The Feed Dogs

(or, dealing with fabric creep)

The metal "teeth" located under the presser foot are commonly referred to as "feed dogs." These guys are responsible for moving the fabric along as you sew. The longer your stitch length, the more they move.

When sewing, you place two layers of fabric under the foot. However, only the bottom layer is in contact with the feed dogs. In contrast the upper layer of fabric receives friction from contact with the immobile presser foot. Therefore the lower layer of fabric is likely to move through faster than the upper. As a result, you will often find that when you reach the end of a long seam, the bottom layer is "finished" before the top layer, which then extends on farther. This is called "creep."

There are several ways to deal with creep. Pinning adequately, perpendicularly to the seamline, is one. Still, in some instances, you may notice that the top layer of fabric forms a bubble in front of the foot, like a rat under the rug, that grows before each pin in succession.

Try holding the bottom layer of fabric firmly to allow the top layer to "catch up" as you sew. You can further encourage the top layer to feed evenly by using a pin, ripper, awl, or my favorite - a wooden shish-ka-bob stick - to stroke the top layer of fabric towards the needle, helping it to feed. These techniques become second nature with a bit of practice.

Some fabrics present especially difficult feeding problems. The biggest culprit is velvet. Velvet is usually sewn with a "walking foot" otherwise known as an "even feed foot." This is a special presser foot that actually has feed dogs underneath it. The fabric then has feed dogs on top and below, allowing it to feed evenly.

Leather, suede, and vinyl also resist even feeding. Those fabrics tend to "stick" to the underside of the presser foot and are best sewn with a Teflon coated presser foot.

The good news is that the feed dogs can work to your advantage. Anytime you need to ease one piece of fabric to another (i.e. sew a longer length of fabric to a shorter one as is often the case with shoulder seams, sleeve caps, or princess seams) you can place the larger length of fabric on the bottom and allow the feed dogs to ease it right into place for you. Just be sure to place pins at each end of the seam and a couple in the middle to keep the easing even.