I don’t have any stripped screw pliers, and i have been amazed at the tools that are abailable in that thread.
The brace i first asked about is in excellent condition, except a little gummy. It’s currently soaking in atf. I ordered a second one off eBay, due to arrive any day. In the pictures it looks complete, but in rough shape, lots of rust. Actually it looks like it was buried. So i’m going to experiment on it. Got it for a good price, only way to go is up.
Getting both of these for less than i paid for the first one.
Let us know the results of the soaking.
I found an interesting video where the host was showing two of these corner braces. On one of them, the cover dome had apparently been replaced by a home-made cover and the rivets replaced with screws. The owner may have destroyed the original cover trying to remove it. The gears were re-greased with what looks like the old vintage yellow Lubriplate (I have a nearly full can of that stuff from the 1950s--they don't make libricants like they used to, and with some products like this, that's a good thing). I also saw a photo of a really old one that was made with no cover at all. The point is that these two gears are substantial, and so it's difficult to imagine how they might be damaged from normal use. There's an excellent chance that yours is probably gummed up inside. ATF or ATF/acetone mix is the GJ universal cure-all. WD40, which also acts as a grease solvent, should work too.
If by some chance there is damage to the gears, how would one fix that anyway? I found a video of someone repairing a Bergman, but the gearbox was already open, the housing had already been broken and brazed, and the mechanism was like a u-joint, not gears. It's an interesting video nonetheless, although the fellow was something of a brutish hack.
. The job resulted in a usable tool, but having little or no collector value.
As is typical of youtube videos, finding one showing an extremely difficult task is next to impossible, or they'll skip over showing the difficult part because they don't want you to see what a struggle it was for them (it's an ego thing, I think; "see how easy I did that?"). I couldn't find any video showing the removal of one of these gearbox covers. Even if you were to get inside, it's unclear how you might replace a damaged gear. Of course, if it's a collectible, replacing gears is not as critical. If it's intended to be a user, there's still enough of these corner braces out there to find one in good working condition. In any event, I think that enough soaking in the right lubricant/solvent is going to get the job done.