Lindsay asked me to blog about thread tracing, so I thought I’d give you a brief tutorial on the two types and when I use each one. Each has its own advantages and you can use them together or separately depending on your project.
Machine Thread Tracing is done to a muslin to mark the seam allowances, grain, darts, center front, center back, waist etc. This is so you can quickly sew up a muslin for fitting and easily see where the seams and garment lines fall. A thread traced muslin that is altered is picked apart and the muslin itself is used as the pattern. In machine tread tracing I like to use black thread and a really short stitch length, 13 or more per inch, and when sewing up the muslin I switch to red thread and a longer stitch length, 7-8 stitches per inch. I do this so it’s easy to pick apart the red stitches and not accidentally pick the black tracing stitches. One advantage of machine tread tracing the seam lines is that it calibrates the pattern seam allowances to your machine’s seam plate and you get a more precise fit than you would if you marked the seams with a pen, or made up your garment by cutting right from the tissue pattern.
Hint: Always mark the right side of the fabric because the fabric front and back looks the same in a thread traced muslin. The photo on the right shows the black thread tracing and the red construction stitching on Abby’s Ralph Rucci muslin.
Hand Thread Tracing; I do this right on the fashion fabric from the right side. Hand thread tracing is done with seam allowances removed from the tissue pattern; the tracing marks the seam lines, grain, darts, center front, center back, waist etc. Hand thread tracing can be used when you’re working with fabric blocks if you have a pattern to match or a fabric that ravels badly, like a boucle or the silk taffeta I used for this 2007 cocktail dress on the left.
I used hand tracing on the Ralph Rucci bodice lace because there was no other practical way to mark the seam lines and I needed to see what beads & sequins have to be removed from the seam allowances. A hand traced pattern piece block doesn’t need to be cut until you’re ready to sew it; I like to roll them up and set them aside until I need them. I use a sharps needle and take long running stitches with small bites to get a good outline. And I make sure to push the needle under to the wrong side of the fabric exactly at corners and intersection points to mark them precisely. The seam allowances are added on before the piece is cut and the tracing is removed right before sewing. The thread on the Ralph Rucci bodice lace is basting thread, which is cotton, thick, very soft, breaks easily and leaves no holes. I’ve also used silk thread tracing on silk fabric for the same reason.
Hint: on a hand thread traced pattern block the grain always needs to be thread traced on each piece because you’ll need to re-grain the piece before you cut it out. In the example above the grain also happened to be at center back so I didn’t need to thread trace a grain line.