Every other bobbin: Remove lint and dust bunnies from your bobbin area and needle shaft.
Every project: Thoroughly clean and oil your machine per manufacturers guidelines.
Every 6-12 months: Have your machine serviced by a qualified technician. The techs can uncover and solve issues we may not recognize – protect your investment.
Tension
In the factory, machine tension is set to stitch through 2 layers of fabric using a 50wt, 3ply thread. With today’s advanced threads and wide variety of available weights and ply, the “default” or factory setting isn’t always the best number. If your thread is breaking or shredding, consider troubleshooting this setting by loosening your top tension. This is accomplished by selecting a lower number on your dial or digital setting.
Lowering the tension by a whole number or 2 will allow you to examine the impact on a fabric sample (use a sample that closely represents the project materials you’re using).
Once you’ve lowered the top tension run through a sample. If the thread no longer breaks or shreds but the bobbin thread is now showing on top, reduce the top tension another whole number. If the top thread is showing on the bottom side, you’ll need to step up or increase the top tension to bring it back to the top.
Tension — it’s a tug of war between the top and bottom thread. Look at the simplicity of this Tension diagram from a 1947 Singer Featherweight 221.