i recently plugged an oversized hole with jb weld and it worked fine. i've also done it with 5 minute epoxy. i found the trouble with bushing the hole is that the steel is hardened and i couldn't drill it or ream it. i get brass tubing and rods at a hobby shop, but the have to be available online.
i don't know where the thread is but i also wanted to line some scales with brass and the more knowledgeable people here gave me all sorts of caveats about how to do it, because of the flexing issue the brass is apparently liable to pop loose unless a way is found to key it in somehow. i didn't try it, yet.