A practical guide to cutting on the bias
When Madeleine Vionnet first cut garments on the bias, nobody had ever before seen garments that draped with such elegant fluidity.
The sleek silhouette defined the evening wear of the 1930s, and was revived in John Gallianos’ slinky slip of the 1990s.
It’s a sort of sorcery, garments with minimal darts and panels that slip over the form of the body and mould to its shape. Beautiful cowls and drapes become possible.
With Bias cutting you can achieve really high end results, and make some garments you can be proud of.
What is the bias anyway?
Simply stated, the true bias grain of a woven textile is a 45 degree angle from the selvedge (straight grain), the key word here being woven.
Many fabrics used in fashion are not woven textiles, with a warp and a weft grain, and therefore don’t actually have a true bias, and are not suited for garments cut on the bias.
These fabrics are:
- Stretch fabrics are usually knitted
- Lace and mesh have a net construction.
- Felt is constructed by matting the fibres of wool
- Coated cloth is often stiffened to the point where the cloth no longer behaves like a woven.
Many fashion students and even professional dressmakers make the mistake of trying to cut an inappropriate piece of cloth on the bias, which is unnecessary and can be really wasteful.
It can also drape unevenly or bubble if there is more stretch in one direction of the cloth than the other, or if certain elements of a textile are more dense.
Not all fabrics necessary require being cut on the bias for a better drape, for example, cutting fine Chantilly at a 45 degree angle is not necessarily going to create more drape in the garment.
That is not to say that there is no reason ever to do it, you may want to experiment with the directions of a striped, printed or ribbed design, or accommodate a motif, but generally, a woven cloth is the way to go when cutting on the cross. When in doubt, drape the fabric in front of a mirror or on a mannequin and look at the way it falls when draped on the cross, you may find that that your cloth is actually better cut straight.
If you understand how cutting on bias creates the characteristic soft stretch and drape of a bias cut garment, it helps you decide which fabrics are suitable.
A close up view of a woven fabric reveals tiny squares created by the fibers of the weft and the warp, a fairly stable structure when hung along the straight grain. But turn that same cloth by 45% and you have tiny diamonds, and they can collapse, creating a cloth that stretches and clings.
The downsides to cutting on the bias:
- Cutting on the bias uses more fabric and creates more waste, the seams are more difficult to stitch, they have a tendency to wobble. But once you get the hang of it the results can be really beautiful.
- Bias cut garments do tend to be somewhat unforgiving and show every lump and bump as they sit more softly against the body, That’s one reason my bias cut garments are always lined, and why I often recommend a high quality foundation garment like spanx for bridal or occasion wear.
Tips and tricks
Make sure you follow these tips for the best bias cut garments:
- It really is necessary to cut at a precise 45 degree angle, otherwise you will get an uneven drape, roping and bubbling, those bias cut straps just wont fold smoothly and your seams wont lie flat. Trust me, guessing the 45 degree angle is almost impossible. Get your measuring tape out and make absolutely sure.
- You need to cut your cloth open, not on the fold, and preferably copy any pattern pieces that require a left and a right side so that you can lay the whole garment out on your fabric.
- That big piece of fabric is tricky to cut on a small table, but don’t let any of the cloth hang off the edges, it’s going to pull everything while you’re cutting, rather fold the excess cloth up carefully.
- Use a pattern that has been specifically designed to be cut on the bias. It will probably be a little bigger than a regular pattern to allow for the cling of the cut.
- Bias cut patterns may also include a larger seam allowance. A bigger seam allowance helps the way a bias cut seam lies, as well as giving you a little more to work with, when stitching or altering.
- When stitching on the bias, don’t get too hung up on matching your seams together exactly, yes, match your seams, but not if it makes the fabric pull to do so.
- I will often hang up bias cut pieces to “drop out” for a few days before I actually stitch them together, especially for silks and satin which tend to drop a lot. I also hang the garment for a few days to allow the hem to drop before cutting it straight and then stitching it. You will get a feel for it.
This is a process that really requires special attention detail, but if you can master it, you can truly create the most beautiful garments that will leave you standing out from the rest of the crowd