Adjust The Tension On Your Sewing Machine

Troubleshooting tension problems on your sewing machine is a simple process that can save you a lot of money in repair costs. Before you adjust the tension on your sewing machine, always follow these simple steps:

1. Change your needle!
2. Get your instruction manual and check the threading of the upper tension.  Raise the presser foot and, using canned air, blow out any lint or dirt from between the tension discs.
3. Remove the bobbin case and check to make sure that the bobbin thread is in the bobbin case tension.
4. Test the machine on a scrap piece of fabric.  If you still have tension problems, continue with the steps listed below.

Loose Upper Tension

Figure 1 shows loops on the bottom side of the fabric.  The most common cause of this is loose needle thread tension.  However, if the bobbin thread tension is too tight the needle thread will be unable to pull the bobbin thread to the center of the fabric, causing loops on the bottom of the fabric.  While this is not common, a bent or overfilled bobbin can cause this problem.

The most common solution to eliminate loops on the bottom of the fabric is to adjust the tension of the upper thread.  Tighten the needle thread (upper) tension by turning the dial clockwise to a higher number.  Take note of the number the upper tension was set on before adjusting it.  Increase the upper tension one number at a time, testing each setting on a scrap piece of fabric until the loops are gone (Figure 3).

Tight Upper Tension

Figure 2 shows the condition of loops on the top side of the fabric.  There are two common causes of this problem.  If the upper tension is too tight, the bobbin thread will be unable to pull the top thread to the center of the fabric, causing loops on the top.

If the bobbin thread has slipped out of the bobbin case tension spring, you will have loops on the top of the fabric.

To correct this problem, first remove the bobbin case and make sure the bobbin thread is threaded through the bobbin tension spring.  If the bobbin case is threaded correctly, place it back in the machine and loosen the upper tension by turning the tension dial counter-clockwise to a lower number.  Make small adjustments while test sewing on a scrap piece of fabric until the loops disappear.

Balanced Upper And Lower Tensions

This is what we are looking for!  The needle thread and the bobbin thread are joined in the center of the fabric.  There are no visible loops on the top or bottom side of the fabric.  This stitch produces the strongest seam.