Thread Tension

Our blog series on machine quilting began in January and we’ve been talking about it ever since! We’ve looked at books on the subject, options for machine quilting design, how to audition and mark our designs, batting, backing, basting, needles and thread, workspace setup, quilting sequence, beginning and ending stitches and then spent the summer practicing what we learned.  We wrap up our series on machine quilting this week (at least until I realize I’ve forgotten something) with the important topic of thread tension.

When it comes to piecing or general sewing, we don’t pay that much attention to thread tension because – unless there’s some glaring issue – the stitches don’t show. However, when it comes to machine quilting, the stitches are visible on the front and the back. Good thread tension is critical.

Ideally, the top thread and the bobbin thread should lock in the middle of the quilt layers and form a perfect, even stitch on the front and the back.

But sometimes, the loops of the bobbin thread show through on the top and the needle thread appears to lay straight on the surface. This means the top tension is too tight and should be loosened.

Other times, loops of the top thread show through on the back and the bobbin thread appears to lay flat on the surface. In this case, the top tension is too loose and should be tightened.

How do we adjust the thread tension? There is a tension dial on your sewing machine numbered from 0 to 10. Somewhere in between is a line indicating the average or typical setting for good thread tension.

The higher the number, the tighter the top tension. The lower the number, the looser the top tension. So if the bobbin thread is showing on the top, loosen the tension by turning the dial to a lower number. If the top thread is showing on the back, tighten the tension by turning the dial to a higher number.

We talked about making a practice quilt sandwich a few months ago. One great reason to do this is to check the thread tension and make the appropriate adjustments. I also suggest making note of the settings that worked well for the fabrics and threads you were using. Superior Threads suggests drawing a line on the practice sandwich and marking it in 1″ increments from 0 to 10. Stitch on the line, starting with zero or no tension and increasing the tension at each increment until you reach the end or the thread breaks. This will give you a very clear indication of which tension setting produced the best results.

Some machine quilters minimize the impact of thread tension by routinely using the same thread in the needle and the bobbin. Not only does this reduce the probability of tension issues, it disguises them when they occur. While this approach has merit, it is still important to know how to adjust your thread tension when necessary.