Kwiltr

That sounds like it is a backlash problem. I have a HQ Sweet Sixteen and had the same issue. I understand the machines we have are the same. HQ Tech Support helped me with this. If your bobbin case doesn't look like mine in the picture, this won't help you. If you decide to try this, please note the bolded portion below. I took these pictures when my machine was having the issue you described. Sometimes it created a ball of thread like shown, and sometimes it was just a strand wrapped around the center post of the bobbin case. Inside your bobbin case you will see a flat piece of metal shaped like a sort of hook or semi circle which is called a backlash spring. It applies pressure on the bobbin and when adjusted properly, applies just enough pressure to prevent the bobbin from over spinning in the bobbin case. There is an adjustment screw that you can adjust from the outside of the case to increase the pressure the spring applies to the bobbin. Try adjusting it in SMALL increments at a time and retrying your stitching to see if you can get it so it doesn't backlash on you. When you adjust it, do so with the bobbin in the case and hold the case with the open face facing upwards. When you turn the screw you should see the bobbin raise a little in the case. Replace the bobbin into the machine, bring your thread up to the top. BEFORE ATTEMPTING TO SEW always make sure you can pull the bobbin thread freely from the bobbin case while it is in place in the machine. If you can't, you have adjusted it too high and you will damage your machine if you attempt to sew with it. You would need to remove the bobbin case from the machine and turn the screw back and reduce the pressure on the bobbin.

Other suggestions I was offered include using Magic Genie Bobbin Washers, which I've never tried, so can't attest to their success.

Hope this helps you, I know how frustrating it can be.

just a clarification...the screw you adjust is not the one you see holding the spring inside the bobbin case, but is the screw that is accessed from the outside of the case recessed on the back of it. Just another note...I didn't have this problem with my machine when I first got it, but it showed up when I switched to a new thread that was much finer than anything else I'd used before, I.e. Superior's Bottomline which I think is a 60 weight.