Adjusting Bobbin Tension
(Achieving Perfectly Balanced Stitches)
@Paigehandmade
@SEMNsewinmachines
@Howcast
Step-by-Step Instructions:
Perfect stitches require the top thread and bobbin thread to lock exactly in the middle of the fabric layers. Adjusting bobbin tension can seem scary, but it is often the secret to flawless stitching.
Materials Needed:
- Bobbin and bobbin case
- Small flathead screwdriver
- Two contrasting thread colors
- Scrap fabric (same as your project)
- Lint brush
Tips for Success:
- Always check and adjust your top thread tension before messing with the bobbin!
- Clean out any lint under the bobbin tension spring; sometimes, a tiny piece of fuzz is the only problem.
- Remember: “Lefty loosey, righty tighty.”
1. The “Drop Test” (For Front-Loading Bobbins)
- Place a full bobbin into the removable metal case and pull the thread through the tension spring. Hold the thread tail and let the bobbin case dangle. Give it a gentle yo-yo bounce. It should drop an inch or two and stop. If it free-falls, it’s too loose. If it doesn’t move at all, it’s too tight.
2. Locate the Tension Screw
- Look at the side of the metal bobbin case (or the drop-in casing, if your machine allows adjustments). There is usually a larger screw that holds the tension spring. This is the screw you will adjust. (Do not touch the smaller screw next to it, if there is one).
3. Adjust in Micro-Increments
- Using your small screwdriver, turn the screw in tiny increments—think of it as adjusting the time on a clock by only 5 or 10 “minutes” at a time. Turn left (counter-clockwise) to loosen, or right (clockwise) to tighten.
4. Retest the Tension
- Perform the drop test again to see if the tension has improved. Repeat the micro-adjustments until the bobbin drops just a little bit with a gentle bounce.
5. Test Sew on Scrap Fabric
- Thread your machine with a different color on top than in the bobbin. Sew a straight line on a scrap of fabric. If you see bobbin thread on top, the bobbin tension is too loose (or top is too tight). If you see top thread on the bottom, the bobbin tension is too tight (or top is too loose). Adjust until the threads lock perfectly in the center.
Top FAQs for Bobbin Tension:
Should I adjust the top or bobbin tension first? +
Always adjust your top tension first! About 90% of all tension problems can be solved simply by adjusting the top tension dial or re-threading the machine with the presser foot up. Only touch the bobbin tension if top adjustments completely fail.
Can I adjust a top-loading (drop-in) bobbin? +
Yes, most top-loading drop-in bobbins have a tension screw on the casing, but you usually have to remove the metal needle plate to access it. Check your specific machine’s manual, as these casings are often plastic and very sensitive to adjustments.
Why did my bobbin tension suddenly get worse? +
Sudden tension issues are almost always caused by lint or a stray piece of thread caught under the bobbin tension spring. Before turning any screws, take a pin or a stiff brush and clean out the slot under the flat spring on the bobbin case to restore smooth thread flow.
