How to adjust the tension on a drop-in bobbin case.

Luckily, needing to adjust the bobbin tension is not too common, unless you use significantly different weight threads, or have a multi-needle embroidery machine, and use both plastic and metal bobbins.

If you have changed the needle, checked our thread, and checked the upper threading and checked your bobbin is in the correct way and the bobbin thread is going through the bobbin case tension guides on your home sewing machine, now it's time to adjust the tension on you bobbin case. Of course if you are not comfortable making this adjustment please schedule a Quick Clean with me at TC's Sew Loved Machine Care. or with your local independent sewing machine service provider.

The pictures shown are from a Singer Stylist 7258, so your machine and bobbin case will be a little different.

Depending on your machine, you may need to remove the needle plate and remove the bobbin case to make any adjustments. Some machines you can adjust the bobbin tension, by just removing the bobbin cover and lifting the bobbin case up slightly, just enough to get to the adjustment screw with a precision screwdriver.

On the Singer Stylist 7258. they were nice enough to have an access point to make adjustments to the bobbin case. I'm including pictures of the bobbin case to show which screw is for tension adjustments.

                          

Just like any screw it's "Righty-Tighty; Lefty-Loosey.

When adjusting the bobbin tension, make tiny adjustments, no more than a quarter turn in either direction. Then do a test stitch using a mid-length and mid-width zig-zag stitch.

If your upper tension is set to the appropriate upper tension for your machine, and the upper threads are showing on the underside of your fabric,

• Adjust the bobbin tension the the left one-quarter turn, 
  • To loosen the bobbin tension.
  • Do a test stitch.

If your bobbin thread is showing on the top of your fabric

• Adjust the bobbin tension to the right, one-quarter turn
  • To tighten the bobbin tension. 
  • Do a test stitch

Keep adjusting and doing a test stitch until the upper thread and bobbin threads match.

Additional note: If you are using stretch stitches or buttonhole stitches you may need to adjust the upper tension for them to align properly.

Some older modern machines have an adjustment knob or screw, usually on the back or below the hand wheel for adjusting the stretch stitches or buttonhole stitches.

You may also check the user manual for your specific machine for images of how balanced stitches should look, and tips for your specific machine. (Many user manuals can be fount online, if you don't have the one that came with your machine.