The boring machine has a housing (2) containing a rotary mechanism (7) driving a reciprocating hammer (8). The hammer strikes a boring tool (3) which is of hexagonal (4) cross-section. There is a pivoting mechanism (14) which enables the boring tool to swing through an arc to enable it to chip away at a wide area of the end of the tunnel. The tool may be hollow and water may be pumped though it to lubricate the working tip and reduce the production of dust.
