I have a house built 1959. I am updating a bath. I can not get off the cap on the shower drain. There was a screw down drain visible in the shower. On the floor drain there was "nut" mounted on the floor drain. I can not seem to remove this "nut". There appear to be two "bolts" attaching it to the floor pipe drain. There are not screw heads or hexes on these bolts. I can not pry them up nor unscrew them. There are no visible nut on the underside nor are they any visible attachments from under the shower in the basement. They were clearly installed during the initial construction with the house. Bathroom remodel has stalled! HELP!

What I would do is use a dremel with a cutting disk or grinding disk to remove the old bolt/screw.You can get a new drain screw cheap and just replace it, hope this helps.

If that pieces will be replaced during the remodel you do not need to be gentle. How much do you plan to do, what will be removed?