So with that in mind, I was determined to figure out how I can fix what was my happy machine back to its good working condition. I played with adjustments again all Tuesday morning. Then gave up with a sigh that yes it will have to go the shop.
That's when I found the Craftsy class on sale, the one I've had my eye on for a several days, Design It Quilt It by Cindy Needham. All I can say is wow! In the second or third lesson she covers tension, and as I'm accustomed to a vertical bobbin, I was happy to have some good visuals on adjusting a drop in bobbin.
My problem with my machine, it seems, was the bobbin tension was not near tight enough. Even though I had been adjusting the spare bobbin case, I hadn't yet tightened it enough to really solve the problem and once I did, voila!, thick threads, thin threads, my regular Aurifil, all making lovely free motion stitches with just slight adjustments to the top tension! I have no idea why the bobbin tension became loose over time, but its fixed as far as I'm concerned!
[caption id="attachment_1182" align="aligncenter" width="300"]
front of quilt, photo adjusted to try to show black thread quilting on the dark fabric[/caption][caption id="attachment_1183" align="aligncenter" width="300"]
back of quilt, showing nicely formed stitches[/caption]Just another word about Craftsy...I had signed up a for a different free-motion quilting class and quickly discovered that there wasn't much new for me in that class. I contacted Crafsty about their class guarantee, and they refunded my money, no fuss no muss!