Abstract: A split head hammer including a head (4) from one end of which a replaceable hammer shaft (2) projects, comprising two head parts (4A, 4B) which can be connected to grip a pair of striking pieces (11) and the shaft (2), the shaft being sunk fully within the head. The head grips the shaft at a plurality of circumferentially-shaped positions (70). Striking pieces suitable also for use in other designs of hammer e.g. solid head and having a rearward extension (46) of smaller section than the open end (21) of the socket can be retained in the socket by plastic flow and/or by a separate retainer, preferably an annular metal washer (50, 60) usefully toroidal (60). Not only the striking pieces (11) but also the shaft (2) can be simply replaced by the user, notwithstanding that the hammer is suited to heavy-duty use.