Hey JT, I recently retrofitted the Z axis on my 1990 Shoptask mill. I Completely eliminated the worm gear and the rack and pinion which was part of the original design. the new configuration works very well. I am attaching a few photos, thought there may be a few individuals who may be interested. One question I would like to know is the approximate weight of the machine with out a stand. Thanks a lot. Hope the pics are attached