Friction hold wear bushing

An apparatus to protect the upper section of a string of oil well casing from drill string members passing therethrough, comprising:

• a tubular mandrel having a lower section for positioning within the upper section of the casing;
• the mandrel having a bore therethrough sufficient for the passage of drill string members;
• pliable packing disposed around and retained with the lower section of the mandrel;
• the packing being dimensioned so as to be positioned within and to be squeezed against the casing bore;
• means for reversably compressing the packing between the mandrel and the casing bore such that the mandrel is sufficiently mounted with the casing, against forces caused by the drill string members;
• said means for reversably compressing the packing including external threads formed with an upper portion of the mandrel, and annular ring positioned around the mandrel below the packing, means to retain the ring against downward movement with respect to the mandrel, a nut formed with internal threads for cooperating with the mandrel threads so as to compress the packing between the ring and the nut when the nut is rotated, such that the packing is deformed laterally and forced into contact with the mandrel and the casing bore so as to firmly mount the mandrel with the casing;
• the nut having an upper bore formed with a plurality of inwardly projecting circumferential flanges, each flange being axially disposed from the others, each of the flanges extending for substantially one half the circumference around the bore, axially adjacent flanges being positioned diametrically opposite from each other;
• and a wrench member having sufficient length to reach and engage the nut when the nut and mandrel are mounted with the casing, the wrench and nut comprising a releasable connection sufficient to rotate the nut to thereby reversably compress the packing, and to lift the apparatus.