Sewing machine tension issues on curves
I've used a domestic sewing machine for years and understand the basics.
My machine (both of them) does great for general sewing and straight stitch quilting. However, when I use the free motion technique and make curves the top thread shows on the bottom.
Okay, so I tighten the top tension and it helps but does not solve the problem.
Then I go back to start and loosen the bobbin tension and that helps but doesn't solve the problem. Even a combination of both, I can't seem to get it right.
Is something besides the tension causing this? Remember, it sews great otherwise.
When you loosen the bobbin tension, how does your straight stitching look?
I ask because I would be hesitant to change the bobbin tension if for everything else it looks good. (For me, I definitely need to leave a post-it-note on my machine reminding me to return the tension screw back to its original position.)
What I suggest is to stitch around your curves at a constant speed (both in the speed of the needle and the movement of your hands), possibly even slowing down just a bit. If your tension is good for everything else, the only thing that would be different is the movement of the quilt. Does that make sense?
Frequently, when we quilters go around curves we instinctively speed up. That pulls on the needle and the thread and could be the cause of your tension problems.
I've had a couple of quilting teachers specifically tell me (when I was first starting out) to stitch different motifs at different speeds (i.e. go around curves faster) but speeding up on the curves created the same 'eyelashing' or 'railroad tracks' that you're experiencing. The constant machine speed and hand movement cured the problem for me. If you have a speed control on your machine, try setting it at least one notch below 'full speed'.
The other thing that might help, if you're not already doing it, is to use the same thread in both the needle and the bobbin. This combination would require the fewest tension adjustments (if any) and it might help in isolating the problem.
Let me know if this helps.