Perfecting the Quarter Inch Seam

We Carry
by Sara Snuggerud in Archives

What type of quilt PIECER have you become? Are you:

  1. “Fast-and-speedy-hurry-up-and-get-it-done-and-on-to-the-next-project” piecer.
  2. “I-take-my-time-and-enjoy-every-part-of-the-quilting-process” piecer.
  3. “Every-point-must-be-perfect-and-if-it-is-not-it-gets-ripped out” piecer.

No matter what your quilting style, everyone is after THEIR own perfect 1/4” seam. I say “their”, because each person holds the fabric a little different, sews on a different machine, watches a different guide, or has one of many specialty made quarter inch feet. Even rotary cutters, rulers, and pressing techniques can alter the “perfect” 1/4”.

It was a great day when sewing machine manufactures began making the Quarter Inch foot for quilters. Quarter Inch feet are made exactly 1/4” wide. When sewing two pieces together, if any fabric can be seen sneaking out along the right edge of the foot, the seam will be too deep. Sewing this way will be the most problematic when triangles or angles are involved. If a pattern only uses strips, squares or rectangles the 1/4” seam is not as critical. Using a consistent seam allowance guarantees this quilt pattern turns out flat.  This is where “Type A” or production quilters shine!

Do you know what happens when the seam is pressed? Part of the seam allowance is used up ever so slightly in the fold of the fabric. On a block with lots of strips, such as a log cabin block, this small amount of lost of seam allowance quickly adds up, shrinking blocks by 1/4” – 1/2”. This is why we hear we should use a “SCANT 1/4”. (I almost wish they would just make us a “Scant 1/4” foot, but they don’t).

To allow for that hair’s-breadth seam size that gets lost in the pressing, it is best to use a slightly-smaller-than-a-quarter-inch seam allowance. Once you figure out on your machine where to guide the fabric for a scant 1/4” you will be in heaven! Corners match up and angels sing! Blocks fit together and a ray of sunlight shines directly on you and your sewing machine! “Type B” quilters, you are here.

If you not getting the results you want and are ready to take your quilt piecing to the next level, it’s time to test your piecing techniques. Begin by cutting precise strips or blocks with new or freshly sharpened rotary cutter blades from Heirloom Creations sharpening service. Use a new accurate ruler with THIN LINES. (Click here to read Sara’s tip on “When to Replace Rulers”.) Sew the strips together with your Quarter Inch foot, press carefully, and measure the finished size. (See Pressing vs. Ironing)  If the block is the exact size, then Congratulations – you have mastered your 1/4” seam allowance! If you find the block on the skimpy side, rotary cut another block and try ONE (not all!) of the following adjustments.  For “Type C” quilters, this may be your salvation.

  1. Guide the fabric slightly closer to the needle, in slightly from the edge of the Quarter Inch foot.
  2. If you are not using a Quarter Inch foot, locate one at your local sewing machine store.
  3. Adjust the needle position one position to the right. This is an option ONLY on machines with MORE than five needle positions. Check by turning the hand wheel that the needle does not hit the foot.
  4. If your Quarter Inch foot does not have a guide, place an adjustable seam guide on the machine and next to the very edge of the foot. Check the manual for proper attachment of the seam guide, and if one came standard with the machine.

After mastering your 1/4” seam allowance, and if some blocks have shrunk slightly, and no amount of pressing will flatten them any further, then here is the answer. When the sides do not match exactly in length, begin by pinning at the beginning and end of the side to be sewn. Place the block/fabric with the excess fabric next to the feed dogs of the sewing machine. The feed dogs will help ease the excess length into the seam. Gently hold onto the pin at the end of the block and apply extra resistance if necessary. Use this method for sewing sashing and borders as well to square up the quilt.

Once I mastered the 1/4” seam allowance on my personal sewing machine, the finished blocks measured their proper size: 12 1/2”, 6 1/2”, 4 1/2” etc. With these accurate finished block sizes sewing the pieced blocks together was much simpler. I no longer had to fight with different length blocks to make them fit. Since they were all the same size, the quilt assembly continued smoothly.  No matter what type of PIECER you are, getting the correct finished size block on the first try is quilter’s heaven!

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