illustrated in fig1 a window generally designated by reference numeral 10 and which window 10 includes a window frame 12 and a sash 14 an operator 16 is utilized to open and close a window which is of the casement type operator 16 as may be better seen in fig2 a and 2 b includes a base 18 which has a plurality of mounting apertures 20 as is conventional base 18 may be secured to the window frame by screws or other suitable mechanical fasteners mounted on the upper side of base 18 are posts 22 and 24 for reasons which will become apparent hereinbelow base 18 also has a aperture 26 in the illustrated embodiment operator 16 includes a first arm 28 and a second arm 30 arms 28 and 30 are conventional in the art of window operators arms 28 and 30 are secured by rivet 32 arm 28 has a first end generally designated by reference numeral 34 and forms a portion of a worm wheel 36 as is well known in the art it will be noted that there is provided an aperture 33 in worm wheel 36 and which aperture 33 overlies aperture 26 a shim 38 is placed between worm wheel 36 and base 18 an upper securement member 40 works in conjunction with a lower securement member 42 to secure arm 28 in position in this regard upper securement member 40 has a threaded recess which is designed to screwthreadedly engage with threads 44 on lower.