I attempted to replace a bathtub drain using the usual tool that grips the cross members inside the drain only to have them immediately break off. Is there anyother tool available that can grip the inside of a drain so I can replace it. No access to underside of tub unfortunately.
The above link is a picture of what you might be looking for. I have one in my arsonal. I always try the dumbbell first, then the above mentioned tool. If neither of them work I use my jigsaw or sawsall to to make vertical cuts at 3-9-12 o'clock positions in the old drain, then pry it out with a screwdriver. Be carefull so you dont cut thru any plumbing you don't wish to replace.