I’m conflicted- it all sounds very intimidating (would hate to mess up a revolver with sentimental value) but you’ve gotta learn somehow. This is one of two revolvers we inherited - this along with an older 66. It would be worth understanding better how they work.
If you’re uneasy about a complete disassembly I’d find an experienced S&W revolver smith or spend some time reading Jerry Kuhnhausen’s excellent book.
All the vintage 34’s that haven’t been fired much (that I’ve disassembled) looked like varnish inside or are completely dry. Rimfire J frames aren’t known for their smooth actions, due to the higher weight springs. They can be improved some, but not much.
Do not swap the yoke screw with another screw, it is fitted to the yoke and will make a mess of the yoke end shake and correct drag of the opening of the cylinder. I’ve seen dozens ruined because some “gunsmith” or owner didn’t know.
Brownell’s has a set of S&W revolver specific screwdrivers, they fit the best of any I’ve used.
