It’s important to measure and pin carefully when hemming a garment. Instead of working with a ruler or seam gauge, use your sewing machine to help you do the job accurately.
First, serge the hem allowance edge. Then remove the machine’s presser foot and lower the needle. Measure from the needle to the right, the desired hem allowance width. Mark this position with tape, parallel to the seam guide lines on the machine’s stitch plate.
Place the garment on the machine, wrong side up, with its hem allowance toward the tape mark. Fold the allowance to the left, so its finished edge is just below the needle, and the hem fold is aligned with the tape. Pin, slide the garment back a few inches, and repeat to complete the hem pinning.
Reader tip sent in by Mary Duncan, Oklahoma City, Oklahoma, and first published in Threads #160, April/May 2012.
Once the hem is properly pinned, Insiders can learn an efficient and professional way to sew it, in “Blind Hems by Machine.”
It's a lot easier to cut a piece of card double the depth of your hem, cut a notch at the right depth and then fold to the notch and pin at the required intervals. Fabric draped over you sewing machine is quite likely to distort.