In couture sewing, elegant garments are bias cut. It’s used on gowns, lingerie and even
things like neckties. This tutorial will break it down on what this means and offer some
tips if you want to try it yourself.
What does working on the bias mean?
On fabric, you have straight grain and cross grain to describe fiber direction on woven
fabric. Many times, you’re putting your pieces on the straight grain so the grainline
arrow on your pattern is going parallel with the selvage.
Putting your pieces on the fabric diagonally is putting it on a bias. If the grainline
arrow is at a forty five degree angle between the straight and cross grain, this is considered
true bias. But why would you want to cut out your pieces
this way?
The benefits to cutting your pieces on the bias are:
Garments are more figure flattering and slimming It drapes better and has a softer, more delicate
look
It has stretch
It doesn’t fray and you don’t need to finish seams.
It doesn’t wrinkle as much
But there are things that make it tricky to work with too:
It stretches, which means pieces can distort and make it difficult to work with.
More fabric is needed to cut it on the bias.
You may want to alter patterns to increase ease and seam allowance.
When choosing a pattern, especially if you’re a bias beginner, choose a simple pattern with
minimum seams, darts and details, like a camisole.
You also need to be particular with fabric when first learning:
Don’t start off with silky, slinky, satin-y type of fabrics.
Don’t choose prints or stripes that need to be matched.
Don’t choose stiff, heavy fabrics that have little drape to them.
Choose a fabric that has natural fibers and is lightweight but still has some stability,
such as cotton, linen, or silk broadcloth.
Fabric on the bias has a tendency to lengthen after cutting. You may want to alter your
patterns to increase your seam allowance to 1”. You may also want to increase pattern
ease. If you increase the pattern by even a ½” and there’s four pieces making up
the bodice, that’s an increase of 2” overall ease added. This is a good place to start.
But make a muslin to test the fit and practice.
You can easily convert regular patterns for bias cutting by redrawing the grainlines.
First, draw a perpendicular line in the center of the current grainline arrow.
Fold the pattern so the line you drew is on top of the original grainline. Fold to make
a crisp crease.
Now repeat, folding in the other direction to create another crease.
Where these creases are, is the line you’ll consult to get true bias when doing your layout.
When cutting out your pieces, lay your fabric flat on a large table so nothing is hanging
off the edge of the table and it’s a single layer of fabric.
Use one of your True Bias lines on the pattern and make it parallel with the selvage. Measure
the distance between the true bias line and the selvage to ensure the line is perfectly
straight and parallel.
It’s not enough to simply lay all your pieces on the true bias but you need to put thought
into it. If you lay all your pieces the same way, Your garment may be unbalanced which
will cause seams to twist around the body.
Before I get into why this is the incorrect pattern layout
let me just talk about my pattern pieces, these are just smaller versions, just for this demonstration.
Just because I want to fit everything on screen at the same time and make it easier for me to point it out.
Now you will notice I have four bodice patterns.
Because normally you have the front, the back
You place maybe the front on the fold
and then you end up with a full piece.
But when you are doing this sort of sewing.
It's a good idea to actually break it up even if your pattern is not already like this.
So I took my front bodice, I made the opposite. So I have a right, I have a left and did the same thing with the back.
This just makes it a little bit easier to visualize you layout and also to make sure that you are doing your balancing correctly
Instead of trying to remember how you laid out a previous pattern, and then you have to unpin it and do the left side.
Now if you do do it this way.
Don't forget because you are going to be sewing the right front to the left front now.
You are going to have a seam here. And if your pattern says place on fold, you are going to have to add seam allowance to that.
So if you do do it my way don't forget to add seam allowance wherever you are going to be adding a seam.
So this is the incorrect layout.
And the reason why it is incorrect
is because, even though when you are doing your layout, you are not paying attention to the true bias line.
And making sure it is parallel with your selvage
Your grain line, the original grain line from our pattern
You will notice, they are all going in the same direction, so they are all parallel with each other.
You want to actually
want to change it from pattern to pattern.
This is why it is a good idea to have two true bias lines because you can flip it and you can have
either this true bias going parallel, or I can completely switch the pattern and this true bias is going parallel with the selvage.
For the correct version
maybe I will lay out this pattern and my grain line is going in this direction diagonally but I will take this pattern
I'll flip it.
So this grain line is going in this direction, but you are still using one of the true bias lines
in order to make it parallel with the selvage, so now I will show you the correct version, so it will make a bit more sense.
