body 12 and a coaxial tailpiece 40 an air driven piston like striker 70 reciprocates lengthwise in the housing 14 if the striker 70 impacts at the right end of the housing 14 as seen in fig1 the tool will be driven forward conversely if the striker impacts at the left end of the housing as seen in fig3 reverse motion results to control the motion of striker 70 a directional valving member 100 is provided which is slidably mounted on inner fluid inlet tube 60 and outer fluid inlet tube 58 the valving member 100 is slidable between a first forward position on the tubes as seen in fig1 and a second rearward position as seen in fig3 a valving member chamber 102 is defined inside the valve member 100 a spring 104 inside valving member chamber 102 is in contact with the forward end of the valving member 100 and with outer fluid inlet tube 58 adjacent the rear end of the valving member 100 a slotted spring supporting ferrule 68 circumferentially surrounds the inner fluid inlet tube and comprises three slots which communicate the valve member chamber with the fluid supply the striker 70 defines jointly with the housing 14 a rear operating chamber 72 and a forward operating chamber 80 the striker 70 is essentially cylindrical in shape but has a frustroconical taper at the front to form a flat forward impact surface 71 the striker has ports 74 through the cylindrical shell of the striker which connect the forward chamber 80 alternately with the rear chamber 72 and then with the exhaust passages 49 during reciprocal movement there is an anvil 90 fixedly attached to the outer housing 14 which is circumferentially surrounded by the outer housing 14 at the.