August 2, 2009

Fabric: Grains and Cutting

I remember my mom trying to explain the grains of fabric when I was first learning to sew. Of course, a 6 year-old couldn't have cared less what "warp", "weft", and "bias" meant. All I heard was "blah, blah, blah, look at all the big words I know!". :o)

But it's simple, really! And sometimes can be very helpful to understand. Fabric is woven with a bajillion little tic-tac-toe threads, running across each other.
  • "Warp", or "lengthwise grain", is just the name of the threads in the fabric that run up and down, alongside the selvage (another scary word, which is just the white part at the edge of the fabric, usually with the brand on it).
  • "Weft", or "crosswise grain" are the threads that run perpendicular to the warp threads
  • "Bias" is the term for the where the threads meet diagonally.

This can come in handy to know, because all fabrics, even non-stretchy ones, stretch a little bit.
This pink fabric is just a plain cotton, and when I stretch the warp threads (photo 1), there isn't really any stretch at all. When I apply the same stretching to the weft threads, there is a little give (photo 2), but when I stretch it on the bias, it's very stretchy! Sometimes you want a little stretch in the piece you're cutting, and sometimes you don't. For example; when making bias tape, you want to cut on the bias, for optimum stretchiness, since it will be stretching around the corners of a garment! :o)



Now-about cutting!
The first thing you want to do with your fabric is even up the top and bottom. They can't always cut fabric perfectly straight at the store, so it's important to make sure you've got a straight line when you get home!

Start by holding your fabric up, folded in half, with the selvage edges(that's that white line, remember?) matching up on the side. That should tell you if your top and bottom sides are straight or not. In the first photo, you can see that when the selvages don't match correctly, the fold of the fabric is billowy. In the second photo, I've matched the selvages correctly, so the fold lies flat. (you don't need a toddler with a book for this, but she thought it added a little something)

The fabric store cutter did fairly well, but it's clear here that I'll need to smooth out the edge a little:

Using a rotary mat and ruler, match up the top of the ruler with the selvaged edge to make sure that it will be an even cut. You can also use your pattern as a guide, if your fabric has one.
Notice that the ruler is flush with the selvage, and the row of hearts, but the edge that I cut off is uneven.
As you move the ruler down, use a couple of inches of the section you've already cut as a guide to keep the ruler straight.


Once you're all straightened up, you're ready to cut your piece! I always like to cut my pieces on the fold, if they're the same shape on both sides. For example, for this 5"x10" rectangle, I folded my fabric, and cut a 5"x5" square. When opened up, it's the right size!
(when using this method, fold over just the length you need from the edge, to avoid having a big hole in the middle of your fabric!)


If you don't have a rotary mat, cutter, and ruler, sell your car and buy one with the profit.
If that's not an option, you can try this!

Your fabric store should have something called quilter's chalk, or tailor's chalk. This comes in several different forms, but it usually only a few dollars. I've also heard that you can use white charcoal pencil in a pinch, which I had on hand!
It's very handy for marking out things before you cut them, which is a great way to ensure a straight line, when all you have are scissors to work with!

Cutting the same 5"x10" rectangle, use a tape measurer to measure 5" from the raw edge, and mark it at the fold:


Then, measure again, about 5" down. (my picture shows ten inches down, because I am silly, and forgot I was cutting on a fold), and mark a straight line along the tape measurer. Then use your tape measurer to draw a straight line between the two marks. Then cut along your lines!


If you make a mistake, you can use a scrap of batting to brush it lightly, "erasing" the chalk.

P.S. If you can only buy one of the rotary tools, the ruler would be nice to get first! It would be much easier to use than a tape measurer :o)

I hope that helps!
It's a little bit of a pain to do the extra step of chalking, but your lines will be so much prettier.
Good luck!

22 comments:

  1. I hate matching up the edges with a new cut of fabric (it's what deters me from getting started on projects actually) but your way seems much better than mine. I think I was doing it the dummy way! Thanks for this tutorial too, it's nice to get all of those terms straight and know what it's all about.

