I would look at the bobbin tension - make sure it is not too tight, and then re-adjust the top tension to balance to the corrected bobbin tension. Only adjust the screw on the bobbin case 1/4 turn at a time. You want the bobbin to drop down like a spider on a web without the bobbin falling out of the bobbin case. Adjust the tension to achieve a balanced straight stitch - not FM.
Tension and thread breaking is the most frustrating issue of sewing!

Lola,

I have the Juki 98Q on my quilt frame and I can tell you that I've spent YEARS dealing with thread problems! No joke! I have determined that it's very temperamental with thread choices and the ONLY thread I can use is Superior Threads-King Tut (on top) and Superior Thread-Bottom Line (in the bobbin). I have lots of spools of other brands that I've tried and can't use for quilting. [It's a bummer, but at least I found what works!]

With that said, if you've been using the silk-Mettler thread and it's been working, then I think you need to go find some more of that for this project. You'll have to try the Sulky in the bobbin with the Mettler on top and see if it works...If it does, then go ahead. If you have lots of thread breakage, then take the Sulky out and go back to what you had been doing.

I'm pretty sure that in the past I've posted my findings here about thread & the Juki. Try a search for 'Juki 98Q' and see what comes up. I spent so much time working out my issues, I hoped to help someone else with my findings.

I can commiserate! Keep trying!
Jennifer

I have a Juki TL98Q on my frame, too, and it isn't as picky about thread. I use a lot of Coats & Clark cotton from JoAnn's, and occasionally poly or rayon machine embroidery thread if I want a certain color.

30 wt thread is pretty heavy...what weight is the Mettler? You should use the same weight in the bobbin and on top.

I have tried to FMQ with Sulky Blendable thread, and never had any luck, either on the frame with the Juki or sitting down with the Brother. It just doesn't seem strong enough for the higher speed and movement of FMQ or something. I finally used it up piecing.

Donna

Thank you for your quick answers. I have heard people talking about adjusting the bobbin tension, but I didn't know how much was too much, and I've been afraid to touch it. I like the image of a spider, I can try that.
Jennifer, I do remember some of your posts about thread, I'll look those up now. Thanks for the reminder.

Donna, I think the Mettler is 50 wt, but I'm not positive. I think I remember learning that the lower the thread weight the larger/heavier it gets, and the larger the needle size the larger it gets - is this right?

I know this sounds very naive, but when buying thread I've really focused more on color than thread weight, and generally I've been pretty lucky buying whatever was sold at LQS. Obviously not this time, so now it's high time for me to pay attention to thread!

Thanks again for your replies, it helps to vent a little and get some advice and sympathy.

Lola, you're right - the lower the # the thicker the thread.

I happened to be quilting with Mettler thread yesterday. It was 50 wt and worked great in my Juki!

Donna