Macybaby

Interesting - I've only had my Juki 2010 since December, and when I get this, it's the top thread that is the problem.

When I use the auto cutter, it cuts the bobbin thread very short, but leaves a tail on the top thread. If I pull the piece to the back, this tail will pull up to the top and behind the foot. Then when I start the next piece, I put my finger on it so it does not get sucked back down to the bottom side, and sew away.

I do have to trim these top tails afterwards, but that is nicer than having that nest on the back side.

Try a different color top and bottom thread, then you'll know for sure which one it is.

I went up and did a bit of test sewing. And it's always the top thread that is the problem on my Juki. And only if I do not pull the fabric all the way out of the machine to fully pull that "tail" out of the bobbin case area.

I was paper peicing this weekend, and really did not want that nest, but wanted to use the cutter. So I experimented quite a bit.

Bilben

I bought the Juki F600 a few months ago and my stitches looked uneven like yours. I discovered the pressure foot dial (after weeks of wondering why my stitches were crooked when all the reviewers seemed to rave about the great even stitches) and after adjusting it my stitches looked much straighter. Hope this works for you too!