Bias: Definitive Essential Foolproof Guide! Sew Basic Series

Fact: sewing beginners often don’t know what “bias” exactly stands for…

I’ve decided to write about it after receiving some question like:

– What does “cut on bias” mean? –

– How can I cut on bias a rectangular shape, having its measures? –

– How can I lay a pattern piece on bias? –

A frequent beginner sewist’s mistake is simply to ignore how fabric is made and how its properties changes, depending on your pattern’s direction line-up.

If you’re completely unfamiliar with fabric, I’d suggest you to read my Fabric 101 post, where I’m explaining what are straightgrain, crossgrain and bias.

Today’s main dish is:

everything bias

Serger Pepper - Bias - Definitive Essential Foolproof Guide - Sew Basic Series

First of all, according to with wikipedia, let’s see what does bias (on textiles, at least…) mean:

The bias direction of a piece of woven fabric, usually referred to simply as “the bias”, is at 45 degrees to its warp and weft threads. Every piece of woven fabric has two biases, perpendicular to each other. Non-woven fabrics such as felt or (non-woven) interfacing do not have a bias.

Wha-wha-what’s? Ok, better put in an explaining pic:

Serger Pepper - Bias - Definitive Essential Foolproof Guide - Sew Basic Series

 warp (=straightgrain)  –  weft (=crossgrain)

Now, maybe you’re thinking:

“I have so many things to look at and learn, as a beginner! Couldn’t I skip this bias thing and cut randomly? Isn’t it the same?”

Short answer is: “No, you shouldn’t!”

Long answer is: “Absolutely no! Go on reading and you’ll know why!”

Remember that the same fabric, cut on grain or on bias, has completely different properties!

If you cut it on bias, your fabric will be:

  • slightly elastic
  • smoothly draping
  • more supple
  • not fraying
  • thinner (or at least it seems to be!)

Bias ramblings

  • Consider carefully all bias properties listed above while deciding if cut a pattern piece in bias or in grain, because sometimes you’ll need to stabilize a bias-cut fabric to avoid annoying wrinkles and bumps (as if buttons/buttonholes and/or zippers, or pockets are involved);
  • When a pattern(maker) asks you to cut a piece on bias, often it’s because this particular piece has to drape softly or stretch just a little. If you ignore this, you could end with a completely different result from what’s shown on your pattern’s cover!
  • A pattern cut on bias is often designed without darts, because it takes advantage of your bias-cut fabric’s natural stretch to add ease and fit well: cutting on grain will likely leave you with a garment you can’t wear at all!
  • A negative side-effect of bias-cut is that it literally eats more fabric: yardage are usually way bigger than traditional grain-cut patterns and leaves you with much more scraps (that, if you are like me, you’ll end piling here and there, just in case – never throw out anything!!!)

Ok, let’s go practical! Here are my

best tips for sewing with bias-cut fabric:

  1. Never. Pull. Fabric. I mean Never!!!

…or it will lose its shape: allow the pattern piece to keep its natural shape!

Remember that a fabric cut on bias is more elastic than the same fabric cut on grain, so, when you pull it, it extends:

Serger Pepper - Bias - Definitive Essential Foolproof Guide - Sew Basic Series

Serger Pepper - Bias - Definitive Essential Foolproof Guide - Sew Basic Series

Can you see how much it stretches, along the bias?

  1. Password: staystitching 

To stay on the safe side, simply add staystitching along the edges (remember: sew inside your seam allowances!), just after cutting your pattern pieces, and carefully sew without stretching!

Let’s take a look to the same bias-cut scrap of fabric, after staystitching it:

Serger Pepper - Bias - Definitive Essential Foolproof Guide - Sew Basic Series

Serger Pepper - Bias - Definitive Essential Foolproof Guide - Sew Basic Series

Look how much less flexible is now!

  1. Go slowly!

When sewing bias-cut fabrics, better sew little portions of your seams, stop and repeat: this will help you avoid pulling therefore distorting your pattern piece.

  1. Press seams without sliding your iron on your bias-cut garment surface.

You’re right, this is a rule of thumb for any press-while-you-sew advice, but on bias is mandatory, or you’ll certainly end with a distorted pattern piece, no more matching with the other pieces of your pattern (it could be longer, shorter or simply morphed in shape).

  1. How do I hem a bias-cut garment?

Let it on a hanger (or better on a dress form, if you’re so lucky to have one!) a day or two before hemming it.

This is the only way: leave it alone, it will “sit” and relax (Cup of tea?) and finally have a nice straight hem on your bias-cut garment. If you skip this step, your hem will be uneven, with a potentially unwanted (and completely random) hi-low effect!

  1. Stabilize seam allowances, when needed

Use  a lightweight woven fusible interfacing (cut on grain!) if you have to add a zipper on edges of a bias-cut garment (often a skirt or a dress, but could be a blouse too!); some handbasting can also help you avoiding ripple marks – do not skip it here! 

  1. Stabilize when adding buttons

If you’re going to add buttons and buttonholes on a bias-cut garment, stabilize it adding interfacing scraps behind them.

