Use the Presser Foot as a Seam Guide. On some sewing machines, the distance from the needle to the right edge of the standard presser foot is one-quarter inch. Test yours by aligning the right edge of the fabric with the right edge of the foot and sew a test seam. If your seam width measures one-quarter inch, you're all set!
Adjust the Needle Position. If your machine has this feature, adjust the needle position one notch at a time and sew a seam each time, using your favorite method of alignment. When your seam allowance measures one-quarter inch exactly, make a note of the machine's settings (which are likely to be metric).
Use a Seam Guide. Many sewing machines come with an adjustable screw-in seam guide. Or you can make a guide. Draw a line on a piece of graph paper one-quarter inch from the edge. With the seam allowance on the right, place the paper under the presser foot, bring the needle down through the line and release the foot. Do not remove the needle. Build up several layers of masking tape on a flat surface; align the edges as you add each layer. Adhere this tape guide next to the needle, aligning the edge of the tape with the edge of the paper.
Test drive the seam guide to be sure the tape is straight by sewing through the line on the paper, with the edge of the paper against the guide. If your seam is on the pencil line, you made a perfect quarter-inch seam guide. If not, reposition the guide and try again until it's right. Test it on fabric, just to be sure! As you stitch, look at the fabric rather than the needle and run the raw edge against the ridge created by the tape.
Purchase a Quarter-inch Presser Foot. Ask your sewing machine dealer or quilt shop owner about a special presser foot for your sewing machine. Have your machine's make and model number ready.
Excerpted from Marti's Log Cabin ABCs book.
What About Metric?
Even though I've been told that some quilters who measure in metric prefer a 5 or 7.5 mm seam allowance to 6, which is closest to one-quarter inch, those are not options with From Marti Michell templates. You must sew a 6 mm seam to have the specific-size shapes fit together accurately.
The following information is excerpted from the Encyclopedia of Patchwork Blocks, Volume 3 published by Michell Marketing, Inc. ©1998 Martha G. Michell