Anatomy of a Sewing Machine Needle
At a glance, sewing machine needles all look alike. It’s hard to tell the differences on something so small. There are a lot of different types of needles out there, but don’t be intimidated. We have guides to help you master needles. You'll learn the parts of a sewing machine needle and what they do in this article. Then you can read our related posts about selecting a sewing machine needle (300089XHT) and how to change the needle (300093XHT). With the perfect needle for every project, your sewing will look better than ever before.
Have you ever wondered what makes a needle fit in one sewing machine and not in another? Or why you drop stitches when the needle isn’t right? These both have to do with the construction of the needles themselves. By knowing how the needle is set up and how it works, you can make better needle selections without any trial and error.
Anatomy of a Sewing Machine Needle
Butt: This is the top end of the needle that is inserted into the machine. The butt features a beveled end to allow for easy insertion into the needle bar.
Shank: The shank is also inserted into the machine. The needle shank must be the right shape for your machine. Needles for home sewing machines often have a shank with one flat side and one rounded side for proper positioning. Commercial or industrial needles can have grooved, threaded or round shanks.
Shoulder: This is the slope between the shank and the shaft or blade. Some needle brands will add a color-coding to the shoulder to distinguish the types and sizes of needles.
Blade: Sometimes also known as the shaft, this is the body of the needle below the shank. The size of the needle is determined by the diameter of the blade.
Groove: This is the slit above the eye and it is the part that reduces friction and creates smooth stitches. The groove cradles the thread and guides it to the eye. The length and width of the groove varies between needle sizes.
Scarf: The scarf is the indentation above the eye that allows the thread to be grabbed by the bobbin hook under the throat plate to create a stitch. A long scarf helps to eliminate skipped stitches by allowing the hook to more easily loop the thread. A shorter scarf requires a well-timed machine. The size of the scarf varies with different needle types.
Eye: The hole at the end of the needle. This is where the thread passes through. The size and shape of the eye is different on varying needle types.
Point and Tip: These parts are the very base of the needle. The point and tip vary with different needle types. Different shapes of points and sharpness of tips are used to sew through various materials. For example, a sharper point is needed to punch through leather, while a blunt tip is better for stretchy materials.
How a Stitch Is Made
All of these tiny parts on the needle work together with the machine to form a stitch. Here’s how the magic happens.
First the needle penetrates the fabric and descends to its lowest position, carrying the thread down with it. On the upstroke, the needle pushes a loop of thread out on the scarf side. This happens because the groove on the opposite side of the needle allows the thread to slip, but the thread has nowhere to go, so it gets pinched between the needle and the fabric. As the needle travels upward this “pinching” creates a loop for the hook of the bobbin shuttle to grab. As the shuttle rotates, it pulls the loop of the top thread completely around the thread from the bobbin. When the needle is pulled out of the fabric the thread is pulled up and the stitch is completed.
Understanding the parts of the needle and how they work together is the basis for making a good needle choice for each project.