In this month’s Love Sewing magazine (issue 24 on sale now), my Q&A is all about bias. “What is the bias?” “Why is it important?” “What is bias binding used for?” and “How to sew hems which cross the bias”. Here’s one of the questions in full:
What is the bias in fabric and why is it important?
OK, if you’re new to dressmaking you may have heard the terms “bias cut” and “cut on the bias” often used to describe dress or skirt styles. These styles usually cling, but then flare at the hem with a lovely drape and swing by using the natural stretch that occurs in all woven fabrics.
Picture © Julian Ward
Woven fabrics are all made from intersecting threads set at right angles to each other and these form the lengthwise direction of the fabric (straight grain or grainline) and the widthwise (crosswise or cross grain) direction. If you imagine a line at 45 degrees to these threads, this is what’s called the bias and it has a bit of natural stretch or bounce where the 2 sets of threads can move against each other.
The bias is important because of this stretch, not only for when a whole garment or garment piece is cut “on the bias” but also when a part of your garment, for example, a seam or hem, runs along the bias direction, as it will be prone to stretching out of shape and will need careful handling.
These areas of garments tend to run along the bias and are prone to stretching:
- Side seams on flared skirts
- Pocket openings
- Round and v necks
- Very rounded waist edges ie. waists on circle skirts
- Hems of flared garments.
What to do to avoid stretching:
- Staystitch the edge before working with it
- Use staytape along the edge
- Understitch the seams once they are sewn
- Gentle handling – don’t pull and stretch the edges when, for example, trying on a partly made garment
- Hang garments with hems that cross the bias overnight to allow them to “drop” ie. for that bit of the hem along the bias to stretch a bit with the weight of the garment, so that you can then trim and level off the hem before finishing it.
- Use a very narrow double turned hem by hand or machine or the method described below.
So there you have it; the bias in all its glory! Don’t be scared of working with the bias, all it needs is a bit of extra TLC and it will do you proud.