I am looking for a variable speed changer for "V" belt drive on a drill press and other machines. This is basically a 3 part pulley on a jack shaft with a handle to move it. How it works is the top and bottom parts are fixed and the middle part moves up or down by belt pressure when the handle is moved. When the middle part moves that changes the ratio of the pulleys and also the speed of the output. I have seen one on a drill press years ago and an article in Home Shop Machinist (I can't find it now). Any help is welcomed.
See attached drawings.