At first glance, the plethora of needle types may seem confusing, but it won’t be once you understand what makes them different and how they work. Two important factors that affect a machine needle’s suitability for a specific need are its basic anatomy and size.

The Needle

As shown in the diagram above, the upper part of the needle is the shank and the lower part is the shaft. The shank is rounded on the needle front and flat on the back. Insert the needle into the machine clamp with the front (rounded part) facing you.

The shaft consists of a groove on the front that guides the thread and an indented scarf on the back that enables the bobbin case hook to get close to the eye of the needle. Its other two elements, the eye and the point, are key factors that vary and affect the needle’s performance with different threads and fabrics.

Needle Sizes
Most needle packages are marked with both European and American numbering systems, such as 70/10 or 80/12, and the needle itself is usually marked with one or both numbers. Some needle manufacturers also color code the upper part of the needle shaft for easy identification. Sizes range from the finest 60/8 needles to the heaviest 120/19 needles, and available sizes vary within the different types.

The best needle size to use depends on the fabric type you’re stitching. Finely woven fabrics require a small needle so it will not make holes in the fabric; a larger needle is necessary to stitch heavy or coarse fabrics. A rule of thumb: The larger the number, the stronger the needle.