thread is used on lightweight garments such as shirts which are subject to little stress, but a specialty thread called buttonhole twist is used on items that experience more wear and tear, such as coats and pants. If a sewer uses regular thread, they usually use a double thread to strengthen the quality of the stitching. Long coats that are good-quality or better often have a special shank at the bottom button. Because the bottom button of a coat is subject to a lot of stress, shanks are typically longer than usual and are sometimes made with elastic-thread. In addition to the special shank, an additional (shankless) button with no thread shank is often used on the underside of the fabric when sewing the button on. As a result, the stress to the button, shank, and thread pulls on this second button instead of the fabric. This prevents the thread from damaging and ripping the fabric, and is one of two ways to prevent "popping a button" (the other method is to use good strong thread such as buttonhole twist). In addition to the typical shank and shankless buttons, covered buttons are shank buttons that have fabric completely covering the back. They are stitched on like regular shank buttons, but the sewer has to "feel" for the shank while they are sewing the button on. Covered buttons are handmade (to some degree), expensive, and are used in high-end and specialty garments. See also Button Sewing Yarn Citations References Singer Clothing Care & Repair by The Editors of Cy DeCosse Incorporated Threads magazine Issue 117 March 2005 pp.58 Textile closures Buttons