Friday, October 12, 2007

The Seam Allowance

The current Name That Quilt standings:

Ice and Fire -- 3
Star Halos -- 3
Saturn's Night Sky -- 1
Refraction #4 -- 1
Evening Star -- 1

If you haven't voted, check in here and throw in your two cents worth. Polls close next weekend.

Don't know what I'm talking about? Check here.

Or, if you would like to help me come up with a good symbol....

I'm soliciting ideas related to another quilt project at my other blog, here.

The Passion and Intrigue of the Seam Allowance

It seems like most of the people reading SOtC at this point are quilters themselves. Originally, most of the readers were non-quilters, and I was trying to explain the basics of the craft to them. Did anybody actually read these introductions to someone else's hobby? Who knows. But today, in the original spirit of the blog, I present this fascinating discussion of the Seam Allowance.

To start with: You don't want to think too hard about the details of how a sewing machine works. You just don't. It's hard to figure out, and it doesn't seem like it should actually work, and you'll forget it almost immediately, and just have to work it out again next time you get curious. Basically, though, you've got two threads -- the top thread and the bobbin thread -- that interlock at every stitch through the two (or more) layers of fabric that you are sewing together.

Now, the weave of the fabric is what holds the threads in place. Because of that, you don't want your stitches to be right next to the cut edge of your fabric. If the stitch is too close to the edge, the fabric will unravel in no time, and your seam will come undone.

In quilt-making, there is a nearly universal standard distance between the edge of any piece of fabric and the stiching used to piece it. That distance, called the "seam allowance," is one quarter of an inch.

In designing quilts and cutting fabrics, it's really critical to remember your seam allowance. If you want your quilt to consist of 5" squares, you have to cut 5 1/2" squares -- 5" plus 1/4" on all sides. If you want to alternate between 9" squares and little 3 x 3 checkerboards of 3" squares, you need to cut 9 1/2" and 3 1/2" squares. (If you are going to cut a triangle, or anything else that isn't rectangular, it gets more complicated. You'll be doing some applied geometry.)

When you are -- to use my very least favorite quilt term -- "fussycutting," or cutting a specific piece to make it ~exactly right~ for where that piece is going in the quilt, you have to think about the seam allowance. Anything on the outer 1/4" is going to disappear; it gets pressed, or literally folded, under the quilt face.

Here are some two inch squares from the Oregon Map Quilt, before pieceing. Keep an eye on that one three across and three down. See how much yellow it has in it? We don't like that. But we're not worried. Also, notice the square on the lower left, the one with purple grapes all around its edges.

Here are the same squares sewn into strips. Now they are 1 1/2 inches wide. Much of the yellow in three across, three down is folded underneath now.

And here are the same squares in the final product, with the strips sewn together. The yellow is gone. And there's just a couple of grapes left (representing LaGrande, actually) in the fabric that was on the lower left. The rest of the purple is safely out of sight, hidden in the seam allowance.

When I started this post, I made myself the challenge of trying to write about seam allowances in a way that would be accessible and interesting to the non-quilter. And I see that I've failed miserably. Ah, well.

See ya next week!


Rebel said...

OMG - I'm really impressed with how well your corners match up considering how small the squares are. And tell me you did not.... you did NOT quilt the outline of each county in Oregon!

I don't think I'm worthy to read this blog anymore.... seriously - don't look too closely at any of my quilts!!! I have a very 'free' relationship with seam allowances. ;)

Rebel said...

There are cows in Tillamook! There are COWS in Tillamook.

This quilt is awesome.

mrs. 5000 said...

As a non-quilter, I'd like to say I'm enthralled with the topic of seam allowances! Of course, I know what's good for me.

One more vote for Ice and Fire, si vous plait.

Michael5000 said...

@rebel: Oh, my corners match up. It is my way. And really slender, sharp pins are the, um, path. The path of the way.

I'm afraid I can't tell you I did not quilt the outline of each county in Oregon. For that would be a lie. But there's only 36 of them.

And: you're more than worthy, you big silly.

@Mrs.5000: You always say the sweetest things.

gl. said...

i actually really liked this post, but it's one of the reasons i'll never get into quilting: the seam allowances would drive me insane.

Michael5000 said...

I've been told to add one vote for "Ice & Fire" for Mom5000.

Dad5000 threw his vote away on a write-in candidate.