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  2. Wow, you are thorough! I probably would have just torn it to find the grain... hehe. I go for the quick and dirty method!

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  3. I feel silly that I never quite understood why bias tape needed to be cut diagonally. Now that you mention the stretchiness factor I totally get it. Duh. Thanks for posting this. I don't consider myself an expert sewist by any means, but I've been doing it for awhile. You'd think I would have figured this out by now! :P

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  4. I can´t belive that you have done this for us!!!!!!!!!!!!
    It is the best explanation ever.
    Disney, realy, you can NEVER imagine howw thankfull I am to you for this.
    If you lived near me I would go over and give you a huge kiss... and a present!! ;)

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  5. Thanks for the lessons! I am learning so much. Does it matter what size rotary cutter you get? I was going to buy one online but got too confused by all the options!

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  6. Nice tutorial and explanation of warp, weft, and bias. Thanks!

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  7. fantastic tutorial, thank you! Very clear and concise. I agree that a ruler is a definite must have, I don't know how I managed without one!!

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  8. Thank you sooo much. i always just left my fabrics wrinkly and uneven when i cut the pieces.....seems perhaps i should take a bit more time lol. Is it really soooo important which way you put the pieces on the fabric?? I am sooo liking these tutorials

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  9. Joann's had their rotary cutters and rulers 40% off this week. I just bought mine and am in love! Can't believe I've been sewing for years without these handy tools. Thanks for the tutorials.

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  10. Lovely and simple explanation of warp, weft and bias. Thanks :)
    I'm unclear why we want to even up the edges of our raw fabric? Does that make a difference somewhere? It just seems like extra cutting to me.

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  11. Thank you for the great tutorial!

    I have silly ways of remembering warp from weft, and for bias and selvage.

    I think of "warp speed" in a science fiction movie like Star Trek -- they always shoot forward, or "straight ahead", when they go into "warp" speed.

    And for weft, I think of turning to the wight or the weft, turning to the left -- across the fabric, not straight ahead.


    When we have a bias toward or against something, we are usually mentally "leaning" toward it or away from it.

    The selvage is what we "save" from the "edge".

    Cheesy, I know, but works for me. Maybe it will for someone else, too. :-)

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  12. I'm so glad you are sharing this information! Can't wait to learn more. My mom tried to explain the whole bias strecth thing and I'm 26 and it still was blah blah blah! Thanks again!!

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  13. I just starting sewing recently and this really helped. Thanks for the great explanation!

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  14. PERFECT. This is exactly what I needed. I think I was one of the ones that specifically asked for this "sew basic" and you came through for me a million times over. WONDERFUL! Thanks so much for doing this.

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  15. Thank you for writing this and sharing all the great pictures. I've always understood there was a difference, but this brought it to light in a very clear way. Sometimes I get overwhelmed reading a book about it. (I LOVE pictures!)

    Thanks again!

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  16. I absolutely love your tutorials. I use old bar soap to mark my fabric. It's cheap and you can easily rub it off the fabric.

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  17. Greetings from Chicago! I'm enjoying your blog more than I can say in a simple comment. As someone who's trying to learn how to sew the hard way, I've found innumerable tips here that I've not yet read anywhere else. Thanks!

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  18. Thank you for these clear instructions. I have always skipped this step out of laziness/fear. no more! x

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  19. A plain school ruler, with a flat bottom works well in a pinch for short increments or a yard stick. Easier than a tape measure and usually on hand. Sorry if this is a repeat.

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  20. Thank you so much for this tutorial using the cutting mat, cutter and ruler - I can't wait till church is over today so I can rush other to a store and get them!!! I'm a new sewing machine owner (even though I've known how to sew from the ages of blah, blah, blah! LOL!!), and trying to gather the basics. I figured that the mat, cutter, and ruler were used for this purpose, but I think I was intimated by then. Not anymore! Thanks so much for your great website and great tutorials! I made a ruffled tote last night and am IN LOVE with it!

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  21. Thank you so much for this post. I've learned so much and I want to thank you for sharing <:

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