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Bobbin Tension | How to Adjust and why it's Important

Posted: 18 October 2012 at 9:43 a.m.

We talk a lot about tension settings and tension adjustments on machines.  90% of the time, we adjust the top tension to achieve the perfect stitch. This time, we will discuss the other 10%, the bobbin tension. Many have been told to never touch the bobbin tension. It isn't as difficult as we have been led to believe. If you are one who has been told to never touch it, by the end of this page, hopefully you will realize that is perfectly safe and easy to adjust the bobbin case. Of course you could buy a second bobbin case, one to never adjust and the other to experiment with, but why not save $30 to $40 and learn how easy and safe it really is. Over time, tensions can change with regular use. Even though you haven't physically changed the settings, they can work themselves either tighter or looser. Thread, lint, and even temperature can affect them. There are three times when adjusting the bobbin tension might be necessary. Number one and two are obvious. Number three is the "I never thought of that before" alternative.

  1. When using a very smooth, fine bobbin thread. If the thread is very smooth and fine, the preset setting may not apply the necessary brakes to stop it when you stop sewing. In this case, the bobbin thread continues to unwind, potentially causing backlash, and upon start up again, the thread will break. Tightening the tension will fix this.  
  2. When using a very heavy bobbin thread. The preset tension might be too tight for a heavy thread, preventing the bobbin thread from unwinding freely. Loosening the bobbin tension will solve this. (Be sure to turn the tension screw in small increments whether you are tightening or loosening the screw.)
  3. There are times when the bobbin adjustment is correct but no matter what I do to the top tension, I still can't get a perfect stitch or the thread breaks. When I loosen the top tension adequately low to run a sensitive or heavier thread, I get loops on the back. When I tighten up the top tension to get rid of the looping, the thread breaks. Looping on the back means the top tension is too loose compared to the bobbin tension so the bobbin thread is pulling too much top thread underneath. By tightening the top tension, the loops will stop, but the added tension may cause breakage, especially with sensitive threads. 

(In this case, it might be necessary to loosen both the bobbin tension AND the upper tension. By loosening both the top and bobbin tensions, both sides of the tug-of-war give in, allowing a good stitch without breaking or looping.)

Bobbin Tension Diagram by Superior Threads. How to adjust your bobbin tension.


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  • 8. Todd (13 December 2012 at 5:10 p.m.)

    @Marnie - Color conversion charts are never exact. We choose our colors from a pallet of 1,600 colors so there are 200 blues, 200 reds, 200 greens, etc. to choose from. Different brands do not choose the exact shades and therefore trying to come up with a comparison is impractical. We do have TCH & TXT files available for Magnifico which you can download onto your embroidery machine to give you the color swatch preview of the threads. Please click on 'Reference Guides' and you will see the option there. We also have Magnifico to Pantone comparisons.
  • 7. Marnie (12 December 2012 at 8:23 a.m.)

    Is there a place where one can go to get color conversions from one manufacturer to another. I would like to use the Magnifico for embroidery, but when the pattern calls for a certain color, it would be nice to see what ST recommends in its stead.
  • 6. Gail (21 October 2012 at 2:01 p.m.)

    I'm with Joyce...A tutorial about how to adjust the top tension would be very helpful... Thanks
  • 5. Michele Shea (18 October 2012 at 3:35 p.m.)

    Please include information on the adjustment of the bobbin case in the drop in bobbins like so many machine have no now days. Thank you! m:)
  • 4. Cheryl Prinsenberg (18 October 2012 at 2:16 p.m.)

    Thank you on how to fix looping on back. Tightening top tension helped alot but wasn't the perfect fix.
  • 3. Jana (18 October 2012 at 11:07 a.m.)

    I recommend when loosening the bobbin tension to do so with the bobbin inside a plastic bag (i.e. gallon zipper bag). This way, if you accidentally loosen it too much and the bobbin flies apart, all those flying parts are contained inside the bag instead of to the four corners of the room.
  • 2. Todd (18 October 2012 at 10:16 a.m.)

    @Joyce - We have several articles on tension adjustment. Please click on the 'Education' tab at the top, select 'Articles', then select 'Tension'. We also some informative videos on Tension. This video is a good place to start
  • 1. Joyce Triezenberg (18 October 2012 at 10:12 a.m.)

    If 90% of the adjustments need to be made to the top tension, how about a tutorial on how to do this?

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