Bobbin Tension Troubles

🧵 Why Does My Bobbin Keep Unwinding and Jamming? [Embroidery Troubleshooting]

If you're constantly battling with your bobbin unwinding, snagging, and jamming your embroidery machine — you're not alone. This frustrating issue happens more often than you'd think, especially if you're winding your own bobbins. Let's walk through a real-life scenario and what might be going wrong.

📸 What's Going On in the Photos?

The user shared photos of a metal bobbin in a bobbin case, showing how the thread appears loose and easily snags. The issue happens every time a new full bobbin is inserted: it begins to unwind by itself before the thread even reaches the tension ear, causing a jam mid-stitch.

🛠️ What's Likely the Problem?

Incorrect bobbin tension is usually the culprit. Here's why:

1. Tension Was Too High

The user measured their bobbin tension and found it to be 30–40 grams, while the correct range should be around 20 grams for embroidery. This means the thread wasn’t being held back properly and could easily spill out or cause backlash.

2. Winding Your Own Bobbins?

Many people prefer to wind their own bobbins using an electric bobbin winder. However, these winders need to be specific to embroidery bobbins, not general sewing machines. Uneven winding causes the thread to build up irregularly, leading to imbalance and loosening mid-use.

3. Metal vs. Cardboard Bobbins

Someone noted a key point: cardboard-sided bobbins can be problematic. If there’s an imperfection in the cardboard, it can unbalance the bobbin, making it wobble in the bobbin case. Metal bobbins — like the one shown in the images — are preferred for better consistency, as long as they’re properly wound and tensioned.

🧪 Quick Tension Test

When the bobbin is threaded and you pull the thread to the right, the bobbin should spin to the left. (Looking at the front of the case)

If that doesn’t happen, the bobbin may be inserted incorrectly or wound with too little or too much tension.

✅ What You Can Do

✔ Use a Bobbin Tension Gauge

These small tools help you measure exact pull weight. Ideal bobbin tension for embroidery:
18–22 grams of force (gf).
Your reading of 30–40 gf was way off!

✔ Choose Prewound Magnetic Bobbins

Many professionals recommend prewound magnetic bobbins — they eliminate winding error, reduce vibration, and help keep tension steady.

✔ Clean the Bobbin Case

Lint buildup or even a tiny thread caught under the tension spring can affect how the bobbin behaves.

✔ Rewind Sloppy Bobbins

If your bobbin looks uneven, has loose loops, or is puffing out from the sides, rewind it using the correct tension settings or switch to a better winder.

🎥 Want to See It in Action?

You might want to check out this YouTube video (link placeholder — please replace it with your video if you have the exact one). It goes deep into bobbin tension testing, winding tips, and how to fix these exact issues.

🧵 Final Thoughts

If your embroidery machine jams and the bobbin thread is out of control — start with the tension. Measure it, clean the case, use the right materials, and consider upgrading to magnetic prewounds for peace of mind.

Happy stitching! ✨
Have a similar problem or tip? Drop it in the comments below! 💬