[rotorwrench]

It sound like it might help to try and derust your tower. There are some mildly acidic solutions (usually with acetic acid or vinegar) or Evaporust which uses EDTA to chelate with the iron oxide that work pretty well.

The only other thing would be heat and cooling cycles to get the iron oxide bond to break down. This will also break down loctite products. Heat the part to no more the 250 F then cool it rapidly with water.

These methods will usually work to get stuff apart but it takes time. Parts that are fitted tightly together tend to weld them selves together with iron oxide build up between the two surfaces.

If the parts aren't to rusty, the penetrating oil should work. I guess is just depends on where that old tower has spent the last 75 years or so since the old A-bone went out of service.