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Thread Tension

Understanding and setting your thread tension properly can mean the difference in high-quality good-looking embroidery and frustrating and ugly stitches.

Think of thread tension as a game of tug-of-war between the bobbin thread and the upper threads. Two groups of kids on the playground are facing off, but instead of out pulling each other they are trying to keep a knot in the middle of the rope in the center.

If Team Bobbin pulls really hard then Team Needle 1 has to pull harder to keep the knot in the center. On the other hand, if Team Bobbin is not pulling very hard then Team Needle 1 does not have to pull hard.  

The extremes are:

  • If both teams are pulling too hard you will have more thread breaks and broken needles.
  • If both teams are not pulling very hard you will have loopy thread on top and the chance of more bird nest.




Bobbin Tension:

According to the Towa Bobbin gauge information, the tension on the bobbin should be set at 170gf. I have noticed that many embroidery machines come from the manufacturer set at 300gf. I have seen embroidery machines set at 125gf that sew fine and I have also seen machines set at 600gf that sew.

The trick to setting your tension is set your bobbin once and use the H-Test to adjust your upper tension. As long as the upper tension is adjusted to your bobbin you should  be able to make some stitches.

Here are a few facts that I have found that when working with tension.

  • Thread tension is the balance ratio between the upper thread and the bobbin thread.
  • Set your bobbin thread then adjust your upper thread to the bobbin using the H-Test
  • Some machines sew better with tighter tension than others.
  • There is a range of tightness that you can set the tension at that may or may not be right for your machine.
  • Never tighten down your tension knobs as tight as they will go. You will destroy the springs tension and you will need to replace them.

When I first started working on machines, I asked a fellow technician if they had any tips on tension. He said, “You have to do whatever it takes to make it sew.”


Notes on thread: Not all thread is created equal. 

Thread is measured in thread weight. I have copied and pasted the definition of thread weight below and trying to understand it makes my head hurt.

Weights of thread: Fixed weight systems describe the length of thread needed to weigh a specific amount. In these systems, the higher the number, the finer the thread. Two systems are the Cotton count which is based on 840 hanks =1 lb and Thread weight based on 30 meters = 1 gram.

So, cutting through all the hoorah here is the skinny on Thread Weight. Thread weight refers to the diameter of the thread, the higher the number the smaller in diameter the thread. The most common size thread for commercial embroidery is 40 weight thread. Most commercial embroidery machines use thread ranging from 65 weight thread which is small in diameter to 40wt, to 30wt, to 12wt which is progressively bigger in diameter.

Here are some facts about thread and the effect on tension:

  • Some 40wt thread my not be a true 40wt. it could range in size from maybe a 36wt to a 43wt. The difference in diameter may affect your tension.

  • On some cheaper embroidery threads the diameter may fluctuate on the same spool.

  • Dust on your thread or fumes from screen printing ovens can settle on exposed thread and can affect the tension.

  • The color of the thread can affect your tension.

If you have white thread on your machine and it is dialed in perfectly, and you change it to black this could affect your tension. Black pulls through the machine easier than white. It may be the chemicals they use on white or the way it is processed.

I use the black and white as an example, but this happens with almost any thread that you change out on the machine. It is usually not enough to worry about but if you change to another color and notice a tension difference then that may be your issue.





Videos and information on Tensioning:

Madeira USA - Adjusting Thread Tensions & Bobbin Tension

The Embroidery Coach - Balanced Embroidery Thread Tension: A Must For High Production And Quality Embroidery









Tension Guages

Here is information on tension gauges that you might find useful. There are mainly two sizes of bobbins used in most embroidery machines. Class L, and Class M (Jumbo). If you order the bobbin gauges make sure your order the proper one for your machine.

Your tension gauge may be scaled in gf or N/m.

  • gf = grams-force/inch
  • N/m = newton/metre

AllStitch Embroidery Supplies: What Size Bobbins Will Work In My Home Embroidery Machine? — There are 3 different sizes of machine embroidery bobbins that we sell, style L, M, and A (also know as Class 15). These do not stand for large and medium. The L & Class 15 embroidery bobbins are the smaller bobbins, they are about the size of a nickel. L fits most commercial embroidery machines and many home machines, A, or Class 15 fit many home machines only. Style M machine embroidery bobbins are about the size of a quarter. They are also sometimes called jumbo bobbins. Your embroidery machine must have been manufactured to take the M bobbin, or they will not fit.

Click here for the home embroidery machine bobbin size chart (PDF download)







The following information is from Madeira USA




Tajima's pencil style tension gauge for setting proper top thread tensions.

The Tajima top thread pencil style tension gauge has a hook on one side with a slide guide that is used to set top thread tension on commercial embroidery machines. The slide needle works with a spring to indicate if you need to tighten or loosen top thread tension.


  • Tajima top thread tension gauge
  • Spring driven analog window
  • 5.5” long

For use with:

  • Embroidery thread on commercial embroidery machines

How to use:
To check your top thread tension, have your embroidery thread correctly threaded through your machine’s running path including through the needle and presser foot. Wrap the end of the embroidery thread around the hook end on the gauge so that it catches without slipping. Slowly and steadily pull the gauge back toward yourself. Note the common number seen on the gauge’s needle. 

Top thread tensions may vary up or down by as much as 5 to 10 gf.

  • Rayon #40: 150gf
  • Polyneon #40: 170gf
  • Metallic #40-50: 170gf
  • Polyester CR #40: 125gf
  • Burmilana #12: 190gf




TTG Tajima Thread Tension Gauge Tool 

 Photo from ALLSTITCH.com

Click on the image to see Allstitch







 Towa® L Style bobbin gauge for setting proper tension.

This Towa® bobbin tension gauge helps set proper bobbin thread tensioning. The analog spring-loaded needle measures the tension on metal bobbin cases.


  • Towa® L Style bobbin gauge
  • Spring driven analog needle
  • 4.5” x 2.5” x .75"




 TM-1 Towa Embroidery Bobbin Case Thread Tension Gauge

Photo from ALLSTITCH.com

Click on the image to see Allstitch







This Towa® digital tension gauge is used to accurately set top and bottom thread tensions.

The Towa® digital tension gauge is used to set both bobbin thread and top thread tensions. The digital feature allows you to achieve your machine’s ultimate tension setting easily and accurately. Comes with the L Style bobbin case insert. An M Style insert may be purchased separately (Item #200-M).


  • Towa® digital tension gauge
  • L Style bobbin insert
  • 5" x 2.5" x 1.25"

Obtaining your machine’s ideal thread tension will vary from machine to machine and person to person. As a guideline for starting: Set your bobbin case tension between 22gf and 25gf.

Guideline Setting Numbers for Top Thread Tensions:

  •  Rayon #40: 150gf
  • Polyneon #40: 170gf
  • Metallic #40-50: 170gf
  • Polyester CR #40: 125gf
  • Burmilana #12: 190gf

The numbers above are intended to be used as a guideline and may need to be adjusted up or down depending upon your specific machine. Be sure to set your gauge to the gf (gram force) setting by using the toggle button in the upper right corner of your gauge.





Manufacturer Manual TOWA Digital Tension Gauge.pdf

200-60-L How to Set Proper Top Thread Tension.pdf

Video tutorial on How to Use the Digital Tension Gauge: Top Thread

Video tutorial on How to Use the Digital Tension Gauge: Bottom Thread