Several standards are used to describe thread size, so it can be confusing! Thread size is determined by dividing the length of thread by its weight. The term “Tex” refers to the weight in grams of 1,000 meters of thread. The higher the Tex rating, the thicker the thread. Tex 70 is the heaviest size that is recommended for standard home sewing machines. The size of the thread determines the needle that should be used. As a general rule, the eye of the needle should be about 60% larger than the thread.

To learn more, see WAWAK’s Sewing Thread Size Conversion Chart.

If you prefer to purchase large cones of thread, but your sewing machine isn’t equipped to use them, you can purchase a separate cone thread holder. Some people use a modified bobbin winder to refill smaller spools from a large cone of thread. (Remember to save your empty spools.) However, that’s a subject for another article!