Abstract: The disclosed invention provides a system and method for assisting a purchasing user in selecting a good or service from among a host of goods or services offered on a computer network-based purchasing system. The invention comprises a commerce promotion facility, which in turn comprises a server computer and a user computer at the purchasing location, connected to each other via a wide area network. The facility features the ability to assist the purchaser with making a product selection by asking the user a series of dynamic questions. The system is able to use the answers to the questions to limit the possible products offered to the user, greatly enhancing usability of the system. An embodiment particularly for the selection and/or purchase of drilling bits and oilfield services and equipment is disclosed.

Abstract: A rock bit has a body and three cutters that include generally conical surfaces, at least one of which contains an outermost, circumferential row of heel teeth that dislodge cuttings from the borehole wall and bottom. The heel teeth form a corner with the borehole wall with successive contact points defined by the path of outer edges of the heel teeth while rotating into, and prescribing, the corner as it spirals downwardly during drilling. The rotational axis of the cutter is offset from the geometric centerline or intended rotational axis of the bit. Stabilizing pads extend outwardly from the body, each concluding in a surface that contains a low-friction, wear-resistant surface that engage the wall of the borehole. The center of each surface is located directly across from the contact point of an opposed cutter.