A reciprocable impact hammer

In the field of borehole creation there is a need for a reciprocable impact hammer with a tool that is rotatable while under load. A reciprocable impact hammer ( 10 ) for use in a downhole location comprises a tool support member ( 11 ); a hammer member ( 12 ); a jack mechanism ( 13 ); a connector member ( 14 ); and a transmission ( 16 ). The transmission ( 16 ) converts linear motion of the connector member ( 14 ) to rotary motion of the hammer member ( 12 ) whereby when a force acts on the connector member ( 14 ) via the hammer member ( 12 ) and the tool support member ( 11 ) operation of the jack mechanism ( 13 ) causes initial elongation of the impact hammer ( 10 ) followed in succession by: (i) collapsing of the hammer member ( 12 ) and the tool support member ( 11 ) together such that the hammer member ( 12 ) separates from the connector member ( 14 ) and imparts an impulse to the tool support member ( 11 ); and (ii) movement of the connector member ( 14 ) towards the hammer member ( 12 ) under the influence of the force whereby the transmission ( 16 ) causes rotation of the remainder of the impact hammer ( 10 ).