Frozen screw...

[Roger Payne]

I had a few moments spare whilst working in the garage earlier & decided to see how long it would take to get the heavily corroded screw out of the volley sight range plate. The whole procedure took less than ten minutes, much of which was waiting for the assembly to cool enough to handle with my fingers after I'd heated it.

Firstly; clean off any loose rust with a wire brush before heating the screw - you can use rather more than you could if it was still in the woodwork, but not enough that it would affect heat treatment on a nice example (the screw is obviously scrap on this one anyway).
Secondly; douse in cold water to fracture the rust bonds between the screw & range plate threads.
Thirdly; gently warm to evaporate water, & then dip in penetrant (brake fluid in my case).
Ideally I'd leave it in penetrant for 24 hours or so, but I only had a few minutes, so that's all it got!
Fourthly: hold screw firmly in vice (vise in North America), & wind off the range plate using hand power, or a small set of grips if necessary (with the grip jaws padded to avoid damage to the range plate edges).

Give it a try. I'd be very surprised if it doesn't work. If the screw does get damaged then pm me as I can probably find you a replacement.

ATB.