Here is with a correct layout, so you see grain line going this way
grain line going this way and they are perpendicular to each other.
Same thing over here, ones going this way and one is going this way.
Now, I can't just randomly pick which one goes in which direction. You have to really think about how it is being sewn together as a garment.
So if you think of the garment on your body, its basically a circle, it is going around your body, so you take one point
to start with. So I am going to start with my right front bodice.
What is going to be sewn next to this? It is going to be my left front bodice.
So this is going to be sewn on this line
so since these are going to be sewn together, I am going to make them opposite in order to make it balanced.
So I look at this grain line
this grain line and they are going
perpendicular to each other, so that is correct.
And you will notice my true bias lines
I just pick one, they are going parallel to the selvage
so now I am thinking OK.
Now that these two are sewn together, what is going to be sewn next to my left front bodice, so it is going to be this seam right here.
That's going to be the left back bodice. no now I make sure
this grain line is going in this direction, this one needs to go perpendicular, so you can see it is going perpendicular, so this one is correct.
What is going to be sewn to this piece? On this line right here is going to be the right.
So this needs to go perpendicular to this grain line here
and it is, so this is correct
and we have come back full circle.
This side is going to be sewn to this and they are already correct.
Normally, with any sewing you are going to do on a garment
it is going to be an even number of pieces. It is very odd that it would have five pieces.
So it should always work out if you are doing it correctly.
This is why you have to think when you are laying your pieces out and not just place them any way.
And if you are thinking why do I even have to separate
my bodice pieces and I can't just place this on a fold, or
place this and flip it and do it on the fold and just have two pieces and keep it simple, you can do it that way.
As long as you are still following this sort of balanced layout where
I have the front going in one direction for the grain line and the back going in a different direction.
This just separating it and having four pieces instead of two just makes it more balanced.
So that is the only reason I am doing it this way.
But you can definitely do it the other way as well.
If you do have a piece, you wish to place on a fold, don’t put on a fold.
Instead, cut out one side and then flip on the fold line and cut the other side.
If I only have two pieces, front and back, I’ll still have the pattern pieces going perpendicular to each other for balance.
You can use pattern weights and/or straight pins to hold the patterns, but I recommend using a rotary cutter to cut the fabric.
You really want to handle the fabric as little as possible.
Before you remove your pattern pieces, mark the stitch line on your fabric with fabric chalk, marker, tracing paper or a hand basting stitch.
This is important because you won’t be able to depend on the cut edge for an accurate seam allowance.
Because of the stretch-ability of bias cut, your pieces can stretch and distort during garment construction.
It’s a good idea, before starting, to stay stitch all raw edges.
You can use a regular length stay stitch and stitch inside the seam allowance about one eighth of an inch away from the marked stitch line.
When attaching two pieces together, you should use a lot of straight pins and avoid stretching your fabric pieces.
On your sewing machine use a brand new microtex or sharp needle.
When sewing a seam start one eighth of an inch away from the edge and use a stretch stitch or a narrow zig zag stitch with a stitch width of two and a length of five.
Let the machine feed the fabric through, don’t stretch it, so you won’t get rippled seams.
You can also try a walking foot to help. Also, use your stitch line as a guide.
The cut edge of the fabric will not be dependable so don’t use it as a guide.
Sew your garment seams in the same direction.
For example, start from the bottom of garment to top of garment. This consistency will help prevent ripples in the garment.
After you sew your seam, you can trim your seam allowance.
Bias cut fabric is really good about not fraying so you don’t have to finish the raw edges if you don’t want to.
Press instead of ironing. This means, you put the iron down for a few moments and then
lift up the iron to put it in a new spot. Don’t put the iron down and push it across
the fabric. You might cause unnecessary stretching.
If you have curved areas to press, utilize a tailor’s ham or roll to help.
If you need to use interfacing, consider using a knit interfacing since it’s also stretchy.
But it’s a good idea to eliminate facings and instead finish necklines with bias tape
binding or a narrow hem. If you need to stabilize a seam, use stay tape.
When not working on your garment, store it flat. Do not hang it on a hanger or dress
form to prevent stretching.
When it is time to hem your garment, let it hang on a hanger or dressform for about twenty
four hours to let it settle naturally.
For hemming, I recommend a rolled or narrow hem. See our videos to learn how to do this.
After you finish your garment, use steam to press it.
Most importantly, know that working on the bias takes time and consideration. Don’t
rush the process and allow yourself to practice on something simple. If you have any tips
on bias sewing, leave a comment below.
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