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How can I get my tension properly adjusted?

First, learn how to distinguish tension issues from other machine problems before making any tension adjustments. Tension imbalance is the cause for the following problems:

***Rarely (almost never) are tension issues fixed by re-timing the machine!!***

Before diving into the many factors that can affect your tension, let’s first review the basic procedure to follow when your tension seems imbalanced:

    1. Check the thread path. Is the machine threaded correctly?
    2. Make sure the top thread is “snapped” between the tension disks, not riding on top of them.
    3. Clean out the bobbin case. Every bobbin change, remove lint that may have built up inside the case and under the check spring. Also check under the tension finger on the outside of the case. Thread fibers can build up under the finger, reducing the tension on the bobbin thread.
    4. See if you can achieve proper tension by adjusting top tension first; if the desired look is not achieved, adjust the bobbin case tension. (Remember that you can adjust the top tension knob a half-turn or more before you’ll see much impact on the thread tension; however, the bobbin case tension is much more sensitive and should be adjusted only about 1/8 of a turn at a time.)
    5. If the top thread “lies” on the quilt top, it’s winning the thread tug of war. Start by loosening the top tension. If you have extensively loosened the top tension and see little or no impact, then tighten bobbin case tension. Be sure that some tension still exists on the top thread. You should feel resistance as you pull the thread through the needle’s eye.
    6. If the bobbin thread “lies” on the quilt back, start by tightening the top tension, which will cause the top thread to pull a little harder. Usually this will solve the problem. However, if your thread is fragile, increasing the top thread tension might cause your top thread to break more often. In this case, you’ll want to also loosen bobbin case tension so that it’s not putting as much stress on the top thread. If you’ve tightened the top thread extensively and are still not seeing results, then also loosen the bobbin tension so that the top thread can pull the bobbin thread into the quilt’s layers.
    7. Use the “bobbin drop” test (see below) as a starting point, but be willing to adjust bobbin tension beyond that, depending on your thread choice:  Yo-yo test results should start at:  3-4 inches for pre-wound bobbins, 4-5 inches for plastic bobbins, 5-7 inches for metal bobbins
    8. Consider keeping different bobbin cases for different threads—cotton thread is weaker than polyester, for example, and will usually require looser tension in the bobbin case. Depending on the thread and its thickness, sometimes it is loosened considerably! Use a permanent marker or fingernail polish to mark the cases for different threads and adjust each one accordingly.
    9. Try using a light-weight bobbin thread, such as Superior’s Bottom Line, or a fine lingerie bobbin thread.
    10. Invisible nylon or polyester thread can be used in the bobbin to help with tension issues or difficult thread color decisions. Wind the thread on a metal bobbin, but only wind it half full to prevent stretching. (If you have a manual bobbin winder, also loosen the tension knob on the winder before winding invisible thread.) Loosen the bobbin case tension considerably. If you’d like to use the invisible thread in the needle, you’ll also loosen the top tension by as much as a full turn or more.
    11. Carefully examine the front and back after testing your thread choice; some very fine threads may appear to create bad tension, when in reality, you are just seeing the thread inside the needle’s hole. You should actually be able to feel incorrect tension with your fingernail by running it along the top or bobbin thread; it will make a clicking sound as your fingernail catches on the thread bumps left by imbalanced tension. Large needle holes typically will close up after the first washing, and can sometimes be coaxed closed by running a fingernail over the hole.

Many factors contribute to maintaining consistent tension. The most obvious factor is thread choice. However, many other variables can also have an impact on thread tension, including:

Fabric content
 For example, tightly woven fabrics such as batik can create uneven tension caused by the needle’s scarf entering the fabric and pulling it up and down. Try slightly loosening the fabric between the rollers, and making sure your hopping foot is set to the correct height for thin batting.

The hopping foot should be adjusted so that when you lower the needle to its lowest position using the hand wheel (not your single stitch button) one business card should easily slip under the foot. On the other hand, if you use a high loft batting, the foot may need to be raised to accommodate the extra thickness. Just remember to reposition it when you return to normal quilting.

