bridgeports are good machines to convert atleast that what i hear.
if the axis' are that hard to turn, it probably wouldnt hurt to take it apart(provided you can put it back together the same way it came apart) and give it a thorough cleaning while inpecting the parts' condition then give it a good greasing and all should be ok.
as far as converting it goes, anythings possible if you think about it hard enough
