FWIW, take the worn out nut (internal threaded part of a leg vise, Chuck it up in a lathe, bore it out a 1/4 inch larger than the OD of the thread, drill about 8 to 10 holes in various places thru the outside. Countersink the holes from the outside. wrap the outside tight with multiple layers of Aluminum foil then Duct or Masking tape, SMOKE the thread real well with straight Acetylene flame, position the thread in the center of the Nut, then pour it full of hard High Speed Babbit. Wallaa, a new nut.