Abstract: The present invention is for a drill string stabiliser tool (18) used in borehole drilling. The tool includes a symmetrical body (20) with a plurality of external recesses (22). The recesses (22) have internal opposite surfaces (23) which converge inwardly from the outer surface of the body. A pad assembly (24) is disposed in each recess (22) and includes a wedge block (28) with converging radially inwardly opposite side surface (29) complementarily abutting said recess surfaces. Each wedge block (28) has a bolt (30) securing said wedge block (28) to said body (20) and is slightly larger dimensioned than the recess (22). The angles of the wedge blocks and the recesses are so chosen to effect an interference fit so that when the wedge block (28) is forced into the recess (22) by use of the bolt (30) it is held there by an interference fit.