Little thread blobs on back.
 

Every so often I get a thread blob on the back. Is it tension issue? I've tried adjusting, cleaning, changing needles. Everything I can think of. It doesn't do it on a sample. Just the real quilt. ????
I have one of those bohemoth machines that I'd need a truck to get in for servicing.
Anyone have any ideas.
Oh, it only does it when quilting,, not piecing.

is the thread blob from the top thread or the bobbin thread?

Are you free motion quilting? When doing free motion, movements are not as smooth as with regular sewing. Some machines are sensitive to these changes in motion, causing thread tension to vary.

No, not free motion quilting.
I don't know whether it is from the top thread or the bobbin because I always use the same in both when I quilt. How can I tell?

I just looked at one I did with variegated thread. It's the top thread that's making the blob. What does that mean? And why does it do it just some of the time?

Your needle size may not be compatible with the weight of thread you're using.

or...

If you are using a cone, you may need to reduce some of the tension as it feeds into the machine. You can do this by taping a paper clip to the back right side of your machine and running the thread through it first and then begin threading your machine.

Oh, thread size and needle size. hadn't thought of that. If I'm using 50 wt thread, what size needle for machine quilting?

What ply is the 50 wt thread? I use size 80/12 needle for 50 wt 2 ply. For 50 wt 3 ply I found a 90/14 works best for me when using a walking foot.

If you have a "behemoth", are you using the thread cutters on the machine?

If so, when you get a "blob" is that the same as what some of us usually call a "thread nest" (albeit, a little one) ... is it at the start of your next run of sewing after having used the thread cutters on the machine?

If so, I have gotten in the habit of using a little 1" wide piece of jumper fabric to stitch off onto.. and to start stitching from ... instead of using the cutters.

I was watching the Quilt Show (Ricky Tims / Alex Anderson) and she called the little pieces of fabric "starters" and "enders".

Leaders/Enders....Bonnie hunter makes great second quilt tops from these...I love the idea....

If you r getting eyelashes, your top thread is not on the paths correctly.....re thread.

I'm wondering if there's a burr on your hook or needle plate. Run your finger across the point of the hook (the thing behind the bobbin case, that goes around and has a point), and around the opening of the needle plate. If you feel a rough spot, you can polish it down with a very fine sandpaper -- about 400 gritt.

Thanks quiltedsunshine. I'll look and feel and see if I can find the parts you're talking about. It's just so odd. It does it randomly. At first I looked to see if perhaps it was always at seams. But there's no pattern to it. Some rows of quilting are just fine, and then the next might have several.