The Ultimate Thread Guide

Download the Thread Selection Chart here.

Visit Superior Threads to shop a wide variety of quality threads, and see more information about choosing threads, like the helpful information below.

The weight or size of thread is an important consideration for any sewing project. Making proper adjustments relative to different thread weights will make sewing, quilting, or embroidery projects more enjoyable.

A smaller weight number indicates a heavier thread. The weight of a thread is actually a length measurement. Dividing the length of thread by a set weight gives you the exact measurement of a thread weight.

Example: If a thread is labeled 40 wt. then 40 kilometers of that thread weigh 1 kilogram. A 30 wt. thread is heavier because it takes only 30 kilometers of thread to weigh one kilogram.

The weight of thread influences several aspects of a quilt or embroidery design, such as stitch density, needle size, and tension.

Needle size:

A general rule is to use a needle whose eye is 40% larger than the diameter of the thread. If you use a 75/11 or 80/12 size needle for 50-weight thread, you should use a needle with a larger eye when sewing with a heavier thread. We recommend a size 90/14 when sewing with a 40 wt. thread and a 100/16 needle when sewing with a 30 wt. or 12 wt. thread. If you find your thread to be shredding or skipping stitches, try a new needle and go up one size.

Tension:

Thread tension on most sewing machines is accomplished by applying pressure to one side of a spring that presses on a tension disk. Tension is applied to the thread as it passes between a pair of tension disks. Tension may be adjusted mechanically by means of a thumb wheel, or electronically through a computer-controlled electromagnet. Increased pressure on the tension spring increases thread tension. When a 40 wt. thread is replaced by a heavier 30 wt. thread, the increased diameter pushes the tension disks further apart, increasing pressure on the tension spring. Just by increasing (or decreasing) the diameter of our thread, we have increased or decreased the thread tension. If the tension is too high, it damages the thread and the thread can break. If it is too low, the thread will loop on the back of the fabric. When you change threads, remember to take the diameter of the new thread into consideration and make adjustments as necessary.

For embroidery:

Most digitized designs are created for 40-weight thread, which ensures adequate coverage for embroidery. If a 30-weight thread is used, the increased diameter of the thread can present a lumpy appearance or cause the thread to bind on itself which will break the thread or jam the machine. To correct this, reduce the density by one-third or increase the design size by 125% of the original. Increasing the stitch length will also help.

Cotton: Cotton threads are made from twisting the fine staples (fibers) from a cotton bowl to create a thread. There are many degrees of cotton quality. Superior's cotton threads are made from Egyptian-grown extra-long-staple cotton fibers.

Advantages: Its strength, medium sheen, and natural fibers help grab the fabric to create a tight seam.

Disadvantages: Difficult to tell low-quality from high-quality, low-to-high lint depending on the staple length and processing, and quality cotton threads can be more expensive.

Polyester: Polyester threads are a popular choice for many sewing applications. Its versatility is unmatched and can be made to look and feel like different fiber types, such as cotton and silk. Superior has a wide selection of polyester threads from a fine monofilament thread for invisible stitching to thick, decorative corespun threads for bold top-stitching.

Rayon: Rayon is created by pressing cellulose acetate (usually made from wood pulp) through small holes and solidifying it in the form of filaments.

Advantages: Its high-sheen colors, soft touch, and it's an inexpensive thread.

Disadvantages: It's often not colorfast (the dye can bleed onto fabric when exposed to strong detergent, UV light, or bleach), and it's not as strong as polyester.

Nylon: Nylon threads are synthetic threads (polyester threads are synthetic as well) often used in the form of a monofilament clear thread or as a textured fuzzy (woollie-like) thread. The negatives far outweigh the positives of nylon. We do not recommend sewing or quilting with nylon threads, as there are better versions for the same application in polyester threads.

Metallic: Metallic threads are created from multiple layers of materials wrapped and twisted together. The quality of metallic threads range from very high to very low. A good metallic thread does not require a lubricant. Superior's metallic threads have a strong nylon core, a thin layer of rice paper and a special outer coating that keeps the silver foil from rubbing against the needle.

Advantages: Beautiful sheen and excellent stitch quality when embroidered, quilted, or sewn.

Disadvantages: Tension adjustments are required and stitching speed may need to be decreased.

All sewing and quilting thread undergo some of the same processing, such as twisting, lubricating, winding, etc. Cotton threads however, can have additional processing to enhance the stitching experience.

Mercerized: Mercerization is the process of immersing the cotton fibers in a caustic solution which causes the fibers to swell. This allows the dye to better penetrate the fibers and increases the luster of the thread. Mercerizing also increases the strength of the cotton thread. Nearly all cotton threads made for sewing all mercerized, whether the label states Mercerized or not.

Gassed: Thread that has been gassed is smoother, has lower lint, and a brighter sheen. The thread is passed through a flame at high speed to burn off the longest pieces of lint, resulting in a less fuzzy thread. Gassing is also called silk finish or polished cotton.

Glazed or Coated: Glazed thread is treated with a coat of wax, resin, or starch and then polished to create a nice luster. The thread is very strong due to the glaze and is recommended for hand quilting. Glazed cotton threads are not recommended for machine sewing or machine quilting because the coating can rub off in the tension discs and collect lint, fuzz, dust, and cause a buildup to obstruct the thread path.