I apologise for using my blog to answer a Facebook query, but in keeping with the spirit of Typospherians helping one another out, here are some images requested by JP Huard ("Anything Goes").
JP posted to the Facebook Antique Typewriter Collectors group today: "Does anyone have an Erika Model M (or 6)? I'm hoping to get a picture of how the carriage lock lever screws in/is connected, I have an idea in mind but would prefer to check if possible before playing around with it ... (pic relevant, it's the one my girlfriend got me this Christmas)."
It took me all of two minutes to take the photos JP wanted but after two hours of trying to load them on to Facebook, I gave up and put them here. Please excuse ...
Here are JP's images:
JP then wrote: "I appreciate the pictures you put up, I wish I'd been more clear with my question ... My carriage lock is in fact in place, but pulls straight out.
"There's a square portion before the threads, which goes into another part that's more visible from under the machine's bottom cover.
"It would stand to reason there should be a nut on the threads to keep this piece captive/in place, but I don't know the angle at which the piece is supposed to be positioned (relative to the carriage lock lever). Also just want to verify that this spring goes over top of the groove on the black piece with the square (for lack of a better way of putting it).
"I'm inclined to believe this will be the proper position for how they mate together but I have no real way of being sure short of asking/seeing another."