Abstract: A slip ring assembly including a slip ring and an electrical contact assembly. The slip ring defines a circumference and an electrical contact groove extending around the circumference of the slip ring. The electrical contact assembly preferably includes a plurality of electrical contacts spaced around the circumference of the slip ring for engaging the electrical contact groove. In addition, an urging mechanism is preferably associated with each of the electrical contacts for urging the electrical contacts toward engagement with the electrical contact groove. Finally, a wiper is preferably associated with each of the electrical contacts for extending within the electrical contact groove to inhibit a fluid from passing through the electrical contact groove.

Abstract: A variable gauge drilling apparatus and a method for assembling a variable gauge drilling apparatus for insertion in a subject borehole. The variable gauge drilling apparatus includes: an apparatus housing having a housing size which is suitable for insertion in a subject borehole which has a subject borehole size within a design range of borehole sizes; a plurality of interchangeable borehole engaging devices having different device sizes for mounting on the apparatus housing to provide the drilling apparatus with a drilling apparatus size within a range of drilling apparatus sizes, wherein the range of drilling apparatus sizes is compatible for use of the drilling apparatus within the design range of borehole sizes; and a universal borehole engaging device mount located on the apparatus housing, wherein the mount is configured to accept for mounting any one of the plurality of interchangeable borehole engaging devices.