Tightened it. In searching for stuck threads in the bobbin area, I started to wonder about the bobbins. A few of mine are old, the rest are new. Some seem taller than others, and I thought the old ones were shorter. Got out DH's dial caliper to check. They ranged from 88 to nearly 94 microns tall (thick?) The oldest one was right about 90/90.5, so that sunk that theory. Then started looking at the bobbins, where the axle, if you well, joins the rims. The oldest bobbin was nearly smooth. Some newer bobbins had an inset bevel, effectively making it smooth. The bobbin I did most of my testing with tonight, .had a slightly raised joint. I did a bit more testing, not conclusive, but I think the raised joint may be interfering with the spin of the bobbin in the case. The thread snarls started at the close of my last project...likely with a freshly wound bobbin. Perhaps one of the knobby ones. That and that machine likes really long thread tails...about 6-7 inches, to start. I keep wanting it to like 3" tails! I will try to do more testing tomorrow after work, and will get pics of the bobbins to post.