Updated: Aug 27, 2022
'Bias' is a dirty word in quilting. I'm always amazed at the lengths quilters go to avoid working with a bias edge. This usually means a lot of extra steps and a LOT of extra work that is at distinct odds with my lazy quilting mentality. It's MUCH easier to just learn to manage the bias stretch. With some easy habits and some practice, you too can master those tricky bias edges. Here are 12 tips to manage the stretch.
What is a bias edge?
First thing's first, if you're not familiar with the term, a bias edge is one where the threads that make up a woven cloth, such as that routinely used for quilting, are neither parallel nor perpendicular to the cut edge. If the threads were perpendicular or parallel, this would be known as a straight of grain cut and when the cloth is tugged on, you would be tugging directly on the length of those fibers, just like tugging on the string. Since the fibers are cotton and not very stretchy by themselves, this means that the cloth itself is also not very stretchy in that direction. However, if you were to cut the cloth at an angle to those perpendicular threads and tug in that direction, you'd be essentially pulling the fibers apart rather than along their length. This allows them to shift and slide a bit in their woven configuration leading to quite a bit of stretch.
Zhang, 2014. DOI: 10.1364/AO.54.000966
The bottom line is that bias edges are pretty stretchy and easy to distort whereas straight of grain edges are not. This can make it more difficult to maintain accuracy and match points when there is a lot of bias in the mix.
Bias edges form any time you make a cut that is not a 90 degree angle such as when cutting triangles, diamonds, kites, or basically any shape that is not square. That's a lot of shapes! So if you're going to avoid bias edges, you're limiting yourself to some pretty boring designs (in my obviously humble and non-biased opinion).
Tips and Tricks
So how do you work with these bias edges without a bunch of extra work and frustration?
1. Lower your stitch length - cotton thread (which you should always be using for piecing) isn't stretchy so the more of it and the more stitches you have holding things together, the less the cloth can stretch. I do this whenever I piece (because I'm lazy and don't want to have to change it regardless of if I'm sewing a bias edge or not). My piecing stitch length is always set to 1.8 mm whereas a standard stitch length on most sewing machines is around 2.5 mm.
2. Lower your presser foot pressure - if you have this option, take advantage of it. If your presser foot is pressing down too much as you take stitches, it can distort the bias edge. Your presser foot pressure is too much if you notice your seam becoming a little bit rippled.
3. Press, don't iron - If you want all the details about the difference, check out this blog post. Suffice it to say: pressing is up and down, ironing is back and forth. If you iron, you can easily push those stretchy edges out of alignment. Pressing just sets seam allowance without pushing too much laterally, therefore, minimizing distortion.
4. Use a non-flanged 1/4" foot - the flange can run into dog ears and seams pushing them out of the way which distorts the fabric.
5. Allow the feed-dogs to move the fabric - you're hands and/or stiletto are there as a guide only and shouldn't be tugging or pulling on the fabric at all as it goes under your needle. Let the machine do all the moving.
6. Use a clapper - a tailor's clapper is simply a block of wood that you sent on top of your seam after ironing it. Besides making things super flat, it sucks the heat and/or steam out of the fabric much quicker than letting it air cool. Since hot fabric = stretchy fabric, rapid cooling will help minimize distortion.
7. Use leaders and enders - You can read more about this here, but essentially leaders and enders secure your thread tails and minimize the opportunity for your fabric to get chewed up by your feed dogs which means less opportunity for distortion.
8. Slow down a bit - this will give your feed dogs a better chance of evenly feeding the fabric under the needle. While most modern sewing machines can sew super fast, they're still not nearly as effective at those speeds. You're more likely to have skipped stitches and shredded thread at high speeds - and your feed dogs aren't nearly as precise. Slow down slightly, you'll get better results.
9. Use a straight stitch needle plate - A straight stitch needle plate is the one with just a hole in it for the needle rather than a slit. When the needle goes to punch through the fabric, the smaller opening supports the fabric better, you guessed it, minimizing distortion. Your machine may or may not have come with one of these. I wouldn't necessarily go out and buy one, but if you have it, might as well use it.
10. Make sure your needle and pins are sharp - dull pins and needles require more force to puncture the fabric and can easily distort the fibers. Sharp, fine pins during pinning and a sharp sewing machine needle appropriate for the size of thread you are using will make sure distortion isn't coming from those sources.
11. Starch your fabrics - as much as I hate it, starching is a great way to help minimize bias stretch. I use this as a last resort, but if you've exhausted other options, starch will make a big difference. Think of this like training wheels; use it if you're still learning how to deal with bias edges and then wean yourself off it as you get more comfortable. If I'm using it, I like best press (not an affiliate link), but use whichever brand you like best.
12. Minimize your seam ripping - I know, I know, no one ever intends to make mistakes. But if ever there was an argument for "just leaving it even though it's not perfect," bias edges are it. At absolute best, you might get 2 rips out of one pair of pieces. If it's not acceptable but then, just leave it, or if absolutely necessary, start over with new fabric. By the second rip, the pieces will be seriously showing distortion no matter how gentil you try to be and if, god forbid, you have to go in for a third rip, getting them back together with any sense of alignment will be next to impossible. It actually gets harder to achieve good alignment with every ripping session so if it's even in the ball part the first time, just Elsa that s*** and "Let it go!" Trust me, it's really the best option all around.
Hopefully, something in there will help you troubleshoot if you struggle with sewing bias edges. But, just remember, practice makes progress and, while it might feel awkward or impossible at first, you WILL get better with time until bias edges are a non-issue. You got this!