What Type of Thread is Best for Sewing on Leather?
I am constantly asked what type of thread works best when sewing leather. Each time someone asks me I am surprised 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 I was looking for and I ended up pulling out some Rayon thread and using it on leahter. 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 Duel Duty (poly/cotton) blend; it is strong and sews nicely. The thread I found easiest to sew with was Rayon.
| Type | Rank | Pros | Cons | Breakage |
| Rayon | 1 | Even stitches. No fraying, breaking, or skipping of stitches. | Hard to Break | |
| Duel Duty (37% cotton/63% polyester) | 2 | Nice even seams. No pulling, tugging, or fraying of thread. | Hard to Break | |
| Quilting (32% cotton/68% polyester) | 3 | No pulling, tugging, or fraying of thread. | Slightly more sensitive to enlarging or reducing stitch length | Medium |
| Cotton (100%) | 4 | Nice even spaced seams. No pulling, tugging, or fraying of thread. | Did have a slight frayed look to end of thread going through needle. | Medium |
| Polyester (100%) | 5 | Didn’t fray or break during use. | Enlarged or reduced stitch length on its own. | Medium |
| Silk (100%) | 6 | Didn’t fray or break during use. | Enlarged or reduced stitch length on its own. | Hard to Break |
| Wool (100%) | 7 | Nice even spaced seams | It 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. | Easily |
| Sulky Metallic | 8 | Even spaced seams (when it would make them). | Broke every 3 inches. Frayed thread badly. | Easily |
| Sulky Metallic | 9 | Knotted, frayed, and broke constantly. Could not even get 2 inches of seam. | Easily |
