What is a walking foot and do I need one?

A walking foot has its own feed mechanism that moves the top layer at the same rate the feed dogs move the bottom layer.

On an ordinary foot, only the bottom layer is driven. The top layer is pushed forward slightly by the foot itself, so on anything thick, slippery or layered the two finish at different lengths. That is why a quilt sandwich comes out with the backing rippled, and why a plaid that matched at the pins does not match at the end of the seam.

Where it earns its price:

• Quilting — the reason most people buy one.
• Vinyl, oilcloth and leather, which stick to a standard foot rather than sliding under it.
• Velvet and pile fabrics, where the nap makes the layers creep.
• Matching stripes and plaids across a seam.
• Knits, where it reduces the stretching that produces wavy seams.

Where it does not. Ordinary single-layer or two-layer woven sewing. It is slower, noisier and bulkier than a standard foot, and it adds nothing.

Buying note. Walking feet are more machine-specific than most feet, because the mechanism has to sit correctly relative to the needle bar. Buy the one made for your machine rather than a generic — this is the foot where the generic version most often disappoints.