Mini Sewing Tutorial: ​How To Finish An Armhole Edge With Decorative Trim

A decorative trim finish works best if used with low fraying or no-fray fabrics that maintain enough strength and stability along their cut edges. Given that the trim hides the armhole's raw edge as opposed to enclose it, the fabric itself has to maintain enough structure and durability on its own.

1. Once the garment's shoulder and side seams have been stitched and clean-finished, apply a straight stitch along the armhole edge at about 1/4" away from the fabric's raw edge. Applying this stitch from the garment's wrong side will provide more comfort during the application process.

​This stabilizing stitch is called staystitching and will play an important functional role in preventing the armhole edges from losing their durability and stretching out of shape during both the construction process and the garment's life cycle. 

2. Working on the garment's right side (as shown above), fold one of the trim ends inward at about 1/2" or 1/4", and align the folded edge with the garment's underarm seam. In this alignment, the body of the trim should fully cover the armhole's raw edge. Insert a pin perpendicularly to secure all layers together.

3. Continue aligning and pining the trim to the armhole's raw edge, ensuring that the trim fully covers the edge throughout. 

4. When arriving back at the underarm seam, leave some excess trim that extends about 1/2" past the seam, and fold this excess inward, aligning the resulting fold with the garment's seam. This folded edge should abut the trim's initial folded end. Insert a pin perpendicularly to secure the layers. 

Note: It is highly recommended that you hand baste the decorative trim accurately in this position as doing so will prevent it from shifting out of alignment during the machine stitching process. 

5. If your trim can be machine stitched, topstitch it from the a garment's right side, following one of the trim's edges or linear structures as a guide. 

6. Once fully stitched, use a seam ripper to remove any temporary hand basting. To seal the trim's folded ends at the underarm, slipstitch them together by hand using matching color thread for an invisible application, 

If the trim cannot be machine stitched, attach it by hand using either a prickstitch application or a blind stitch like slipstitching or a hemming stitch. Your technique should be chosen based on your trim and what will provide the strongest and least visible connection. In the example pictured above, a prickstitch is used to attach the decorative trim from its face side.