Thursday, September 14, 2006

Precision Piecing - the beginning

I've added a picture to this post.

I thought I would give you some preliminary information to think about while you are waiting for the seam allowance tutorial. Remember, this is what works for me. If this isn't something you want to worry about then don't - there are no quilt police. Just skip this post and the next one. I'm hoping you'll decide to stick around because what I'm going to show you is so easy, natural and painless that you won't know how you managed without it.

All quilters know how to piece, unless they do nothing but appliqué. What many quilters don't know is how to do it precisely. Sometimes their points get chopped off and their seams don't come together where they should. Many quilters don't worry about this, and that is perfectly fine. Many worry about it a lot, struggle, do a lot of ripping, and can't figure out how to prevent it from happening over and over. This tutorial is for that latter group of piecers - the ones who worry.

There are three key elements at work here: (1) accurate cutting, (2) accurate stitching, and (3) careful pressing (not ironing!). We'll save accurate cutting for another day. Careful pressing I've already talked about in a prior post. The lesson for this week is accurate stitching.


Stitching accurately is totally dependent on a consistent, accurate seam allowance. (Notice I didn't say anything about a 1/4" seam allowance - are you shocked?) Once you master that you will seldom if ever need to pin a block together before stitching. You will hardly ever need to square up a block. Your blocks will always be the same size when finished, and that size will be exactly what the pattern says it should be, whether the pattern is from a book, a purchased pattern or magazine, or a pattern you designed yourself. You can master this without any special attachment - no 1/4" foot is required. I piece everything on my featherweight, and though I have two different quarter inch feet I hardly ever use them.

The key is to find the correct seam allowance that will make the finished block parts measure exactly what they are supposed to measure. Usually that will NOT be a true 1/4" seam. If you take a true 1/4" seam you probably have problems, at least now and then. There is a good reason for this - the thickness of the thread you use takes up a little bit of space, as does the turn of the cloth when the seam is pressed to the side. If you stitch with a true 1/4" seam, the turn of the cloth and thickness of the thread subtracts from the size of the finished piece rather than the seam allowance itself. This is especially true for rotary cut pieces, as rotary cut pieces to begin with tend to be a tiny bit smaller than pieces cut the old fashioned way with templates. I'm not sure why this is true, but it is. It probably has something to do with the thickness of the pencil line traced around the templates, and where one cuts on that pencil line. So the correct size seam will be a scant 1/4" - almost as small as a 3/16" seam. Exactly how scant depends on your machine, the way you press and the thread you use. All 50 wt. thread is not the same thickness - did you know that? Some threads such as Aurifil than be thinner than others such as Guttermann or Coats and Clark even though they are both 50 wt.

Stay tuned - I'm going to teach you how to find the exact scant 1/4" that is right for your machine, the way you press, and the thread you use. Then once you've determined the width for "your" seam allowance, I'll show you how easy it is to keep it exactly the width it should be from day to day, week to week and year to year (as long as you don't change machines and/or thread types).

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Gratitudes:

1. Morning meeting at work cancelled
2. Rain on my windshield.
3. Delightful people who work at our Starbucks
4. Colored printers and colored markers
5. Fat free half-and-half - an oxymoron if I've ever heard one!

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10 comments:

Linda_J said...

Good job, Patti!

Carol said...

You are awesome! I see instruction book writing in your future when you retire :)

Gail said...

Eagerly waiting.....

Darlene said...

I'll be waiting for the next section in the lesson - I'm really excited.

quiltpixie said...

ok, you've got my attention :-)

Libby said...

While I fall more into the 'Don't worry about it' category in as much as I don't rip and fret -- I'm anxious to learn better accuracy.

Sweet P said...

Great start to the lesson . . . I'm anxiously waiting for the next lesson.

I especially like the explanation about the thickness of the thread and the turn of the cloth. I've never heard that before. Plus, I've always had a sneaky suspicion that a rotary cut piece is a little small.

Beth said...

I see you're using your "wall" on a featherweight. I have a "wall" that isn't as fancy, mine came in just plain old white, but I hated having a "wall" sticking on my cute little 1947 machine! So, I forked out $12 at my local Featherweight store for a 1/4 foot, I love it! It has a "wall" built right onto the foot.

Beth

Judy said...

For exactly the reason you mentioned. I always tend to cut my rotary pieces with a sliver past the line. Plus I always sew with a scant 1/4 inch. It's all in the measuring, which I am sure you are going to say in the next installation!!

Thanks Patti!

Cascade Lily said...

Patti thanks for the tips/tutorial.

I got the 1/4" foot free with my Janome Excel. Great! Unfortunate part is that it doesn't actually stitch a quarter inch!!!! So I use a single piece of masking tape - I think I'll now build me a wall!