Continuous Bias Tape Tutorial

My students in the Intro Sewing class all make continuous bias tape. I make it right along with them each month, and give them a copy of printed instructions courtesy of the Dread Pirate Rogers, but have always wanted to have better photos to offer. While I was busy making the changing pad cover for New Baby, I went ahead and shot some photos of the CBT process with the gingham I used to wrap the piping.

Bias tape, very simply, is just a strip of fabric cut on the bias--the 45 degree angle across the grainline of the fabric. It has the most give you can get out of a particular cut of fabric, and allows you to bind curves and seams, wrap piping, or edge finish a project. It's great stuff, I use it all the time, and knowing how to make and apply it will revolutionize your sewing--honest.

You can easily make bias stips just by slicing across that bias line. This is the technique I use when binding armholes or necklines, something relatively short. When I need longer pieces, though, I'd be forced to stitch each of those strips together into one longer strip, and that's a huge pain in the behind, as far as I'm concerned. It's much easier to make CBT--Continuous Bias Tape--by stitching a larger piece of fabric together on the bias and then cutting THAT into strips. You get piles and piles of bias tape this way, and you get the freedom to choose any fabric you want rather than being limited to the solid, poly-cotton blend available at the fabric stores. You can also manipulate the width of the bias tape better--I'll elaborate on that at the end of the post.

So, how do we make CBT? Golly, I'm glad you asked.
Here we go:

Start with your fabric.  The reason I prefer the Dread Pirate Rogers' instructions is that, as opposed to lots of other methods (Martha's included!), she starts with a rectangle of fabric rather than a square.  Since a cut of fabric IS a rectangle, this makes more sense to me, and is more economical.  Here I've rolled out some apple green gingham:

Cut off a length of your fabric.  How much depends on how long you want your finished bias tape to be, but if you've never done this before, I'd start with about half a yard--that measurement seems to make a piece that's easy to manipulate without being overwhelming:
Trim off the selvedges of your fabric.  (Selvedge edges shrink at a different rate than the remainder of your fabric, and should always be removed--even if it feels like a huge waste of a straight edge!).
Fold one selvedge over to meet the top edge of your fabric, forming a 45 degree angle on one end, and a triangle on top of the main portion of your fabric:
Trim this triangle away by placing your blade along the folded edge and cutting:
You should end up with two pieces of fabric, like this:
Move the triangle to the OTHER end of the original piece of fabric, placing selvedge edge to selvedge edge.  You'll know you got it right if your shape is now a parallelogram rather than a rectangle:
Place the triangle and the original fabric right sides together, selvedges touching:
Stitch a seam along the selvedge edge.  I use the edge of my presser foot as a seam allowance guide (most presser feet are approximately 1/4" away from the needle, giving you a 1/4" seam allowance), but you can use whatever seam allowance you choose--just remember what it was so you can give the next seam the same allowance:
Press your seams allowances open (and consider if it's time for a new ironing board cover--oh my!):
You should now have a piece of fabric that looks more or less like this:
Starting at one angled edge on the WRONG SIDE of the fabric, begin drawing lines parallel to the bias angle and marching across the fabric.  I use a quilting chalk for this, but whatever marking tool you prefer is fine.  I space my lines with a quilting ruler, too, since it's clear and acrylic and sticky on the bottom, making my marks more consistent--and consistency is the KEY with this step.  It doesn't have to be perfect, but the closer it is the easier the next steps will be:
How far apart you space the lines is dependent on how fat you want your bias strips to be.  If you've not done this before, may I suggest that FATTER IS BETTER to begin with--you can always scale it down when you feel more confident with the technique.  For this example (and to wrap the huge, fat piping in my project) I used the width of my ruler as a guide:
At the other end of your fabric, you may not have a full width left, like I had in this example.  Cut that paltry little vestige off to make sure each of your strips is of equal size:
OK, here comes the confusing part, at least for most people.  Our goal is to create a TUBE of fabric, then cut that tube apart to make a long strip.  We DO NOT want to stitch a tube, then cut it apart into a series of donuts, so the edge that we stitch needs to be slightly offset.  In order to achieve this, we're going to number the lines we just drew, starting at the edge with number ZERO, and moving across each line sequentially (the first chalk line is ONE, the second is TWO, etc):
On the BOTTOM of the fabric, we number again, but this time, we start with number ONE at the edge, and the first chalk line is TWO and the second is THREE...  The point here is that the TOP of one chalk line never has the same number as the BOTTOM of the same chalk line (the printed instructions have a good illustration of this):
Once all the lines have been numbered, bring the two straight edges (i.e. the top and bottom of your piece of fabric, NOT the bias edges) together, right sides together.  We're going to match the numbered lines to one another--line #1 meets line #1, line #2 meets line #2, etc.  Pin these in place.  This step feels AWKWARD, as it makes a twisted tube of fabric--that's OK, since we WANT it to be offset:
Bear in mind that as you match these lines up, they're at an angle, so they won't match one another on either side of the fabric--they'll actually cross one another.  You're going to put in a seam that will run through the point at which they cross.  Just keep pinning and matching the best you can--it's much more important that your seam lies flat than that your numbers and lines match flawlessly.  You should end up with something hopeless that looks like this, and will almost certainly be thinking, "This lady is nuts, and this is never gonna work."  Hang in there!
Take your twisted tube to the machine, and stitch a seam with the SAME ALLOWANCE as the last seam you stitched, whatever that was.  Remember to keep reaching beneath your work and making sure that there are no catches or random bits of fabric getting caught under the needle--you really don't want to have to do this step over:
Press that awkward seam open.  A sleeve board is great for this, but an ugly, stained ironing board will work, too (note to self: make new ironing board cover):
OK, this is where the magic happens.  At each end of your tube, you have a little tail of fabric hanging off.  You also now have a SINGLE line of chalk going around and around the fabric.  Choose one end of the tube--doesn't matter which one--and begin cutting the line next to that little tail:
KEEP CUTTING all the way around, through a single layer of fabric, and watch as the tape begins to take form:
When you come to one of your seams that you've pressed open, cut right across it and keep going:
Ta da! The finished product: yards and yards of bias tape from your favorite fabric. I make lots of this at one time when I have the time, then store the rest for the NEXT project. That way, I get the enjoyment of it and I use my time economically:
Hope the images helped, and that the length of the instructions doesn't intimidate--the first time can be a rough road, especially if you're teaching yourself, but after that it's SUCH a quick, simple process that I know you'll make it a regular part of your sewing skill set.

Happy sewing, everyone!