Hi Fleetwing! I had the very same issue when I first bought the typewriter, the bar that holds the gear-turning worms didn't actually touch the gears and was very resistant to manual turning with the knob. However, when I tinkered with it I found that that bar actually angles up and down(when looking at the bottom of the machine) to activate either gear. So it kind of "snaps" at the appropriate crooked angle to catch the left or right gear. I'm not sure if that helps you any. That may not be what it's supposed to do, but in pretty sure that is how it works.

The machine has catches that are supposed to automatically switch feed direction upon reaching the pins in the ribbon, which was what was snatching on the gears and causing resistance to knob turning. I'm uploading a video of the mechanism that I will attach once it's uploaded!

Other than that one problem, it's a great typewriter! It's my oldest and best working manual.

Here's what it's doing:
 

Teran M. wrote:

Here's what it's doing

Your ribbon is not properly threaded through the vibrator in that video. I am not sure if it was like that in your testing. Is that old dried ribbon? Decades old, really dried out ribbon can drag and cause issues. I would double check your threading, and if that is old ribbon that came in the machine, toss it. I would then check that the spools and nothing on the top part of the ribbon feed mechanism is binding. There could be other issues, but I would check these first.

Are they metal spools or new plastic ones?