After some thought, I think it's not a timing issue--it sews well and doesn't skip stitches--but a needle issue. I wonder now if someone didn't put the wrong needle in at some point? There's a pack of original Kenmore needles in there, and they look like typical needles (the HA whatevers that are so common) but I haven't compared them side-by-side yet.
Your Domestic sounds interesting-I hope Iris can post a picture! The bobbins for this one remind me of the ones that go with my Pfaff 130-narrower/flatter, but bigger around.
An aluminum machine thread would be interesting-I didn't know there were that many out there!