What Type of Thread is Best for Sewing on Leather?

I am constantly asked what type of thread works best when sewing leather on a standard sewing machine. It surprises me because I really haven’t had too much of an issue with thread during the years I’ve been sewing leather. I did learn early on to avoid 100% cotton thread, as it had a tendency to fray, but other than that I haven't given it much thought. However, last week I didn’t have a specific color of thread and ended up pulling out some Rayon thread and using it on leather. My results definitely got me to thinking.

When I started researching what was “recommended” in publications and online I wasn’t too surprised by what I found. Professional publications recommended using Nylon thread and people who actually sewed on leather for a living recommended a poly/cotton blend.

Unsatisfied with the varied response I came across, I pulled out one spool of each different kind of thread I could find in my sewing room and tested them. I used a size 14 leather needle and ran a 2 foot seam through two layers of 3.5 ounce leather with each thread type.

I left my experiment with the feeling that you can use almost any kind of thread other than Nylon, Wool, or Metallic. I broke my finding down into the following table for you. The further down the ranking a thread is the more you will have to “work” with it to get the results you want; but numbers 1-6 do work. If you are on a budget and don’t happen to have Rayon in your sewing stash, use a standard Dual Duty (poly/cotton) blend; it is strong and sews nicely. The thread I found easiest to sew with was Rayon.

My Results

  1. Rayon: Even stitches. No fraying, breaking, or skipped stitches. Hard to break.
  2. Dual Duty (37% cotton/63% polyester): Nice even seams. No pulling, tugging, or fraying of thread. Hard to break.
  3. Quilting (32% cotton/68% polyester): No pulling, tugging, or fraying of thread. Slightly more sensitive to enlarging or reducing stitch length. Slightly easier to break.
  4. Cotton: Nice even spaced seams. No pulling, tugging, or fraying of thread. Did have a slight frayed look to end of thread going through needle. Slightly easier to break.
  5. Silk: Did not fray or break during use. Enlarged or reduced stitch length on it’s own. Hard to break.
  6. Polyester: Did not fray or break during use. Enlarged or reduced stitch length on its own. Slightly easier to break.
  7. Nylon: Frayed constantly against sewing needle. Had to rethread every 6-8 inches. Slightly easier to break.
  8. Wool: Nice evenly spaced seams. Took over 6 feet of seam before I was able to get a clean seam. Even then it tended to knot up and give me issues. Broke easily.
  9. Sulky: Even spaced seams (when it would make them). Broke every 3 inches. Frayed thread badly. Broke easily.
  10. Metallic: Knotted, frayed, and broke constantly. Could not even get 2 inches of seam. Broke easily.

About the Author

Misty Marquardt is the designer and owner of Make Them Yourself patterns. She has over 20 years experience sewing with all fabrics and is currently teaching classes on making leather shoes at the University of Texas. Visit her site to check out her pattern line: http://www.makethemyourself.com.