How to Trim Thread for Sewing Zippers

Trimming thread is an important part of sewing zippers. Loose threads can catch in zippers and jam them. To keep the zipper working smoothly, trim the threads before installing the zipper and after each sewing step. Trimming the threads works basically the same way whether you are sewing a centered or lapped zipper, but each type of zipper installation has different sewing steps. Check for loose threads again after the zipper installation is completed.

Difficulty: Easy

Instructions

Things You'll Need:

• Garment or fabric with zipper
• Scissors
• Wastebasket
• Sewing machine
• Thread
• Seam ripper

How to Trim Threads for Centered Zippers

1. Cut off any loose threads or thread ends from seams near the zipper opening.

2. Cut off any threads that have raveled from the edge of the fabric.

3. After basting the opening in the fabric, cut off the ends of the basting threads at the top and bottom of the opening on the inside of the fabric.

4. Cut off the ends of the basting threads at the top and bottom of the opening on the outside of the fabric.

5. Cut off the ends of the threads after sewing the zipper to the seam allowance.

6. After topstitching the zipper to the fabric, cut off the ends of the threads on the inside and outside of the fabric.

7. Pull off all loose threads after removing the basting stitches with a seam ripper. Cut any threads you can’t remove close to the fabric.

8. If you have shortened the zipper, cut off the ends of the threads from those stitches, as well as any loose threads from the zipper tape itself.

How to Trim Thread for Lapped Zippers

9. Cut off any loose threads or thread ends from seams near the zipper opening.

10. Cut off any threads that have raveled from the edge of the fabric.

11. After basting the opening in the fabric, cut off the ends of the basting threads at the top and bottom of the opening on the inside of the garment.

12. Cut off the ends of the basting threads at the top and bottom of the opening on the outside of the garment.

13. Cut off the ends of the threads after sewing the zipper to one side of the seam allowance.

14. Cut off the ends of the threads after sewing the flap near the zipper teeth.

15. Cut off the ends of the threads after topstitching the zipper to one side of the garment.

16. Pull off all loose threads after removing the basting stitches with a seam ripper. Cut any threads you can’t remove close to the fabric.

17. If you have shortened the zipper, cut off the ends of the threads from those stitches, as well as any loose threads from the zipper tape itself.

Tips & Warnings

• Remember that each time you sew, there are 4 thread ends to cut: one at each end of the seam on the inside of the fabric, and one at each end of the seam on the outside of the fabric.
• Sharp scissors used only for sewing works best for cutting thread. Paper quickly dulls scissors.
• Use caution with scissors, sewing machines and seam rippers.