal binder content, the third metal binder content being less than the first metal binder content and the second metal binder content.

A cutting element may include a substrate including a plurality of metal carbide particles and a first metal binder having a first metal binder content; an outer layer of polycrystalline diamond material at an end of the cutting element, the polycrystalline diamond material including a plurality of interconnected diamond particles; and a plurality of interstitial regions disposed among the interconnected diamond particles, the plurality of interstitial regions containing a second metal binder having a second metal binder content. The cutting element also includes at least one transition zone between the substrate and the outer layer, the at least one transition zone including a plurality of refractory metal carbide particles and a third metal binder having a third metal binder content, the third metal binder content being less than the first metal binder content and the second metal binder content.

A cutting element for a drill bit includes an outer support element and an inner rotatable cutting element, a portion of which is disposed in the outer support element, where the inner rotatable cutting element has a body with a non-planar cutting face.

A cutting element for a drill bit includes an outer support element and an inner rotatable cutting element, a portion of which is disposed in the outer support element, where the inner rotatable cutting element has a body with a non-planar cutting face.