rgh25,
When you try the soldering iron trick, you might try 50/50 mix of ATF and acetone and the drill press trick,but try tightening/loosening back and forth. They weren't put in super tight,since they had lock screw, and may turn a little tightening, which may break the "rust bond".Home Shop Machinist Magazine tested different penatrating oils and the ATF/acetone worked best, but you have to shake it up to keep it mixed.
Mike