I learned many years ago to use an impact screwdriver when trying to get very tight screws out. Not the electric impact driver, because they are too fast. I have an impact screwdriver that I bought from an auto parts store. It has several replaceable bits and an adapter for socket wrench sockets with it. Place the correct bit in it, place it in the flat, Phillips, or whatever in the offending screw head, turn the body of the impact driver about 10 degrees in the direction that you want to turn the screw, and hit the back end of the handle part with a hammer. The impact forces the bit tightly into the screw head and at the same time imparts a twisting action in the direction of your choice. One or two hits is usually all it takes and the screw isn't even damaged in the process. It's one of the best $16 tool investments that I've ever made. I use it before I've beat up the screw head with other methods, so it has a better chance. I don't wait until I've effectively killed my chances of using the flat, Phillips, or other slot in the screw by trying and trying again to get it out other ways. It gets used on my woodworking tools, metal projects, printing presses, and about every other time that I have difficulty removing a screw or small bolt now.
Central North Carolina
Last edited by CharleyL; 07-01-2019 at 12:21 PM.