MrsBoats

I found a nifty new machine that I'll be keeping as a backup-a Nelco Golden Stitch series, model number SZA-625f. (I posted about it over here: http://www.quiltingboard.com/t-154674-1.htm#4262295)

I've taken the back off, gotten it de-linted and oiled and so far, so good. Where I'm stuck is a mystery hole in the back. I found a screw top in the mechanism that I think that hole goes to, but I have no idea what it does. The two best guesses so far are some kind of tension, or it adjusts the zigzag width. Only I thought that's what the lever on top in the front did-maybe that centers the needle? It does make the needle move side to side, but I can't see that it's zigzagging, so now I don't know.

I know, I could take it to my osmg and let him figure it out, but A: I know for a fact he's now running more than a month out, and B: I'm sort of enjoying figuring out the mystery on my own.

I'd really like a manual for this but so far, the ones I'm finding aren't for this model number. Failing that, I'd be happy with sorting these two things out.