Some suggestions for removing stuck screws:
Take precautions to protect the objects finish.
Fixture the patient so it can't move. V blocks and toolmakers clamps are very handy for round objects.
If you suspect threadlocker (Loctite, et al) trim the tip of a 25W soldering iron to fit the screw slot, and warm it that way. No Torches!
Use a screwdriver bit that fits the screw head perfectly. The screwdriver handles with the swiveling button on the end work well for camera stuff.
Use the screwdriver from straight over the screw and use your thumb or off hand to apply even pressure down on the screw and driver.
If the bit wants to slip or cam out of the slot, melt a little pine rosin onto the screwdriver tip. There are preparations like Vibra-TITE 470 anti-cam out fluid that you can try too.
In extremis, after you have tried all of the un-locking penetrants, heat and all proper technique you can muster, put the screwdriver bit in the chuck of a UN-PLUGGED drill press so that it can bear directly on the screw's axis (you may need a third hand here) and turn the chuck with your hand. Keep in mind that you have enough power to twist the head off of a regular 1/4" X 20 screw with this method, let alone a 0.8M camera screw.
If the screw breaks, thats another set of to-dos. Let us know how it works out.
If you can post some pictures of this adapter, we can see how its made. I think I'd like one too.
