Gillette TTO razors have quite a bit of "clearance" built into them, and do not require any lubrication to prevent wear or improve operation.
Mineral oil dissolves and softens some of the soap and mineral "gunk" that can cause the screw or shaft to bind. Not actually lubricating metal-to-metal components, but rather helping to get rid of the crud that is the underlying cause of the problem.
A long soak in very hot water (just shy of boiling) does wonders if crud is your issue. An ultrasonic cleaner is helpful in getting the crud loosened as well.
Double check to make sure your head is square and the safety bars are straight. Any tweaks to the head geometry (as a result of being dropped) can cause the doors to bind when opening.
For my face and beard, it is hard to find a better DE shave than a Red Tip. Good luck with your restoration!
Brad - OGA
You must be willing to do the things today others won't do . . .
In order to have the things tomorrow others won't have. - Les Brown