The Quilting Seam Allowance

How important is a quarter inch quilting seam allowance to any quilt project?

An accurate ¼” seam allowance is so important to the success of your project.

Do you have machine pieced quilt blocks that are not the right size?

There are solutions! Even for the beginner.

Spend a little time and effort to master the accurate ¼” quilting seam allowance. It is an important basic for the beginner to the quilt making success. You will add perfection to your points and pride to your quilting projects.

Have you ever experienced the shrinking log cabin syndrome in your quilting project? It happens when you know you cut 2” strips for your quilt blocks and yet they don’t end up to be the proper size.

Or have you ever been in on a quilt block exchange only to be disappointed by the quilt blocks you received? Maybe the unfinished quilt blocks actually measured several different sizes. So you struggled to set them together in a quilt top - or maybe you were unable to use them all in a quilt project because of the quilting seam allowance.

If you have experienced these frustrations, then you know that an accurate quarter inch quilting seam - as basic as it seems - is vital to the success of your quilt. Even when using an accurate quilt pattern, quilt blocks can vary in their finished measurements because of slight variations in each quilter’s interpretation of the standard quarter inch quilting seam allowance. Why not test yourself with these short questions to see where your quilt blocks may be coming up short.

True or False?

1. If I draw the quilting seam line on my quilt pattern pieces and stitch on it, cutting an even quarter inch quilting seam allowance is not important.

TRUE. This is the technique used by hand piecers. Hand-piecing templates have no cutting lines, only sewing lines. To use this method, trace the sewing line on the wrong side of the fabric. Cut the pieces out, eyeballing as approximate ¼” seam allowance around each piece. Pin the pieces together, matching the beginning and the end of each seam. As long as the seamline is accurate, the quilting seam allowance does not have to be exact.

2. As long as my quilting seam allowance is consistent (for example: always using the width of my pressure foot), the quilt block measurement will work out okay.

FALSE. (unless you have a special ¼” presser foot). This is a common misconception because it can work some of the time.

For example, if you are making a Nine Patch quilt pattern from 9 ½” blocks, all of the blocks will be the same size. Even if they do not measure 9 ½”, they will fit together in a quilt.

However, when you use a pattern for a quilt block that has a different number of seams in each row, you will be very frustrated. Let’s assume that your present presser foot is actually 3/8” wide. This means that in each quilt seam allowance you stitch, two additional 1/8” widths are removed from the finished pattern piece. That’s a total of ¼” per seam. If there are five seams in one row of a block, the row will be 1 ¼” too short. Stitching these two rows together may be impossible because there is a ¾” difference in their lengths.

One disadvantage of the method is that you will be unable to use many of the quick strip piecing techniques.

Even slight differences count. A presser foot seam allowance only 1/16” wider than it should be will yield a five seam quilt block that is 5/8” smaller than the planned size and that’s still too much.

Accuracy problems can occur if you take a beginner quilting class and start your quilt blocks on a different machine. The two sets of quilt blocks may measure differently because of the differences in presser feet. Even If you have drawn accurate templates or cut pieces accurately, relying on an inaccurate pressure foot as a seam guide will cause problems in easy machine piecing.

3. I can use my sewing machine to dial a needle position which is the correct distance from my pressure foot edge in order to use it as a quilting seam guide.

TRUE: (if your machine has an adjustable needle feature). This is probably the most accurate method. Check your manual or contact your sewing machine dealer to learn the correct setting for the presser foot you use most often.

If this isn’t possible, check ¼” graph paper for accuracy and cut along one of the dark lines. Align the cut edge with the outside edge of the presser foot and the rest of the paper positioned under the needle. Lower the presser foot, move the needle and test each needle position, sewing a few stitches to see which setting hits right on the line ¼” from the cut edge. This technique allows you to do easy machine strip piecing and quick half square triangles with no marking. You must remember the setting and that it is accurate only with that pressure foot.

Many older machines do not have a needle position feature. Do not despair - read on!

4. I can get an accurate seam by using masking tape or another seam guide to measure ¼” from my sewing machine needle.

TRUE: Cut ¼” graph paper. Place the line directly under the needle and lower the presser foot. Sew along the ling for a few inches to ensure that the paper is in a straight line.

Now place a strip of masking tape right up against the cut edge of the paper, front to back and just ahead of the presser foot. To verify accuracy, use the tape as a guide, sew a seam on strips of scrap fabric and measure the width of the seam.

5. I can use an accurate ¼” wide pressure foot to judge my seam allowances.

TRUE: There are several feet available for sewing machines of every make and model and they help a quilter achieve accurate quilting seam allowances.

Finally, since we may all judge the term “edge” differently, it is wise to test the accuracy of your seams. Cut three 2” strips, sew them together, and press. Now measure the finished width of the pieced strips. It should be exactly 5” wide.

Your machine needle is another factor to consider when you measure seam allowance from the needle. Do not change the size of your machine needle in the middle of a quilting project. There is a very small difference is size, but it can effect the accuracy of your quilting project. If you break a needle, use the same size to replace it and recheck the seam allowance. You may need to reposition your needle setting or seam guide slightly. The quilting seam allowance is another important part in basic quilting instructions.

Go to Basic Quilting Instructions from Quilting Seam Allowance
Go to Ideas-for-Quilting Home Page from Quilting Seam Allowance