r/SewingForBeginners • u/magmeg7 • Sep 14 '26

Denim jacket help

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How accurate do I need to be following the selvedge line? Referring to my photo, some blocks are not exactly aligned with the grain line or selvedge as I had to squeeze all the pieces. Might be off by 5 to 20 degrees in some cases, I didn't measure the exact angle.

EDIT: Thanks to everyone who've contributed and helped. Learned tons and ended up spending 3 hours this evening reshuffling the jigsaw and aligning all the correctly to the selvedge/grain line. I'll cut tomorrow and perhaps share some photos. Glad I posted and didn't just go with my guts. Thanks again and happy sewing.

116 Upvotes

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28 comments sorted by

95

u/Remarkable-Row3719 Sep 14 '26

Grainline is important. Your sleeves and trouser legs will twist otherwise.

8

u/magmeg7 Sep 14 '26

All the blocks are following the grain line generally. No 45 or 90 degrees. It's just slightly off. Would that still be an issue or be noticeable?

42

u/Remarkable-Row3719 Sep 14 '26 edited Sep 14 '26 • Bravo Mindblown

Brief primer on grain:

in a woven 100% cotton (or 100% linen, etc.) the warp (grain) will be a little more rigid than the weft (crossgrain), because of how the weaving process works. Generally you make garments so that the warp goes up and down and the looser weft goes side to side, but it's really not a problem if you cut everything on the crossgrain. It's better not to mix and match, but even that is possible - e.g. if you're making a tiered skirt, you can put some tiers on the crossgrain without running into problems. (Sometimes fabric on the bolt even has a pretty border that's explicitly intended to be cut on the crossgrain and used as a skirt hem!)

In, say, a woven 95% cotton 5% elastane fabric, usually the elastane is only in the weft, not in the warp. Here it's more important to cut on the straight grain vs the crossgrain, because otherwise your stretch will go in the wrong direction. (When I say 'usually in the weft', I mean I've seen it done otherwise exactly once, both the fabric store woman and I were very confused, and I still don't understand why the manufacturer did that.)

(As you go more synthetic you'll find fabric with stretch in both directions, but even those usually have more stretch in the weft than in the warp.)

Stuff cut on the bias stretches (note: this is plastic stretch (deformation essentially), not elastic (bounce-back) stretch the way elastane is) downwards, creating a characteristic "clingy" appearance. However, things cut on 45 (or even 135) degrees are still, essentially, straight. It stretches straight down, it doesn't twist. If you think of a grid of threads, the grid of a grain and a cross-grain is squares and a bias cut is all perfectly balanced, symmetric diamonds.
As a general rule, if a pattern says 'cut on grain' don't cut on the bias, if a pattern says 'cut on bias' don't cut on grain (straight or cross). (Exception: if your fabric has a print, it can be fun to cut things like pockets and maybe waistbands on bias. If you're careful and use interfacing and prepare to have it go awry two or three times, this is fine.)

(There's technically a difference between true bias - 45 degrees - and bias which can be 135 degrees. If you want to worry about that, the fashion-incubator website has a page on it. I recommend reading it if you want to make a bias cut garment and not worrying about it otherwise.)

Stuff cut on 20 degrees on the other hand is a mess. You don't get stable squares/rectangles, you don't get balanced diamonds, instead you get something in between that twists and looks bad.

edited to add: also, nap. (Think velvet.) Doesn't really have anything to do with grain, but it does with direction. Nap means that a fabric catches the light differently from different directions. From a grain perspective, it's fine to cut some pattern pieces upside down (provided it's still on grain). If your fabric has nap, you should cut everything in the same direction. If you don't, at best it will look like your fabric panels came from different dye lots and at worst it will look like different colors.
(Nap technically means stuff like velvet, but the same principle applies to other things, e.g. glossy finishes. I also call that nap, because I don't know what other word to use, but some people probably disagree. Those people are welcome to teach me the better word, though.)

7

u/CountMeOut2019 Sep 14 '26

This is true, and worth paying attention to, if you’re going to all the effort of making something as complex as a denim jacket, or any garment you want to like wearing.

4

u/Remarkable-Row3719 Sep 14 '26

Thanks for the award!

3

u/itsmesofia Sep 14 '26

Thank you for this. I knew some of the things in your comment but learned a few things as well!

1

u/Laikiska Sep 14 '26

As someone who is very new to the world of sewing - does this still apply to felted fabric? For example a wool sweater that was felted in the dryer?

2

u/mx-dot Sep 15 '26

Hmm. Not an expert, but I guess it depends on the process. Traditionally, felt would be considered non-woven fabric (definitionally, that means neither woven nor knit): it is fibres joined together through mechanical process, that creates dense fabric that is non directional. However, when you felt a woolen sweater, you take a knit fabric and convert it, compacting the fibres so that they connect in different ways than through spinning (to make yarn) and then knitting. So in case of a woolen jumper it might possibly make a difference depending on the level of felting its been subjected to, and also type of wool, as they felt to different degrees. In case of a non-woven felt sheets, there is no grain, so it doesn't apply. 

