the head there projects a peripheral flange or skirt 16 buttress portions 18 are integrally formed between the skirt and the adjoining lateral faces of the head the laterally opposite sides of the skirt 16 project from both the shank and the head but the maximum front to rear dimension of the root of the head is substantially the same as the corresponding dimension of the skirt the skirt has a tapered thickness both the inner faces 20 and the outer faces 22 of its lateral regions include laterally opposite surfaces 20a 20b and 22a 22b which are inclined relative to one another to define an imaginary line of intersection l lying in the central plane of symmetry p of the pick containing the longitudinal axis of the pick thus the pick tends to be centered in the lateral direction the preferred included angle of the inner faces 20 is in the range 120 u00b0 175 u00b0 preferably 160 u00b0 175 u00b0 the oppositely inclined outer surfaces 22 may include a similar angle a step at the front of the skirt 16 forms an outwardly offset portion 24 relative to the lateral regions of the skirt the pick box 26 has a socket 27 opening onto an outer wall comprising laterally opposite surfaces 28 inclined at complementary angles to the inner lateral surfaces 20 of the pick skirt i e having an included angle which is substantially complementary to the angle subtended by the pick inner faces 20 these surfaces are separated by a groove 30 which is bisected by the center plane p and which runs the.