TIPS FOR ADJUSTING TENSION
Most longarm machines are capable of producing balanced stitches that lock in the middle of the batting layer and that are equally attractive on the top and back of the quilt with commonly accepted brands of machine quilting thread. Before adjusting your tension, you need to make qualitative assessments of how the stitch looks on both the top and back of the quilt. To get the desired stitch quality and to meet your expectations, ensure your machine is threaded in accordance with the manufacturer’s guidelines and then follow these steps in sequence:
HOW TO TEST BOBBIN TENSION
You need to set the bobbin case tension for the thread type being used. It is imperative that you have the bobbin tension correct before you make any adjustments to the top tension.
RULE OF THUMB
With a full bobbin inside the bobbin case, hold the bobbin case in the palm of your hand and gently lift the thread upward, the bobbin case should not leave the palm of your hand.
HOW TO ADJUST BOBBIN TENSION
To get to the above "rule of thumb" it may be necessary to tighten or loosen the bobbin case tension. To do so, adjust the larger of the two screws on the side of the bobbin case
(right to tighten, left to loosen).
With cotton and polyester threads, it is best to tighten the bobbin tension until the bobbin will lift out of your hand. Then loosen the bobbin case tension screw a minute of angle or two at a time until the bobbin will not lift out of your hand. You need to find that “breaking point” where turning the tension screw a minute or two to the right causes the bobbin to lift out of your hand and then turning it a minute or two to the left and it will not lift out of your hand. That is the ideal setting for the bobbin. Note: When an adjustment is made on the bobbin case, the result of the adjustment should be apparent. If a change isn't noticed, then the bobbin case is suspect.
ADDITIONAL CHECK ON BOBBIN TENSION
Lay the bobbin case down flat like a bowl with a bobbin in it. Verify the bobbin does not stick up above the sides of the bobbin case more than is pictured on the right.
The cause of the bobbin case being too high in the bobbin is usually an incorrectly installed anti-backlash spring (aka no-backlash spring). The anti-backlash spring is pushing the bobbin up too far.
If the bobbin is above the sides of the bobbin case/bowl, remove and inspect the spring to make sure it is not damaged. The most common damage to the spring is bent “ears” (aka tabs). If the spring is damaged, replace it with a new one or an easier to use product called “ABM International Anti-backlash Disks” or “Magic Genie Bobbin Washers”. To use these disks or washers, remove the anti-backlash spring and drop one into the bobbin case. The end condition that must be met is that the bobbin cannot be higher than the sides of the bobbin case/bow.
HOW TO TEST TOP TENSION
Take the thread out of the needle and pull the thread along its path. It should pull smoothly, without jerks, which indicate an obstruction along your thread path. You should not have to tug at the thread, but it also should not pull through without some tension on it. Lighter top tension will help you run threads such as metallic, monofilament, and Bottom Line.
HOW TO ADJUST TOP TENSION
The light grey pre-tensioner knob should be flush with the screw and is set at the factory. Do not adjust it.
The silver rotary tension knob may have to be adjusted for the weight of your top thread. Tighten the silver tension knob, by turning to the right, a little at a time and then test for results.
TENSION CHECK SPRING
The tension check spring on the main rotary tension should be set between 10:30 and 11:00. The straight section of the spring that first comes out from behind the rotary tension wheel is what you should focus on for this setting.
1) This tension spring needs to be set strong enough to take slack out of the thread so the take up lever and check spring can pull the bottom stitch tight. To strengthen use a small screwdriver and insert it into the end of the main tension shaft and turn slightly to the right.
2) If the spring is too strong, the result will be "eye lashes" when sewing a small circle. If "eye lashes" are present, the check spring is set too strong, and the check spring must be turned slightly to the left.
3) If the check spring is excessively strong, it will no longer bounce up and down while sewing and must be loosened.
This guide on tension adjustments was copied from Superior Threads website. If you want more great information on threads, tensions, problem solving, etc, please go to www.superiorthreads.com and look under the “education” section. Bob Purcell is an amazing teacher and shares a wealth of great information!
IT’S TIME TO TEST SEW
You will want to sew a little and check your stitch quality before you proceed to quilt. Remember the old saying, “measure twice, cut once”? It applies here.
- Test using the same backing, batting, and top fabric as the project you are getting ready to quilt. You may want to lay a piece of fabric on the excess backing and batting near the top or side of your quilt.
- Check that the tension on your quilt is slightly relaxed. You’ll have less thread breakage and better stitch quality.
- Sew small circles because they are especially good for detecting problems. Evaluate stitch quality on the front and back of the quilt and make adjustments as necessary. NOTE: highly contrasting your thread with the quilt top or backing is going to accentuate imperfections. You will also want to avoid high contrast between your top thread and your bobbin thread. If your top is very dark and your backing is very light or vice versa, you may want to quilt with a medium toned thread. It’s ok to use slightly different colors on the top and bottom, but you’ll want to have similar value (lightness or darkness).
- To get a quality stitch, proceed to adjust the rotary tension knob, a little at a time and test.
- NOTE: Lighter top tension will help you run threads such as metallic, monofilament, and Bottom Line. The important part is BALANCING the tension on the top and bobbin.
Final note: "pokies" mean tension is too tight on the side the pokies show up. To fix "pokies" on bottom, tighten top tension (or loosen bobbin tension). To fix "pokies" on top loosen top tension (or tighten bobbin tension). A balanced stitch most likely will have pokies on both sides of the quilt. To minimize this problem, we recommend that quilters use thinner threads such as Tex 50 or 60 threads.
The first remedy assumes your bobbin tension is set correctly. (If not, use remedy in parentheses.)
IF…“Pokies” on top (you see dots of bobbin thread on the quilt top)
THEN…Loosen top tension (or tighten bobbin)
IF…“Pokies” on bottom (you see dots of top thread on the quilt back)
THEN…Tighten top tension (or loosen bobbin)
IF…Railroad tracks on top (stitch lays flat and is undefined)
THEN… Loosen top tension (or tighten bobbin)
IF…Railroad tracks on bottom
THEN…Tighten top tension (or loosen bobbin)