A device for a coulter (1) comprising a disc (12) and a share (13) provided with a share front (131) facing in the working direction of the coulter (1), wherein the share (13) is provided with a vertical opening (132) having a front portion (133) provided with two opposite side surfaces (133) converging in the direction of the share front (131), and being arranged for receiving a complementary portion (114b) of a share fastener (114)； wherein the share (13) and the share fastener (114) each is provided with a support portion (135 and 114f, respectively) arranged in a manner allowing it to bear against a seat (114d and 134a, respectively) disposed on the share fastener (114) and the share (13), respectively, the share (13) bearing in a supporting manner against the share fastener portion (114b)； and wherein the opening (132) of the share (13) is arranged in a manner allowing it to receive a locking device (14) which, upon bearing against a rear portion (14c) of the share fastener (114), bears in a supporting manner against a rear portion (136) of the opening (132).
