fig1 a zero backlash downhole setting tool 10 includes a mandrel 12 having a number of recesses 14 therein the recesses are illustrated in the figures hereof as four in number but it is to be understood that other numbers of recesses 14 are also employable each recess 14 includes two ends 16 and 18 see also fig3 ends 16 are larger cross sectionally than ends 18 more specifically and addressing the shape actually illustrated but recognizing that the specific shape is not intended to be construed as limiting the cross section of end 16 is in the shape of a trapezoid end 18 is also in the shape of a trapezoid but the area defined by the trapezoid at 16 is greater than the area defined by the trapezoid at 18 in one embodiment each side of trapezoids at end 16 are larger than each side of the trapezoids at end 18 mounted at the mandrel 12 and still referring to fig1 is a device 20 such as a seal or any other axial force settable tool to be set by the downhole setting tool 10 as illustrated the device 20 is a seal but it is to be understood that any device requiring axial compression for setting can be set by the downhole setting tool 10 as illustrated the device 20 is integral with a plurality of fingers 22 the fingers are deflectable radially inwardly at least partially into recesses 14 during use of the downhole setting tool 10 facilitating flexibility of the fingers 22 in the illustrated embodiment is a flexibility.