You know, now that I'm remembering, one of my 6000is got its chrome metal thread guide, that sits up over where you run the thread down through the machine, bent a little bit when one of the kids bumped it in some rowdy play. (They don't get to visit me often, or they would not be actding like that indoors!!)

Anyway, the little round bobbin thread guide on top was tilted, and the bobbins filled wonky. Yes.
I took it to the machine guy and had it straightened back up, and no more trouble with the bobbins filling tight and even.

How funny not to remember that.
I guess age does filter out our memories!
Sigh.

Thanks for the info. I will check that out.