In the world of thread, higher numbers mean thinner thread. So 80 wt. is thinner than 50 wt. (which is the most common sewing thread).
Such a thin thread is perfect for a variety of techniques, including English Paper Piecing, Hand Applique, Machine Embroidery, Machine Applique, Free Motion Quilting, Free Motion Couching, and more.
50wt Aurifil thread can be used for machine piecing, hand piecing, machine applique, hand needle turned applique, fine needlework, foundation piecing, miniature patchwork, detailed quilting, bobbin lace making, and machine embroidery.
When discussing weight of thread, the smaller the number, the thicker the thread. The weight is determined by how many meters of thread it takes for a skein to weigh one kilogram. In this case, the 40 wt thread is slightly thicker (heavier) than the 50 wt thread.
A 30 weight thread is heavier than a 50 weight because it is denser and takes only 30 kilometers to equal one kilogram compared to 50. – The fraction on the thread spool tells you the weight and the number of plies or strands twisted together (for instance, 60/2 is 60 weight thread with 2 plies).
Medium Weight Threads
These are the types of threads that you will most frequently find, most often 40 or 50wt. They can be used for most construction, quilting, machine embroidery, sergers, and general purpose sewing.
The best way to determine if the weight of thread is right for your project is to run the thread through your fingers to feel the thickness or thinness of the thread. Needles are sized ranging from 60/8 to 100/16 (for most quilting and thread painting use).
This 90-weight white bobbin thread is gauged specifically for Brother embroidery machines and perfectly balances the needle thread. Made of strong, durable 100-percent polyester that won't shrink, break, or fray, it makes a great, economical all-around staple.
It is helpful to remember that a 50 weight thread should be paired with a size 80/12 needle. (80 is the European size, while 12 is the American needle numbering system.)
40wt is a thread that is significantly heavier than 60wt, and noticeably heavier than the 50wt. While it is always good to have different size threads on hand, just in case, I don't usually sew on heavy fabrics, but I do consider the 40wt thread essential for my sewing stash.
Usually made of synthetic materials and engineered to withstand high stress and tension, heavy-duty thread is best for sewing thick materials like denim, canvas, and leather. With a variety of weights and finishes to choose from, the best heavyweight thread depends on the material and its intended use.
Sew-all Thread is designed to handle all demands. A fine 50 weight cotton thread but strong with a silky finish for those who prefer to sew with cotton.
Gutermann Extra Strong 12wt Polyester is a 100 percent polyester thread offers a high break point that is engineered to cope with highly stressed seams. Ideal for heavier fabrics: denim, leather, furniture, as well as for crafts.
Kevlar® thread is one of the strongest and most fire retardant commercially available threads. It is about 2.5 times stronger than nylon or polyester, has almost no stretch, does not melt, and decomposes at 800°F.
Gutermann Cotton Sewing Thread is a fine 50 weight cotton thread but strong with a silky finish for users who prefer to sew with cotton.
Your standard thread will often come in a medium 40 or 50 weight. But a huge variety of other threads exist in super fine 100 weight, or super chunky 3 weight options too.
12wt thread is actually the thickest thread you can safely fit through the eye of your machine needle and can be absolutely stunning to use in any project. These bold stitches are perfect for eye catching designs, accents, and quilting that can really change the look of your sewing.
The three most common sizes of thread in the U.S. are 30, 40, and 50 wt. (For comparison, all-purpose thread is usually 40 wt.)
Choose thread based on the type of fiber, look, feel, and thickness and not by the printed weight size. Trust your eyes and fingers more than the label. You'll get better results and be much happier with your selection. Choose fine threads to blend and medium and heavier threads to show.
Thicker thread should require more tension to avoid puckering lightweight fabrics, but this is often just what you need to avoid issues. A heavier thread in the top and bottom will increase both tensions, and you'll probably need to set a lighter tension to accommodate heavyweight fabrics.
The 60wt works fine with most all embroidery with the exception of freestanding lace (FSL). When stitching FSL, you must use the same thread in bobbin that you're stitching with on top. For fine, heirloom stitching, the 90wt. may be a better choice.
While stitching thick fabric, such as denim or leather, a tension of 3.5 to 4.5 is recommended. This is to sew through the fabric and maintain neatness throughout easily.
The simple answer is the lower the thread count, the lighter the sheet; the higher the thread count, the heavier the sheet.
Weight refers to a thread's thickness. While it is somewhat counter intuitive, a lower weight number means a thicker thread. This means a 30 weight thread is thicker than a 40 weight thread. The most common thread weight used for embroidery is 40 weight.
Gutermann Hand Quilting Thread is a 40 weight 3-ply natural Cotton Thread but strong with a silk-like luster for those who prefer to sew with natural fibers.