Hammertool with a reciprocating piston member (35) slideably positioned in a barrel (27) and moving between a forward limit position and a rearward limit position. An air passageway (31) open to air is formed in the barrel (27) and a first passageway (43) and a second passageway (41) are formed in the piston member (35). In the operational mode, a ram (54) and the barrel (27) coact to alternately seal and expose an enclosure (73) to the outside air through the first passageway (43) and air passageway (31) whereby the ram (54) is urged axially toward or away from the tool bit through the pressure differentials established thereby in the enclosure (73). The second passageway (41) is formed in a forward portion (39) and is spaced a predetermined distance away from the first passageway (43) such that the second passageway (41) communicates with the air passageway (31) to ensure that air is supplied to the enclosure (73) during the course of the movement of the piston member (35) from said forward limit position to said rearward limit position when the hammer tool is operating in the idle mode. In this way, the ram (54) remains inactive when the tool bit is removed or when the tool is lifted from the work surface because no significant pressure differentials are developed in the enclosure (73).
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