Abstract: A rigid drilling stabilizer having outwardly extending ribs is slidably received over a tubular member. A plurality of tapered slip segments are located around the tubular member and within and near each end of the rigid main body of the stabilizer. An end cap is threadedly engagable within each end of the rigid main body. Each slip segment has an inwardly projecting rib and adjacent recess which conform to the corresponding annular recess and rib on the end caps. As an end cap is threadedly engaged to the rigid main body of the stabilizer, the tapered slip segments are urged axially inwardly against a conforming tapered surface within the rigid main body. The slip segments are wedged against the rigid main body and against the tubular member thereby locking the stabilizer to the tubular member.

Abstract: A rigid stabilizer sleeve having outwardly extending ribs is slideably received over a drill collar. A pair of internal clamping rings are slideably received through each end of the rigid main sleeve. As a threaded end cap is threaded into the rigid main sleeve, the end clamp forces one ring of the pair against the other thereby producing a clamping effect whereby the stabilizer can be clamped at any desired position on the drill collar. An outer ring of the pair of rings has a groove and a rib disposed on its interior cylindrical surface; the portion of the end clamp received by the outer ring has a rib and a groove disposed upon its outer cylindrical surface.