TIL: Do not use a screwdriver in the notch to turn the shaft
 

Yeah. Do not use a screwdriver in the notch on the shaft of a Necchi to turn it. It will very slightly bend the edges of the notch so the hand wheel doesn't go back on. It works great, but gnarling up the end of the shaft is, as they say, an undesirable outcome. Good news! Fairly easily remedies with the big fat Fake Fingernail Emery Boards. I keep a selection of grits for when I need to undo a blunder just such as this. If manicurists only knew what they were missing.
I thought that would be nice hard steel, but I See That I Was Wrong In Thinking That. ( I'm considering this for the title of my autobiography...)
I guess the other good news was that this got the Resident Engineer involved and he fixed the blunder, and reassembled it.
It had a weird stall in the action that ended up being a bent bobbin shuttle. I replaced it with the one out of the SNU2, and it just hummed along. Don't know if it had it before SGW shipped it here and broke the otherwise very nice case or not.

That is what happens when you use the wrong tool for the job -- you learn something. Glad it worked out for you.
Mike

I have a babylock.............and the lady told me not to use a screwdriver---and to use a dime! It works!

I have found that an old class 15 bobbin works in a pinch as a screwdriver. Had one nearby when I needed a flathead but couldn't locate one thin enough & this did the trick nicely. I've used a dime before too.