What is Bias cut ?
Bias cut basically means cutting the fabric on a 45 degree angle to the straight grain so that the fabric will drape itself contouring to the shape of the body. To put it simply fabric is cut at a diagonal angle. It is figure flattering , that is what the fuss is all about. Madamme Vionnet made this cut fashionable with glamorous bias cut evening gowns and the fashionistas just lapped it up. The fluidity and drapabilty of garments made when cut in this manner makes this the most desirable way to cut when making couture clothes.
What are the advantages of a garment made with fabric cut on the bias
- Great drape
- An attractive fluidity and movement
- More stretch
- No fraying of fabric edges
- Gives a slim silhouette
Checkout the way the bias cut gown by Alexander McQueen worn by Pippa Middleton for the royal wedding drapes so well and accentuates her curves so nicely
There is a reason why the bias cut gives the attractive looks that it does – When fabric is cut on the bias grain the air space in between the warp and weft threads of the fabric disappear and the fabric becomes supple and soft. Have you noticed that a fabric which is cut on the bias does not fray. Just checkout the pieces I have cut out for the tie pattern & sewing tutorial here. The big top piece is cut on the bias and the fabric edges are intact; no fraying at all. The other piece in the back is cut on the straight grain and it is unraveling like a mad dog.
How to cut fabric on the bias grain
The True bias grain forms a 45° angle to the selvage. To find the true bias, fold the lengthwise grain of the fabric (selvage) at a right angle so that the lengthwise grain lies parallel to the crosswise grain.The true bias is usually used in making bias binding tape, facing etc Other diagonal folds or cuts at any other angle may also be called bias, but they give less stretch than does a true bias.A true bias is used when making garments with the most drape
If done well bias cut can give you a garment which is extremely flattering and will make you look leaner . There are some guidelines you should follow when you cut on the bias grain. Also some rules to adhere to when sewing the fabric which is cut on the bias. Nothing is too much for a well fitting garment.
1 You need more fabric when placing and cutting the fabric on the bias grain. So plan ahead and calculate the yardage accordingly . Checkout the post on fabric yardage on more details. I always add 1 meter extra for a knee length dress.
2 Choose a simple pattern – Sewing the seams of the bias cut fabric is a pain because of its stretchiness . The ripples in the fabric especially if it is super soft like satin can make you palpitate; so keeping the seams to the minimum is what I do. Donot unnecessarily add or choose a pattern with extra design details like yokes or darts. Checkout this cowl top pattern which is cut on the bias. This simple tunic top also works well when cut on the bias.
3 Handle the fabric with care after it has been cut on the bias. Ensure that you are not stretching the fabric even more . A little bit of strechiness is good but you donot want it to sag out of shape so Handle with care.
4 Seams which are cut on the bias may need to be stabilized with a stay tape. You can use a fusible stay tape or the selvedge of the fabric itself as stay tape
5. Choose fabric with care – Not all fabric drapes well when cut on the bias grain. For a fabric to drape well on the bias the weave, weight, and softness should be in harmony. For example organdy fabric which is stiff would not look as well as silk when cut on the bias grain. An open weave is also preferred for a bias cut. Very heavy fabric also maynot hang well when cut on the bias so donot choose heavy fabric as well . Silk, wool crepe, silk crepe work very well when cut on the bias grain;Wool challis, soft cotton, linen are also good . Polyesters and rayons may look the perfect fabric for bias cut but sadly they are not. Generally fabric which is woven with natural fibers work well when cut on the bias grain.
When I am at the fabric store I always test out the fabric I am intending to buy for the bias cut by folding it diagonally and trying the stretch.
Also the first time you cut and sew a bias cut fabric decide on a simple fabric which is easy to handle like linen . Donot choose that slippery satin which will give you real pain especially when it comes to sewing the seams and finishing the hem and necklines. Also avoid stripes which may have to be matched especially if there is a center seam
6. Bias cut garments needs more ease – When deciding to sew a dress on the bias, alter the pattern so that it has a bit more ease than the pattern for a dress with a straight grain cut. Especially if you are are on the curvy side. Something like 6 inch ease in place of a 2-3 inch ease you usually give.
7 Bias cut needs more seam allowance – give a minimum of 1 inch seam allowance to all seams . You will notice that when you wear the garment the seam allowance will narrow out because of the stretching
8. It is better to cut the pattern in a single layer rather than folded . There is a chance of the fabric slipping and distorting when cut. Make a paper pattern and lay it stretched open on the fabric on the true bias grain. Mark around the pattern. Cut away the traced lines.
9. Hang the bias cut garment for 24 hours after you have finished sewing everything but the hem . Any unwanted stretch will be evened out by this hanging. Cut any hanging fabric and proceed to hem.
11. A tight zig zag stitch is the best stitch for sewing the bias cut seams as it will give some stretch to the seams. You may need to stretch the seams a little bit as you sew.
12 Press as you sew – this adage is true for bias cut fabric seams as well. And ensure that you are in no way ironing. Ironing involves stretching and that is a strict no no for bias seams. Checkout this post on pressing cloth for sewing
13 To finish the necklines and armholes you can use a bias facing.
Checkout this post on cutting fabric on the bias for bias binding
14. A center seam maybe a necessity when cutting certain fabric on the bias. When you stretch the fabric you may find that it stretches differently on the lengthwise grain and cross wise grain. If this is the case after you have cut and sewn the fabric it will hang uneven. Because a bias cut will get half half from the lengthwise and crosswise fabric grain. In this case you should cut the pattern with a center seam so that you can cut the pieces from the same grain . A beautiful chevron effect can be made by cutting striped fabric on the bias and joining with a center seam
Fabrics most suitable for Bias cut garments
Rayon, Silk, Rayon Challis, Wool Crepe, silk crepe, Silk Charmeuese; Most natural woven fabrics with open weave drape well
Fabrics not suitable for bias cut
Microfiber, muslins, unwashed Quilting cottons, Irish linen & Organdy; Fabrics with a tight weave.