Welcome back to the trench coat series. In this second installment, I’ll cover my favorite part of any sewing project—the seam finishes. I knew from the start of my trench coat project that I wanted to experiment with a different way of finishing the seams. I’m pleased with the technique I finally chose. You, too, can use self-bound seams on any project where you want to flat-line the pieces rather than install a bagged lining, and on garments whose interiors will be highly visible, as on coats and jackets.

Initial Considerations

Choose seam allowances

Cut the pattern pieces from the outer fabric and lining. You can cut both layers with the same seam allowances. I used 5/8-inch-wide (16 mm) seam allowances. Alternatively, you can cut the lining layer only with a narrower, 1/4-inch-wide (6.0 mm) seam allowance to speed up the process.

Audition thread

Experiment on scrap fabric pieces to see which topstitching thread you prefer, how your fabrics handle being folded and pressed, and whether your desired seam allowance works with the curves of your pattern pieces. Note: If you’ll be sewing a lot of curves, try a narrow seam allowance to prevent puckering at the later stages.
This technique uses visible topstitching, so you’ll also want to experiment with the top thread. Using all-purpose thread will enable you to stitch from the lining side of your project, which makes the sewing easier. However, a heavyweight thread may be preferable when sewing heavy fabrics. I used the Heavy Duty line from Gütermann for a professional topstitching finish.

Sew fewer lining seams

If your pattern consists of many panels, combine some for the lining to minimize seams on which you’ll be applying this finish. For example, the pattern I’m using features an in-seam welt pocket, so…