Most machines have a little wheel or dial that adjusts the tensions discs which adds or releases pressure on the needle thread. On our Pfaff 160s machines the tension dial goes from 0-9, where 3-5 is average. We keep it on setting 4 and don't run into too much trouble, but what does trouble look like?
Depending on the fabric your using, the quality of the thread and how new your needle is can also affect how the thread looks in your project but if everything else has checked out you might need to make minor adjustments to your tension.
In this post I am only talking about your sewing machine tension, not your serger. Serger issues are a whole other beast which I will address in a future blog.
Back to your lovely machine tension.
I found a great article on Craftsy about correct tension and how it looks. The top photo is how the stitches look from the top, the bottom photo is how the stitches look from the bottom. The article also shows serger photos is your are curious.
When adjusting tension you should only need to make small adjustments. If you feel like you are having to move your tension dial multiple numbers up or down you should change your needle and rethread your machine. If that doesn't take care of it you might be in need of a service.
Needles should be changed every 6 hours of sewing time and you should have your machine serviced every year:)