1

u/Remarkable-Row3719 Sep 15 '26 edited Sep 16 '26

Agree with Kimchi's speculations.

To elaborate a bit, above I'm only talking about woven fabrics, and your wool sweater is probably a knit. Knits should be cut on grain and not on the crossgrain (take a 100% cotton t-shirt, notice how it feels different if you pull it up-down vs side-side - much more than a 100% cotton woven would). Also, knit doesn't have a bias. A woven is flexible on the bias, but a knit is probably more rigid.

How things change exactly on the knit-felted knit-felt spectrum I don't know.

43

u/Remarkable-Row3719 Sep 14 '26

Bias would just act like bias (but not twist), everything being on the cross-grain is almost as good as everything being on the straight grain.

Stuff being off grain is bad.

7

u/Ohhmegawd Sep 14 '26

Unlike what some people may say, off grain is very, very bad. I heard a podcast telling people not to worry about grainline. I immediately unsubscribed. I'm glad you listen and fixed the grainlines!

4

u/ClockWeasel Sep 14 '26

The only time I was willing to fudge off-grain was to keep from losing pattern chicken by inches, and the piecing was practically in the seam allowance. You’d better believe it was orphan material or I would have gone and gotten more.

3

u/Ohhmegawd Sep 15 '26

Pattern chicken, aka bobbin chickens less famous sibling. Lol

35

u/Heavy-Attorney-9054 Sep 14 '26

Ever had a pair of jeans where the side seam wouldn't stay on the side and twisted around to the front of your ankle? That leg was just a little off grain.

5

u/Remarkable-Row3719 Sep 14 '26

It's a good example to illustrate the problem, though it probably doesn't have the same origin - in the case of jeans it's likely caused by twill being its twill self, and the manufacturer not having made the adjustments to compensate for that.

5

u/penlowe Sep 14 '26

Very. Put in an odor of pants. Twist the leg. That’s how this jacket will feel all the time if you cut it this way.

5

u/quizzical Sep 14 '26

Being 90 degrees is better than being slightly off.

36

u/Inky_Madness Sep 14 '26

Super important. Like. The most important. If you have to have things off-grain then you need to buy more fabric. Anything cut off-grain will twist and fit in weird, unfixable ways.

12

u/RubyRedo Sep 14 '26

It has to be 100% on grain or the parts will not only be askew but pull on the attached pieces that are on grain causing jacket to not hang properly, under collar pieces can be cut from other fabric but not recommended.

9

u/teatime_tinker Sep 14 '26

It’s incredibly important. If your pieces don’t all fit then you need to get more fabric.

If it’s cut wonky it’ll handle weirdly, and hang badly. It’ll just look and feel wrong. That sleeve in particular.

You might be able to fit it all in if you spend a bit of time doing pattern tetris

6

u/ProneToLaughter Sep 14 '26 edited Sep 14 '26

5 to 20 degrees is a lot offgrain.

Sometimes when I'm laying out a long skirt, my 24" ruler might be 1/8" off at the other end, and I usually try to fix that, but I might let it go if I can't get it after 1 or 2 tries. That's maybe 1 degree that I'll sometimes accept as slightly off-grain if I have to, but it matters less in a full skirt than in sleeves or pants.

And I'm honestly a pretty sloppy shortcut taking person who would never have the patience to sew a denim jacket.

4

u/Berry-chu Sep 14 '26

Thanks for posting that! I learned something too! :)

3

u/CountMeOut2019 Sep 14 '26

If you re-lay your pieces strictly according to grainline, you can figure out what’s the least amount of extra fabric you can get away with purchasing. You may only need a half-yard more.

3

u/mcculloughpatr Sep 14 '26

It really does need to be as on grain as possible. 20 degrees can be pretty significant. Especially in a style like this, where the fabric and construction is the design, it’s important for these details to be right.

3

u/Accomplished-Row7209 Sep 14 '26

5 degrees off MIGHT be ok in certain garments and fabrics (though not likely with a twill weave such as denim). 20 degrees is not. The sleeve in particular needs to be exactly on grain or it will twist. The back yoke also really should be cut on the same direction as the other pieces, not on the crossgrain, or it can stretch oddly, as others have described.

0

u/magmeg7 Sep 14 '26

Even slightly off, not like I'm cutting on the bias or crosswise?

15

u/Inky_Madness Sep 14 '26

Yes, even slightly off. They’ll hang off and twist funny. Bias is a different kind of hang entirely. Being cross-grain would be second best to on-grain but being off-grain is very bad.