Just throwing out ideas for you Ed. While your rambling anyway. This was the arrangement on the cross slide of my lathe. The one half of the nut is fixed, the other half rotates to take out the backlash. That part has two little spring loaded pins that alternately drop into the notches to hold the setting. A much more elegant way of tightening it up. The way yours was, pulls the nut out of alignment causing that vee shaped wear pattern. The Hardinge used a similar arrangement but I don't recall the particulars. Would be much easier to turn a round shaped nut to drop into this bracket, or if there's enough material bore out the existing bracket to take two nuts like this. Just rambling too.