Improvements relating to reamers

A movable cutting tool for scraping or cutting a surface of a hole in the ground is disclosed. The tool comprises a first frame (2) having a generally longitudinal axis and adapted to be suspended from a hoist or trailed from tackle so as to be capable of moving the frame in a direction more or less parallel with the axis of the hole; at least one cutting or scraping element (1) supported on the exterior surface of said first frame (2); a second frame (9) adjacent said first frame (2) and adapted to slide against a surface of the hole opposite said surface to be modified, and adapted to be suspended or trailed independently of said first frame; a linkage (11, 12, 13) between said first frame (2) and said second frame (9) such as to cause the second frame (9) to move towards or away from the first frame (2) when hoisted or lowered or trailed relative to the first frame; and means (14) for limiting and/or controlling the extent of relative movement between said first and second frames in order to regulate the depth of penetration of the cutting or scraping element(s) (1) into the surface when contact of said element(s) with said surface is caused by increasing the mutual separation between said first and second frames.