Thread tension is essential to beautiful embroidery. Do you
know what it looks like?
We don’t often look at the back of our embroidery but it can
tell you a lot about your thread and bobbin tensions.
Ideally, you should stitch a satin-stitched alphabet that
runs both horizontally as well as vertically. The letters A or H are good
choices.

If you stitch out the letter A, on the back of the
embroidery you should have two areas of upper thread color (showing black here)
with the white bobbin thread in the middle. This is considered perfect tension.
When upper thread and bobbin tensions are ideal, you will
have no white bobbin thread showing on top. Yes, you could color the white
spots with a marker or use the same color of thread in the bobbin but that doesn’t
correct the problem.
Before messing with the bobbin tension, make sure the
machine is threaded properly and the bobbin is seated and threaded properly.
Clean out the bobbin area, another problem spot. Even the
slightest fleck of lint can affect your embroidery tension. You can see a
bobbin case cleaning tip here.
Maybe not so surprisingly, needles and stabilizers can also
mess with your tensions. If you are not using the correct kind of needle or the
stabilizer is wrong, your embroidery will likely suffer.
Nine times out of 10, threading
issues or a dirty bobbin area are the culprits.
Your bobbin case has a screw that
adjusts tension, but I would not recommend messing with that unless you have
two bobbin cases. They can be particularly finicky. Keep one original (mark it)
and play with adjustments on the other. That way, you at least have one
unadulterated bobbin case but only as a last resort.
Debbie SewBlest