Cutting Bias Strips (of Consistent Width)

bias finished top

For a long time I avoided using bias finish on my necklines and armholes even though  I preferred the look of bias to facings.  It wasn't only the sewing of the bias I found difficult, it was cutting the bias strips so that the width was consistent.  The methods I tried were (a) drawing chalk lines directly on the fabric, and (b) washing the fabric with starch to give it some stability.  Neither of these worked for me.

Drawing chalk lines on some fabrics is very hard; you sometimes can't see the line on patterned fabric (and the instructions you see in videos or tutorials always seem to show the person doing it on plain fabric), the chalk catches and pulls the fabric, the fabric moves as you draw on it... the list goes on.  I never got consistent width bias strips even on the more stable fabrics.  Trying chalk lines on viscose was a disaster and the width across the strip varied up to 1cm (.38-inch).  Washing the fabric in starch didn't work for me, and the spray on ironing starch was also next to useless.

The most frustrating thing of all was to spend a lot of time cutting bias strips to end up with strips that quite uneven, even when using stable fabric.  If I a slippery or unstable fabric such as drpaey viscose, it was impossible.

The way I now do it results in consistent width lengths of bias. It's easy to draw the bias lines and easy to cut.  It does involve some work, but anything worth doing is worth doing well, and anything worth doing well often takes time. That's my motto anyway.

Buying Bias Strips

While you can buy already made bias strips, it is just too expensive, at least here in Australia, and at least for me.  If you have a good income and have more money than time, you could choose to buy bias strips, but if you want the bias tape to be the same as the self fabric, you also have to do the work.  I have more time than money so I always make my own.

bias amount 1 metre

In Australia ready-cut bias is about $1 a metre, and there isn't a lot of choice in colour or quality.  Of course if you have enough fabric left over from your self fabric, you can make some bias strips from that, but sometimes you might not end up with enough fabric to do so.  On the flip side, sometimes you have quite a sizeable piece of fabric left over from a project that is not enough for a garment, but would be great to have as constrasting bias for a future project.

Note:  In most of my articles I use inches by default, and also add in the metric equivalent. As I don't know the price of bias and fabric in the USA and can only speak about what I know, so in this case it makes sense to give the examples in my life, and that means metres and $Australian.

To give an idea of the prices difference, here in Australia, between cutting your own bias and purchasing a packet from somewhere like Spotlight.

  • Birch bias, packet of 5 metres, is $5.00 at my local Spotlight Store.
  • I use voile which costs about $4.00 per metre from EM Greenfields in Sydney.   One metre of fabric will make at least 27 metres of bias that is 4cm wide.  This is based on fabric that is 110cm wide.  If the fabric is wider, I'll get more.  If I cut the bias thinner, I'll get more.  The cost of the bias strips made with the $4 a metre voile is therefore about .14 cents a metre.  (See the image; I did the maths in Illustrator while creating the graphic).
  • An added expense (not shown in the image) is the cost of the fabric you use to stablise the bias. In the case of the basic voile, I only use one layer of fabric.  With a slippery fabric that moves all over the place, I'll sandwhich that in between two layers of fabric.  I use very cheap fabric, leftover bits of fabric, old sheets etc, for this purpose. You can usually buy bits of fabric or old sheets at thrift stores very cheaply.
  • After accounting for the cost of the fabric used for stabilising, the cost per metre increases from .15 cents to .18 cents (one layer to stabilise) or .21 cents (two layers).   Still much cheaper than $1.00.

Constrasting & Self Bias Strips

cutting consistently even bias stripsI won't always be able to make matching bias because sometimes the self fabric does not have enough bias stretch, or sometimes there is not enough self fabric left over.  Therefore I I tend to make batches of bias that can be used as a constrasting design feature (see first image on the page with the black bias used with grey linen).  I will make a batch of bias strip from a 1-metre piece of fabric, and end up with about 27 metres of bias.  I generally try to have a stash of black, white, blue and another colored bias on hand; when the color runs out, I'll make another batch.  If I have 1 metre of good fabric that has good bias stretch leftover from a project, I will also make make up some bias from that to use as a contrast on something else.

Therefore I usually have a number a pieces of plain and patterned bias strips on hand for future projects.  If the self fabric does not have much bias stretch, I'll use of of these contrasting bias strips; if the self fabric has enough bias stretch and I have enough fabric, I'll make matching bias.

In this image the blue strips at the front are the bias; the polka dot fabric is the 'scrap' fabric I on which I use to draw the bias lines.  (Although this 'scrap' fabric was actually not cheap, it was leftover from something else and I had no other use for it.  It had sat in my scrap box for a couple of years).

Cutting Your Own Bias Tape

The method I use is to draw the lines for the bias on a disposable piece of fabric .  This piece of fabric needs to be the approximate size of the piece of fabric from which you want to create the bias strips.  It is really useful if this scrap fabric has some selvedge on it as this makes it easy to line up with the self fabricand will be exactly on the bias.  It also needs to be a stable fabric that you can draw on easily with a pen, pencil or texta.

Cutting Bias Tape: Image 01

Draw the lines on the piece of fabric at right angles to the selvedge. To achieve this:

  • Draw a square based on the selvedge, mine is about 3 inches.  (It you don't have a piece of fabric with the selvedge attached, just make sure you start off with a right angle, as shown by the yellow arrow).
  • Draw a diagonal line dissecting the square.
  • This is the base line that you will use as a guide for all the other lines.
  • I use a thin texta that does not bleed.  I always use a textra, not just for the purposes of illustration.

cutting bias tape 01

Cutting Bias Tape: Image 02

It so happens that the width of my patternmaking ruler is 4cm, and this makes it very easy for me to draw parallel lines to the original line. 

cutting bias tape 02

Cutting Bias Tape: Image 03

If you don't have a ruler the desired width of your bias tape, make sure you measure out at 3 places before drawing the lines.

cutting bias tape 03

Cutting Bias Tape: Image 04

Continue drawing the parallel lines until most of the fabric is covered.  (Your decision on how short the shortest pieces will be at the edges.  Remember you can sew bias strips together).

cutting bias tape 04

Cutting Bias Tape: Image 05

Put the self fabric underneath the cutting guide fabric, making sure the selvedges line up.  (For the purposes of this photo I left a bit of the self fabric peeking out).

cutting bias tape 05

Cutting Bias Tape: Image 06

Do not pin the fabrics together, just hold down and cut. Using a pattern weight is helpful. (Note that in this image the top fabric has moved a little; this was becaused I moved the whole ensenble in order to take this photo.)

cutting bias tape 06

Cutting Bias Tape: Image 07

If making bias from a large piece of fabric (e.g. 1 metre), it is essential you have enough space for the whole piece to lay flat all the time you are cutting it.  If you don't have enough desk space, you will need to do it on the floor.

cutting bias tape 07

Cutting Bias Tape: Image 08

When making bias from a large piece of fabric, draw the original square a number of times to ensure the bias line is correct.  Dissect the corners through two or three squares.

cutting bias tape 08

Cutting Bias Tape: Image 09

Using a pattern weight as you cut helps make sure the fabric layers don't move.

cutting bias tape 09

Cutting Bias Tape: Image 10

The resultant bias strips are a consistent width.

cutting bias tape 10

Cutting Bias Tape: Final Note

Important!:  If you are cutting bias from fabrics that are very drapey and/or slippery, putting an additional (throw away) layer of fabric underneath the self, i.e. sandwiching the self fabric between 2 layers, will ensure that the fabric doesn't move and you end up with perfect width bias.  This can be any cheap fabric as long as it has some stability.

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