Described herein is a bit (9) for excavation and compaction equipment (1) for erecting piles, the bit (9) being provided with a central body (21), an excavation screw (24) fixed to the central body (21), and a dislocating element (40) for compaction of the walls of the excavation, a retention device (25) that can be selectively re-closed being associated to the central body (21) for preventing fall of debris beyond a leading edge (27) of the screw (24) during extraction of the bit (9), and the dislocating element (40) being mounted on a fixed portion (28) of the retention device (25), and presenting a radial development, which decreases with respect to a rotation of excavation of the excavation screw (24) for compaction of the walls (3a) of the excavation (3) during extraction of the bit (9).