 Unwashed fabric with sizing still in it can also impact stitch quality. With stiff, heavily starched fabric, the thread lays on top of the fabric instead of nestling between the fabric’s fibers.

Fabric tautness
Fabric that is too tight between the rollers also doesn’t allow the thread to nestle into the fabric; instead, try slightly loosening the fabric layers.

Batting content and thickness
Flat battings such as thin polyester and cotton don’t provide a great deal of “air space” for the thread to lock between the layers, especially with longer stitch lengths. Try a fine weight thread, a batting with a bit more loft, or even increasing the number of stitches per inch.

Direction the machine is moving
The machine’s hook rotates in one direction only, even though the machine can be maneuvered in any direction. Therefore, in some instances the machine is actually stitching “backward”, almost like holding the reverse button on a traditional sewing machine.

For example, if you stand on the free hand side of the machine and quilt a straight line to your left, the tension will not be quite as perfect as if you moved to your right.

We recommend that you generally move from left to right on the free hand side of the machine, and from right to left on the pantograph side. (Yes, this means that even though your pantograph pattern may have two rows of the pattern printed on the paper, you should complete the first row, tie off, and return to the far right side of the table to complete the second row.)

You may be able to eliminate this directional tension imbalance by tightening the top thread tension slightly, or by using a fine weight bobbin thread. Unfortunately, all the other factors play a role in the process as well.

Needle flex
If your movements are jerky or you are moving faster than the stitch regulator or motor can keep up with, the needle may flex as it enters and leaves the fabric. Strive for smooth, consistent movement, and adjust the motor speed if you are in manual mode, so that the motor keeps pace with you.

Also, needles smaller than 4.0 will have more flex in their shafts, increasing the chance of imbalanced tension.

Machine speed and stitch length
With traditional sewing, different fabrics and techniques require different stitch lengths. The same holds true for quilting. In some instances, a long stitch length such as 6-8 stitches per inch will create pull and puckering on the fabric, especially if thin batting is used.  Try increasing the stitches per inch to 11-12. In manual mode, strive for consistent length as well.

Spool mount
Study the thread and determine how it is wound around the spool. “Cross wound” thread typically performs better mounted vertically (resting on the back spool holder). On the other hand, thread that wraps around a spool in a continuous circular pattern performs better mounted horizontally. This allows the thread to feed off the spool without creating a corkscrew effect that can cause tension trouble and thread breakage. Check out the horizontal spool holder accessory available from APQS.

Humidity
Natural threads such as cotton and some rayons can literally dry out in arid conditions, making them brittle and more susceptible to breaking. Some quilters “re-hydrate” threads that are misbehaving by storing them inside a plastic bag in the freezer overnight before using them. Others have success taming unruly threads by treating the spools with liquid silicone, available in the notions department of most sewing centers (Sewer’s Aid is one well known brand.)

Thread content
Each thread has unique properties that will require tension adjustment. Even thread color can impact your tension and thread breakage! (For example, some dark colored threads such as black, navy, brown and even scarlet can tend to break more frequently. More dye is needed to achieve these colors, which weakens the fibers of some thread.) Thread quality also plays a stake in tension.

For example, some quilters successfully use serger thread in their long arm machines. However, this thread is not designed for heavy wear and the stress caused by traveling through fabric and batting—that’s why three or four strands of the thread are used in sergers. Use high quality thread from a respected manufacturer for best results.

Different top and bobbin threads
Mixing thread varieties on the top and in the bobbin often will require tension adjustment. For example, a pre-wound bobbin usually contains polyester thread, which is very strong. If you tried cotton thread with a pre-wound polyester bobbin and made no tension adjustments, the bobbin will usually win the thread “tug of war” and either pull the cotton thread to the back or will break the cotton thread.

If you tried to tighten only the top cotton thread tension, it will most likely break. You’d have to also loosen the bobbin case tension to give the cotton thread a chance to pull the bobbin thread up into the quilt’s layers.

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