What Is The Seam Allowance
A seam allowance is the area from where the needle penetrates the fabric to the edge of the fabric. Seam allowances can range from ¼" to as much as several inches. Your pattern or project will tell you want to use in the instructions.
Sewing an accurate seam allowance is essential to ensuring your work comes out right. When the seam allowance is small you can line up with the marking on your needle plate. What do you do when it extends out beyond that?
I've seen a lot of suggestions online including making marking with pen, duck tape, rubber-bands and much more. The easiest and least damaging thing I have found to use is scrap booking tape. It is low tack, inexpensive and comes in cute colors and prints.
To ensure an accurate measurement use your seam guide and measure over from where the needle goes down to measurement called for in the pattern or instructions. Place a piece of tape several inches long in the correct space. Make sure that you keep the tape straight while pressing it down. If you get off pull it up and adjust it.
This technique can also be used to make a guide for lining up decorative stitching or trim. Do you have tip for keeping an accurate seam allowance when it goes beyond the needle plate markings? I hope you'll share it below in the comments.