Why are my sewing machine stitches slanted?

Happy New Year Everyone! I hope 2017 brings you health, happiness, and everything else your heart desires.

Today we are going to discuss a topic that comes up often. People with embroidery machines never ask me this question. But seamstresses will sometimes ask and quilters will often ask why their sewing machine is giving them a slanted stitch? Here is what they are asking about.

They are wondering why their “straight stitch” is slanted instead of straight. They all assume the machine is out of adjustment, but that is not why the stitches are slanted. Here are the two basic types of sewing machines.

The machine on the left (Bernina 630) has an oscillating hook. The machine on the right (Bernina 185) has a rotating hook. Machines with drop in bobbins are also rotary hook machines. Over time we will be discussing each hook type in depth, but for today I just want you to understand that it makes no difference what type of machine you have it will still sew a slanted stitch.

Here is why, the way a stitch is made. When you look at your sewing machine needle, you will notice the front has a groove and the back has a small notch above the eye of the needle. So when the needle penetrates the fabric, the thread slides in the groove. When the needle starts to rise, the thread will still slide in the groove, but since there is no groove on the back, the thread drags on the fabric and this creates a small loop. The hook picks up this loop and carries the thread past the bottom of the hook path where the thread is no longer held by the hook.



You can see the hook tips above are just past the bottom of their cycle. The thread loop they picked up from the back of the needle (the green thread) is dragged across the face of the bobbin case. In the position you see above, the thread is released from the hook and the take up lever pulls the thread up. This wraps the top thread around the bobbin thread creating a knot, or stitch.

So why are the stitches slanted? Because, the hook picked up the thread on one side of the needle and released it on the other side of the needle. So the thread enters the hole made by the needle on the side of the bobbin thread where it was picked up and leaves the hole on the other side of the needle and bobbin thread.  The bigger the needle, the more obvious this will be to the naked eye.

The arrows show the direction of sewing. The top pink stitches were made with a size 75/11 needle. The middle two purple stitches were made with a size 80/12 needle. The bottom two brown were made with a size 90/14 needle. We will discuss the different needle types and sizes in the future, but for now I just want you to be able to observe that as the needle size grows, the slant of the stitch becomes more obvious. That is because the needle is making a bigger hole in the fabric so it is easier to see which side of the hole the thread went in and which side of the hole the thread comes out.

This “straight” stitch will become much straighter when the fabric is washed. But when you are observing that straight stitches are actually slanted, there is nothing wrong with your machine…. or you. So don’t stress out over slanted stitches. Just shows your sewing machine and your quilting or seamstress work are bordering on perfect!

I try to write this blog to address questions and problems I see over and over. I hope this article was helpful. Please feel free to leave me a comment or question. The comment link is at the left of the top of this article. Again, Happy New Year! 🙂

May Your Thread Never Break!

Michael Roussin