3 Signs Your Sewing Machine Tension May be Off
Sewing machine tension controls the varying amount of strength (or lack of) on the threads to form a precise and balanced stitch, which is why having the correct sewing tension is essential for quality stitching.
As a general rule, adjusting your sewing machine tension is not recommended, so this is your Official Girlfriend's Guide to learning the three major signs that indicate your sewing machine tension may be off.
Your Stitches are Uneven or Loose
The primary indicator that your sewing machine is having tension issues is if your stitches are uneven or loose. When sewing, your stitches should be evenly spaced and tight on both sides of the fabric. If the stitches seem unbalanced or the thread pulls out when tugged on, there is most likely a problem related to tension with your sewing machine.
If the tension controlling your needle thread or bobbin thread is off, you may see the wrong type of threading on your fabric. Correct sewing machine tension will make your needle thread appear on the top of your sewing fabric, while your bobbin thread will appear on the bottom. If the opposite occurs, your problem likely stems from sewing machine tension issues.
If you pull on your bobbin thread and the thread unwinds without resistance, making the case fall, this indicates your bobbin tension is too loose. Vice versa, if your bobbin case doesn't move when tugged, the tension is too tight. Correct bobbin tension should unwind very slightly, making the bobbin case drop only an inch or two.
Once you've established your sewing machine has tension issues, go through this checklist of issues your sewing machine may have. Never attempt to adjust the tension on your sewing machine without help from a professional or unless you know precisely what you are doing.
Read more here on Fixing the Tension on Your Sewing Machine.