Bias Tape

Bias tape or bias binding is a narrow strip of fabric, cut on the bias (UK cross-grain). The strip's fibers, being at 45 degrees to the length of the strip, makes it stretchier as well as more fluid and more drapeable compared to a strip that is cut on grain. Many strips can be pieced together into a long "tape". The tape's width varies from about 1/2" to about 3" depending on applications. Bias tape is used in making piping, binding  seams, finishing raw edges, etc.

Commercially available bias tape is available as a simple bias tape, single-fold bias tape, and double-fold bias tape. Single-fold bias tape is bias tape that is folded in half lengtwise on its center line, wrong side together, and pressed. Double-fold bias tape is single-fold bias tape where each half is again folded in half lengthwise, wrong sides together, and pressed.

See also trim (sewing).

See also twill tape, sewing, tailoring , dressmaker, zippers , rhinestones , rivets , sequins , velcro, trimming

Cut at 45 Degrees for Stretch and Drape

Bias tape, also called bias binding, is a narrow strip of fabric cut on the bias, known in the United Kingdom as cross-grain. The strip's fibres, being at 45 degrees to the length of the strip, make it stretchier as well as more fluid and more drapeable compared to a strip that is cut on grain. That angle is the whole definition. A strip cut along the grain follows the straight threads of the fabric and resists curving, while a bias strip can bend, stretch slightly and settle around a curve without puckering. This is why bias tape is chosen for edges that are not straight: necklines, armholes, curved hems and rounded corners all need a binding that can follow their shape, and a straight-grain strip would wrinkle or pull at exactly those points. The bias cut trades a little stability for that flexibility, so the tape must be handled without stretching it out of shape as it is sewn.

Width and length are adaptable to the job. The tape's width varies from about half an inch to about three inches depending on applications, with narrow tape used for fine edges and piping and wider tape used where a broader binding or facing is wanted. Many strips can be pieced together into a long tape, because a single width of fabric yields only limited bias length; joining strips end to end, with the joins spread around the work, produces the continuous length needed to bind a whole garment edge. Commercially available bias tape is sold ready-made for convenience, in colours and fabrics chosen to match or contrast with the garment. Making tape at home from the garment fabric itself gives an exact match, while bought tape saves the cutting and joining work and gives a consistent, pressed fold that is ready to stitch.

Single-Fold, Double-Fold and Uses in Sewing

Bias tape is available in distinct folded forms, and the names describe exactly how the strip has been prepared. Commercially available bias tape is available as simple bias tape, single-fold bias tape and double-fold bias tape. Single-fold bias tape is bias tape that is folded in half lengthwise on its centre line, wrong side together, and pressed, so it presents one folded edge and two raw edges that are enclosed as it is applied. Double-fold bias tape is single-fold bias tape where each half is again folded in half lengthwise, wrong sides together, and pressed, tucking the raw edges inside so the tape can wrap an edge cleanly with no raw fabric showing. Choosing between them depends on the finish required: single-fold suits facings and edges that will be enclosed, while double-fold suits visible binding where both sides of the edge will be seen.

The uses follow directly from the construction. Bias tape is used in making piping, binding seams, finishing raw edges and other sewing tasks where a neat, flexible edge is needed. For piping, the tape wraps a cord and is stitched into a seam so a raised, defined line appears along the edge. For binding, the tape encloses a raw edge completely, protecting it from fraying and giving it a clean outline that can match or contrast with the main fabric. For finishing, it replaces a turned hem on a curve where a straight hem would not lie flat. Bias tape belongs with related sewing trims and notions such as twill tape, which is cut on grain for strength rather than stretch, and with the wider family of trimmings used by dressmakers and tailors. Understanding the 45-degree cut explains all of these uses at once: whenever an edge curves, stretches or needs a smooth wrap, a bias strip will lie flatter and move more naturally than any straight-cut alternative.