Sewing machine tension is a crucial factor that determines the quality of your stitches. Proper tension ensures that the top and bottom threads interlock correctly, resulting in neat and balanced stitches. Whether you’re a beginner or an experienced seamstress, understanding how to adjust tension on a sewing machine is essential for achieving professional-looking results. In this guide, we’ll walk you through the steps to adjust tension on your sewing machine.

Understanding Sewing Machine Tension

Before you start adjusting the tension, it’s essential to grasp the concept of sewing machine tension. Sewing machines have two types of tension: upper thread tension and bobbin thread tension. The balance between these two tensions ensures that the threads form evenly spaced and secure stitches.

Upper Thread Tension: This tension is controlled by a dial or knob on the sewing machine’s front or top. Increasing the upper thread tension tightens the thread, while decreasing it loosens the thread.
Bobbin Thread Tension: Bobbin thread tension is less commonly adjusted, and it’s usually set by the manufacturer. It can be altered by adjusting a small screw on the bobbin case. In most cases, it’s best to leave the bobbin thread tension as is and focus on adjusting the upper thread tension.

Steps to Adjust Sewing Machine Tension

Select the Right Thread and Needle:
- Ensure that you’re using the appropriate thread weight for your fabric. Lighter fabrics may require finer threads, while heavier fabrics need thicker threads.
- Match the needle size to the fabric and thread. A needle that’s too small can cause tension issues.
Thread the Machine Correctly:
- Follow the threading instructions in your sewing machine manual carefully. Incorrect threading can lead to tension problems.
Set the Upper Thread Tension:
- Begin with the upper thread tension dial or knob set to the default or “auto” position (usually indicated by a circle).
- Test sew a few stitches on a scrap piece of fabric. Examine the stitches to determine if they are balanced. Balanced stitches have the top and bottom threads meeting in the middle of the fabric.
- If the stitches are not balanced, you’ll need to adjust the upper thread tension.
- To increase tension (tighten the upper thread), turn the tension dial slightly to a higher number. To decrease tension (loosen the upper thread), turn the dial to a lower number.
- Make small adjustments, testing after each one until you achieve balanced stitches.
Check Bobbin Thread Tension (if necessary):
- Only adjust the bobbin thread tension as a last resort. Most tension issues can be resolved by adjusting the upper thread tension.
- If you decide to adjust the bobbin tension, consult your sewing machine’s manual for specific instructions, as it varies between machines.
Test and Fine-Tune:
- Continue to test your stitches on scrap fabric until you achieve the desired results.
- Pay attention to different fabric types and thicknesses, as tension adjustments may be needed for each.
Document Your Settings:
- Once you find the correct tension setting for a particular fabric and thread combination, consider jotting it down in your sewing journal or machine manual. This way, you can easily reference it for future projects.
Regular Maintenance:
- Keep your sewing machine clean and well-maintained. Regularly clean lint and debris from the tension disks and bobbin area to prevent tension problems.

Troubleshooting Tension Issues

Sometimes, despite your best efforts, you may still encounter tension problems while sewing. Here are some common issues and their solutions:

Thread Breakage:
- If your thread keeps breaking, it may be due to excessive tension. Try reducing the upper thread tension slightly.
- Ensure that the needle and thread are suitable for the fabric you’re sewing.
Loopy Stitches on Top or Bottom:
- If you’re getting loopy stitches on the top of your fabric, your upper thread tension may be too loose. Tighten it incrementally.
- If you’re getting loopy stitches on the bottom (bobbin thread showing on top), your upper thread tension may be too tight. Loosen it gradually.
- Check that the bobbin is correctly threaded and placed in the bobbin case.
Uneven Stitches:
- Uneven stitches can result from an uneven feed, so make sure the fabric is evenly guided through the machine.
- Ensure that the presser foot is down when sewing, as sewing with it up can disrupt tension.
Skipped Stitches:
- Skipped stitches may be caused by a dull or damaged needle. Replace the needle with a new, appropriate one for your project.
- Ensure the needle is inserted correctly and fully into the machine.
Puckering Fabric:
- Puckering can occur if the upper thread tension is too tight for the fabric. Try reducing the tension slightly.
- Use the appropriate stitch length and presser foot pressure for your fabric type.
Fabric Not Feeding Smoothly:
- If the fabric isn’t moving smoothly, the presser foot pressure may be too high or too low. Adjust it according to your machine’s settings.
Thread Nesting Under the Fabric:
- If you see a tangled mess of thread under your fabric, it’s likely due to incorrect threading, bobbin issues, or a lack of tension. Re-thread the machine, check the bobbin, and adjust the upper thread tension as needed.
Inconsistent Tension on Different Fabrics:
- Some fabrics may require more significant tension adjustments than others. It’s common to fine-tune tension settings when switching between fabric types.

Remember that sewing machine tension adjustments can be a bit trial-and-error, but with practice, you’ll become more adept at diagnosing and solving tension-related issues. Always refer to your sewing machine’s manual for specific instructions related to your model.

Adjusting Bobbin Tension

Step	Procedure	Tools Needed	Common Issues	Solutions
1	Turn off the sewing machine	None	Uneven stitches	Check bobbin for lint, debris
2	Remove the bobbin case	Screwdriver	Thread bunching	Adjust bobbin tension screw
3	Adjust the tension screw	Screwdriver	Skipped stitches	Turn clockwise for tighter tension
4	Reinsert the bobbin case	None	Thread breakage	Turn counterclockwise for looser tension
5	Test with scrap fabric	Fabric scrap		Fine-tune as needed

Adjusting Upper Thread Tension

Step	Procedure	Tools Needed	Common Issues	Solutions
1	Set tension to default	Sewing machine	Thread loops	Check upper threading
2	Thread the machine properly	Thread spool, bobbin	Thread too tight	Adjust tension dial lower for looser tension
3	Sew a test seam	Fabric scrap	Thread too loose	Adjust tension dial higher for tighter tension
4	Observe stitch quality		Skipped stitches	Test with different fabrics
5	Make necessary adjustments			Until stitches are even