Yep. I have a Smith-Corona Classic 12 on my desk. Purchased new during grad school. Using it pretty much like you are but perhaps not so much for letters; but you’ve given me the idea.
I arranged for a local repair shop to fix the ribbon spool mechanism which didn’t move the ribbon while typing. They were unable to do so as they could not find parts. I took it home, took off the bottom cover and found the wayward gear that broke off the spindle holding the ribbon spool. With a little Super Glue spotted on the bottom of the spindle. Working fine! Now to see if I can clean it a bit. Down to me, I know.