Bobbin tension
 

Just got my new Juki TL2010Q yesterday and bobbin thread is pulling to the top. After 6 years of using a totally computerized never needing adjustment machine I don't know what causes this. The top thread is sewing beautifully but bobbin thread is showing on top as well. Book, if you can call it that, shows me how to adjust top and bobbin tensions but not for a specific issue. I think I am going to just love this machine when "I" know how to use it.
Thanks,
Evelyn

If the bobbin thread is showing on top, either tighten the bobbin tension or loosen your top tension.

I always start by adjusting the top tension. I very rarely have to adjust my bobbin tension, and I keep a separate bobbin case just for that reason and leave my regular case set at the same tension.

There is a tool that is used to set bobbin tension. I've "heard" that it is not worth the cost. But I have always thought an inexpensive tool would be nice so you could set bobbin tension accurately if you change it.

I would take it into where I purchased it and have someone help you learn the tricks of dealing with tension on this machine.

If you're talking about the Towa bobbin case tension gauge, it doesn't actually set the tension. It merely tells you how tight or loose your tension is. You have to experiment with the gauge and your machine to see what tension (or range of tension) works best with the combination of thread, needle, machine, and fabrics.