Not specifically a reno, but working on car parts for my 1969 Thunderbird.
Bought some spare used parts to customize, while retaining all the original parts.
One of the parts is an armrest for the front bench seat. I want cupholders, so i am going to fab it up. The guy who pulled the parts out of the donor car in Florida had to cut off the seat mounts, as he could not remove the 4 tapered screws.
I looked it over the other night, and could not loosen them either. Took the piece out to the garage and liberally sprayed wd40. Then tonight mounted the piece in the bench vise. Got out the impact driver (manual, not air) and a hammer. Put on the safety glasses and work gloves.
Gave each screw a good pounding, and 10 minutes later - success.
Love it when you take your time, leverage the right tools, and solve a problem!
On to cutting up the armrest to allow mounting modern cupholders.