through vents not shown in the casing and into an exhaust passage 60 formed in the housing 12 these vents are conventional in construction and arrangement and will not be further described herein the exhaust passage 60 extends to an exhaust exit 62 at the same end of the tool 10 where the inlet connection 14 is located in addition exhaust air can be passed through whichever of the forward and reverse passages 46 48 which is not being used to deliver high pressure air to the motor 50 through the valve assembly 22 to the exhaust passage 60 as will be described hereinafter the bushing 40 of the valve assembly 22 is tubular in shape is formed with a rectangular recessed flat 64 on an inlet side of the bushing see fig4 a axially spaced first and second inlet ports designated at 66 and 68 respectively located in the recess flat 64 extend through the bushing 40 into its hollow interior and also open into the inner portion 24 of the inlet passage 18 so that they are permanently in fluid communication with the inlet passage the center hole 38 in the bushing 40 which receives the stem 36 of the valve 32 is located within the recessed flat 64 between the inlet ports relatively large first and second windows designated 70 and 72 respectively are located generally in the front side of the bushing 40 see fig4 b the forward passage 46 in the housing 12 opens.