Abstract: A cutting tool or pick on a rotary excavating head has a substantially flat body with leading and trailing flanks, one of these flanks having an arcuate recess or projection matingly engaged by a complementarily curved formation on an adjacent wall of a pocket of a tool holder defining therewith a rotary joint about which the body of the pick is swingable upon insertion of its shank into the pocket. A screw clamp inside the pocket wedges the pick firmly in a position which in one embodiment is adjustable by the provision of a toothed and an indented surface of the rotary joint enabling selective interfitting. The pick may be further braced by one or more additional screws threaded into it and bearing upon other pocket walls.