Stitch and Stitch length A Stitch is the pressing of a thread through a hole made by the needle into layers of material (leather, wool, vinyl, or other fabrics) and the thread is looped onto the thread in the bobbin and pulled up to make the next stitch. The Stitch Length is the distance (usually in millimeters) from one stitch to the next. The Stitch Length is usually fixed for a given sewing task. Shorter stitch lengths are used to join material together and a longer length is preferred for top stitching when it is likely to be seen.
Attachments Many attachments are available to help make your job easier. Several different presser foot options are available for certain tasks. They include folders and special feet such as a welt foot or sometimes called a piping foot. A welt foot is one that has rounded edges on the bottom to make piping or welt assemblies. They come in a variety of sizes depending on the diameter of the desired piping. Welt Foot attachments usually come with their own Needle Foot as they are manufactured with close tolerance to each other. When changing a Presser Foot to a Welt Foot, change over all the components. They are manufactured as matched sets and should always be kept together. Other Presser Foot attachments include one for zippers, seams, and others.
Be sure to check out specialty catalogs to become familiar with the many attachments that are available for your machine.
Regular presser foot This is the most common sewing machine where the presser foot stays down all the time and the needle operates straight up and down and the Feed Dog drops below the shuttle cover and rises to pull the material backward the distance of one stitch length. The regular presser foot machine can tackle light weight fabrics. When the fabrics begin to get to heavy, the Feed Dog doesn't pull the material all the way and the stitch length is compromised, often causing the thread to bunch up.
Walking needle This is not as common as the other type sewing machines. The presser foot stays down and the needle operates up and down and in a front to back oval motion. It is timed with the Feed Dog to pull the material backward the distance of one stitch length. The walking needle machine uses the needle's lateral force to help pull the material through the stitch length. This is an improvement over the regular presser foot machine, but again can bunch up the thread if the material doesn't move all the way of the stitch length.
Walking Foot (sometimes called a Compound Walking Foot). This is more common in the commercial upholstery trade as its capabilities can handle the thick materials frequently found when sewing multiple layers. The walking foot machine moves 1) the Feed Dog and 2) the Presser Foot up and down, 3) the Needle Foot and 4) the needle itself in a front to back oval motion in time with the motion of the Feed Dog. The intent of the walking foot is to raise the Presser Foot to relieve pressure of the material against the Shuttle cover plate and allow the Needle Foot to come down and grab the material from above and from below via the Feed Dog and make a single stitch all in time. Using all four components (Presser Foot, Needle Foot, Feed Dog and Needle), the walking foot machine can sew stitches in the thickest of materials, like four to six layers of leather, heavy canvas (like sail boat sails), and in some cases even sew through cardboard.
In Part 2 of our Upholstery Series, we cover basic stitches and techniques.
The Hog Ring and the Hog Ring Discussion Forum, a generic resource specifically for auto upholstery
Toledo Industrial Sewing Machine, sales and service of machines including valuable references
Superior Threads offers a wide variety of different types of upholstery threads and needle supplies including valuable references and an education section
American Trim and Upholstery Supply
Gilbreath Upholstery Supply
McMaster-Carr Industrial Supplier (For pulleys and belts)
Grainger Industrial Supply (For pulleys and belts)
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