Abstract: A downhole tool including a selectively releasable joint, a downhole drilling assembly including the downhole tool, and a corresponding method. In one embodiment of the invention, a downhole drilling assembly includes a downhole tool having a first body and a second body mounted for relative rotation; a joint part for use in forming a selectively releasable joint between the second body and a part of the assembly coupled to the second body; and one or more locking member(s) for locking the first and second bodies relative to one another against relative rotation so as to allow a release force to be applied through the first body to release the releasable joint and allow the tool to be separated from the part of the assembly.

Abstract: The gas cylinder lift is a hydraulic jack mounted on a frame and secured to a mobile cart. The jack lifts a support post, which is guided by a slot running vertically up a guide post. A bucket connected to the bottom of the support post is adapted to hold heavy welding machine gas cylinders or other similar containers. A safety chain or line secured at the top of the support post, and another safety line in the form of an elastic cable or bungee cord, along the bucket help stabilize the cylinders during transport. A safety bolt locks the support post to the guide post during transport to prevent the support post and bucket from moving. Other items, such as welding accessories, may be transported on the cart platform.

Abstract: An earth boring tool includes two coaxially-aligned, positive displacement motors. One motor turns a pilot bit and the other turns a reamer concentric with the pilot bit. The central bit bores the center of the hole and the reamer enlarges it. The central bit is rotated relatively faster, while rotation of the larger diameter reamer is relatively slow. The tool can thus be used to bore larger diameter holes without slowing drilling rates or adversely affecting performance of the cutter elements due to higher tangential velocities.

Abstract: The invention relates to a downhole tool including a selectively releasable joint, a downhole drilling assembly including the downhole tool, and to a corresponding method. In one embodiment of the invention, a downhole drilling assembly includes a downhole tool having a first body and a second body mounted for relative rotation; a joint part for use in forming a selectively releasable joint between the second body and a part of the assembly coupled to the second body; and one or more locking member(s) for locking the first and second bodies relative to one another against relative rotation so as to allow a release force to be applied through the first body to release the releasable joint and allow the tool to be separated from the part of the assembly.

Abstract: A stabilization device for a down-hole motor for use in drilling operations for example in oil-fields to control any tendency for spiralling of the tool bit during the drilling action and to permit steering by a "orientate and rotate" technique. In an example of the device, an end portion of a motor shaft (26) projects from a motor body (20), the projecting portion being comprised of an attachment apparatus or bit box (28) by which a tool bit (38) is connected for rotation. The bit box (28) may be separable from the shaft (26) or may be integrally formed therewith, but, is provided with a stabiliser means (32) in the form of part-helical vanes surrounding the bit box (28). The bit (38), when secured in the box (28), is located immediately adjacent the stabilising vanes (32) for maximum control; additionally, stabiliser vanes (22,24) may be provided on the motor body portion (20) and, if required, on the selected tool bit.