Hello all, I have been recently diving into the world of watch repair and have worked up to servicing my aerospace gmt. My question regards the going barrel. It is marked "do not open" and I am curious as to the best way to go about servicing the mainspring. Are they really good for a "lifetime" or should it be serviced. Ive read that its a pain to try and refit the barrel lid but if anyone has any info it would be a lot of help

I use someone for my restorations, but, they are not lifetime. 60 year old mainsprings just won't cut it.

Thanks for getting back to me butch. Have you had any luck disassembling and reassembling a "do not open" barrel?

Not at all, but with a lack of parts no idea what is left but to try it.

Thanks again for getting back to me. I think I'm going to just go ahead and try my luck with refitting the old barrel. I can't source a replacement so I don't want to push my luck