If you have a woven interfacing (my favorite, I don’t like non-woven kind!), cut it in grain and not in bias, or your pattern piece will stretch also if interfaced!

  1. Save time on finishing seam allowances, since bias doesn’t fray!

Eventually you can reduce them with pinking shears.

I have to confess, I always skip this step because:

a) I don’t own pinking shears;

b) I’m lazy!

  1. What if I have to sew together a bias-cut piece to a grain-cut piece?

Always put the bias one right above the feed dog and the other on top: the bottom layer will be eased in while the top (on grain) layer will help stabilize the seam!

  1. Look at your fabric closely before cutting!

Consider adding a central seam on a bias-cut garment’s front and back pieces: if your fabric’s crosswise and lengthwise threads looks quite unequally distributed, add it!

The two bias directions often don’t drape similarly (depending if it’s crosswise or lengthwise threads on up-down direction) and you could end with a crooked garment! Better add a central seam (and if you’re using a striped fabric you’ll have a free chevron shape!!)

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That’s all for today: next week I’ll show you how to quickly and easily cut rectangular shapes on bias if you only have required measurements (and no pattern pieces).

 

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About the Author:

Hi there! I love sewing, creating my own patterns and refashioning pre-loved clothes... If you love the same things, why not be friends? See you on Pinterest http://Pinterest.com/MammaNene

19 Comments

  1. Federica January 13, 2014 at 10:17 - Reply

    ops averlo letto prima, ho appena tagliato il collo del test per dritto….

    • Mamma Nene January 14, 2014 at 15:01 - Reply

      Vabbè, tanto è di maglina… resta elastico comunque!

  2. carole January 13, 2014 at 11:27 - Reply

    SHEER BRILLIANCE so concise and informative a definate must read, have pinned and urged others to not miss this! Thank You

    • Mamma Nene January 14, 2014 at 15:01 - Reply

      Thanks Carole – you make me blush 🙂
      So happy you find it useful – and really overjoyed you pinned it (Pinterest = my addiction <3)
      Hugs from Italy

  3. Deby at So Sew Easy January 13, 2014 at 12:55 - Reply

    Everything I wanted to know about bias all in one place. Really well written Irene, thank you.

    • Mamma Nene January 14, 2014 at 14:58 - Reply

      Thanks Deby 🙂
      Glad you find it useful – I’ve found so many people wondering why the heck they had to cut on bias that I decided to write something, just to have a blog post to point at everytime they ask it to me again… lazy girl….

  4. Monica Swift January 13, 2014 at 14:05 - Reply

    Thanks for this! i knew what bias meant, and that it was stretchier and drapier, but that’s about it. My first experience with ‘bias cut’ was when I took a shape profile test that recommended what styles were most flattering, and it said to avoid bias cut garments. ha! At least on the bottom half 😉

    • Mamma Nene January 14, 2014 at 14:56 - Reply

      Hi Monica – happy to see you here (I love your blog :))
      I can’t figure out why you shouldn’t wear bias cut garment on your bottom half… They usually give their best in 99% of figures…
      Thanks for your lovely comment <3

  5. Pam @Threading My Way January 17, 2014 at 13:04 - Reply

    You’ve explained this so well, Irene!!! Perfect for those new to sewing.

    • Mamma Nene January 17, 2014 at 15:09 - Reply

      Thanks Pam! I’m so happy to hear that from you – I love your instructions/tutorials because they’re easily understandable also from who, like me, haven’t English as native language! I’m always in doubt when I write something, that people around the world won’t think: “What????”, reading my explainations!

  6. Jill Flinton January 17, 2014 at 14:14 - Reply

    Thank yoy for providing such an educational item on the Thumping Thursday bloghop.

    • Mamma Nene January 17, 2014 at 15:10 - Reply

      Thank you Jill for spending some of your precious time reading my blog – I truly appreciate 🙂

  7. Karen Johnson January 19, 2014 at 16:57 - Reply

    Irene, I love your blog. I have pinned so many of your instructions and tutes. You are doing a great job and your English is very good. No problem with following your posts. Keep up the good work.

    • Mamma Nene January 19, 2014 at 20:33 - Reply

      Oh, Karen, thanks for your sweet words!
      You can’t even imagine how much I’m happy to hear that from you! I’m always in doubt about my english when I write a tutorial, that I end up changing a thousand time my phrases… until I’m satisfied or (more frequently) when time to post comes!!!
      Please go on pinning, you know that Pinterest is my addiction n°1 XD

  8. […] last week Bias: Definitive Essential Foolproof Guide post, today I want to go practical: how can I bias cut a rectangle, having only its […]

  9. Simple Nature Decor January 21, 2014 at 14:31 - Reply

    this is amazing, Just love this too, I loved the previous Trick, cant wait to see this next sewing, i will subscribe

    • Mamma Nene January 22, 2014 at 12:08 - Reply

      Hi Maria 🙂
      On friday I’m posting more about this topic (it’s the last bias post for a while, I promise!) – stay tuned 🙂

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