Updated
June 01, 2015.
Quilters use a quarter inch seam allowance to join most quilt blocks and other quilting components. A few exceptions include paper pieced quilts, sewing a narrower or wider seam when you add binding to a quilt with borders, and the half inch seam allowances we use to make rag quilts.
Why is it Important to Sew an Accurate Quarter Inch Seam Allowance?
Sewing an accurate quarter inch seam allowance is essential.
If seam allowances are off, patchwork pieces will not match-up with each other properly when it's time to sew components together.
You might not notice a seam allowance that isn't quite right when you sew together batches of same-sized squares to make a quilt. If the seams are all the same width, patches will still align correctly. Incorrect spacing becomes a problem when sewing together patchwork units that have a different number of seams within their boundaries.
Set Up the Sewing Machine to Test the Seam Allowance
Let's set up the sewing machine to sew an exact quarter inch seam, the standard seam allowance used for quilts. Once you've mastered a quarter inch seam, your blocks will have units with sharp points and crisp corners, and they'll fit together perfectly when it's time to assemble the block or quilt.
Some patterns will tell you to sew a 'scant' quarter inch seam allowance (see page 5). When you see the term used, make the seam allowance about a pencil line's width narrower than 1/4".
You'll probably find that a scant seam is best for all patchwork, so it's important to test your seam allowance before you begin to sew.
Brush up on your rotary cutting skills and learn important pressing techniques before you begin.
Materials Required to Test a Seam Allowance
- Rotary cutter, mat and long rotary ruler
- Iron and ironing board
- Sewing machine with a quarter-inch presser foot; use the standard foot if you do not have a quarter-inch foot
- 2 light fabric strips, each 2" x 4"
- 1 dark fabric strip, 2" x 4"
Have extra fabric nearby in case you need more test strips.
