Why cut on the straight of the grain

Sounds simple doesn't it.  And you always hear it, but why?  Why is the "straight" so darned important.

First what is the straight.  When you go to the fabric store and they roll off 3 or 4 yards of fabric for you, the lengthwise grain or the grain that is the full length (the side they measure the fabric on) is the lengthwise grain of the fabric.  This is called the warp weave.

The widthwise grain or the grain exactly perpendicular or at a 90° angle from the lengthwise is the woof weave.

So when the fabric is made on the loom, the lengthwise yarms or threads are laid out the full length of the bolt - usually 25, 50 or so yards, depending upon the mill, loom and use of the fabric.

 

The long warp threads have to be very strong as they have to withstand the process of looming the whole piece.  If even one falls apart, then the whole bolt is lost or damaged.  While the woof weave just has to be shuttled back and forth through the warp weaves alternately, it doesn't have to be that strong.

So when you get ready to cut out your fabric from your pattern pieces, and each piece has the lengthwise grain marked, this is why it is so important. 

 

The up and down (lengthwise) direction of each pattern piece takes the brunt of stress during the lifetime of the garment...you wear it in this direction, you hang and store it in this direction so it's logical that this is the direction you want the stress of the fabric to be the strongest. 

When you sew on the bias (or the diagonal of the weave of the fabric) or with the woof weave on the lengthwise grain of the fabric, the fabric will spring or loosen and usually not in a regular way.  This can cause hems to look uneven (actually they are uneven).

Additionally this can cause an actual size change in the garment as it ages.  As the garment relaxes under the pressure of gravity (without the strength of the lengthwise yarn to hold it in shape), the garment will become longer and thinner.  For an outfit that either you made and love or took a long time to accomplish and enjoy wearing to change shape is heart-breaking.  You can re-block it, but it will only warp out of shape again and again. 

So stay on the lengthwise.  Then comes the concept of "turning".  This is cutting one piece going up and the other going down.  I'm not a proponent of this cause just the slightest, tiniest nap and poof, you look like the court jester.

And it wasn't intentional!

So I rarely if ever turn.  The best for guaranteed great results is to always cut on the lengthwise of the grain and without turning.

Comments

[Trudy Callan]

This explanation was very helpful. Thanks so much for clearing they whys up for us.

Trudy
www.sewingwithtrudy.blogspot.com

[Bunny]

I cut everything "with nap" too. We have both probably learned the hard way!

[Handmade]

Nice explanation - but we call the woof the weft!!

[ClaireOKC]

@ Handmade...oh I know. I forget - that is the other name....both are used, but I guess it was woof I heard first so that's the one I use, and either is right! Tomatoes, tomahtoes, potatoes, potahtoes....
;)