annular flanges 29 and 31 projecting outwardly from the body a clutch assembly 33 is interposed between the air motor and the mandrel 39 s trailing end for coupling torque to the mandrel 21 rotation of the motor thus threads the mandrel downwardly through the tool body until the mandrel 39 s leading end engages the insert 11 and threads it through the prewinder 25 into the tapped hole 13 the clutch assembly has a diameter larger than that of the mandrel such that its lower end forms an annular shoulder 35 in accordance with the invention the installation tool further includes a sleeve 37 encircling the mandrel 21 and threaded into an upper section 39 of the tool body 39 s opening 18 an upper annular shoulder 41 of the sleeve is positioned to be engaged by the shoulder 35 of the clutch assembly 33 which limits further advancement downwardly of the clutch assembly after a few additional turns the clutch assembly ceases to couple the motor 39 s rotation to the mandrel and further threading of the insert 11 into the tapped hole 13 likewise ceases operation of the clutch assembly is described more fully below as shown in fig3 the adjusting sleeve 37 includes threads on its exterior surface to be threadable into or out of the tool body 17 this exterior threading is interrupted by three flats 43 44 and 45 separated by 120 degrees for use in locking the sleeve in a selected position to the tool body a set screw 47 is threaded through a threaded opening 49 in the body to abut against one of the sleeve 39.