Getting to Know Sewing Thread Types

The massive variety of sewing thread types and sewing thread uses can feel overwhelming to a garment sewist.

How are you supposed to know which thread fibers and thread weights will work for your project?

It’s almost enough to make you take off running from the thread aisle at Joann.

There’s JUST. SO. MANY. OPTIONS.

Relax, I got you. In this article we will explore the wild world of thread for sewing machines:

• Thread fibers

• How thread is made (aka, what’s the difference between spun and corespun?)

• Thread types for sewing clothes

• How to read a spool

• Thread weight

• My fave thread brands

Because, if you understand sewing thread types, you will make better decisions when sewing your garments.

Better decisions = better sewing experience = better garments.

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What is Thread Made of?

Thread can be made of many different fiber, including (but not limited to):

• Cotton: Beloved by quilters. Natural fiber.

• Cotton/polyester: Strong but has the matte look of cotton. Cotton is a natural fiber; poly is synthetic.

• Linen: Usually too thick for garment sewing. Used to sew accessories. Natural fiber.

• Nylon: Strong. Synthetic fiber.

• Polyester: Stronger, stretchier, and smoother than cotton. Most common sewing thread fiber. Synthetic fiber.

• Rayon: Shiny and soft with vivid colors. Starts as natural fiber but is heavily processed. RELATED: Is Rayon Better Than Cotton? Fabric Guide for Sewists

• Rubber: For stretch fabrics. Natural fiber.

• Silk: Strong but will degrade over time. Used for hand sewing, beading, buttons. Natural fiber (and only the natural fiber that’s a filament fiber (see “How Thread is Made?”)).

• Wool: Thick and rough in texture. Natural fiber.

And there’s even thread made from Kevlar (bulletproof vest material) and Nomex, which is used for fire-retardant clothing.

RELATED: All About Getting a New Serger: Beginner Serger Supplies and More

How is Thread Made?

When you understand how thread is made, you can buy the good stuff immediately. And if you’ve ever discovered you bought crappy thread while you were sewing with it, well, you know exactly why you want the good stuff FIRST.

(FYI: Crappy thread breaks easily, frays, and creates a lot of lint.)

Here are the different ways thread can be made/processed:

Bonded: Coated with resin to reduce friction and increase strength. May not be usable in a domestic sewing machine.

Corespun: Spun (see below) cotton or poly is wrapped around a polyester filament (fiber of a continuous length). Strong with low-to-moderate lint creation.

Filament: Long, thin strands of fiber (vs. shorter staple fibers). Made of synthetic fibers, except for silk filament. Low lint, but not as strong as corespun.

Gassed: Also called silk finish or polished cotton. Cotton thread is passed through a flame to burn off lint.

Glazed or coated: Cotton coated with wax, resin, or starch and polished to increase shine and strength. Not recommended for machine sewing.

Mercerized: Cotton that’s been dunked in a caustic solution to improve its dyeability, strength, and luster.

Monofilament: A single strand of fiber — think fishing line.

Spun: Staple fibers (fibers of a discrete length) of cotton or poly are spun into single yarn plies and twisted together. Low cost, but more lint and not as strong as filament or corespun threads.

Textured: Poly or nylon is fluffed up by a mechanical process to make it more elastic.

RELATED: Sewing Machine Cleaning: 5 Maintenance Questions Answered

Sewing Thread Types for Garment Sewists

You’ve been to Joann. You’ve shopped online. You know there are A LOT of threads out there.

Here’s an alphabetical look at most/many of the sewing thread types you may *possibly* find yourself using as a sewist of garments.

Most of these threads are for sewing seams, but a few are decorative. I encourage you to test different sewing thread uses — especially when it comes to combos of tension, stabilizer, needles, and fabric.

There’s a good chance that your sewing machine will act funny with new thread, so perform trials before going for it on your fashion fabric.

All-purpose polyester

It is what it is — a poly thread to use for almost all sewing purposes. I use AP poly almost exclusively when I’m sewing clothes, because I don’t really need anything else.

Basting

Smooth, slippery, and glides through fabric easily. Thin enough to break by hand.

Blind stitch

Smooth and lightweight for maximum powers of invisibility.

Bobbin

Usually lighter in weight than all-purpose/needle thread. You often can buy pre-wound bobbins in neutral colors.

Button/hole

Heavier-weight thread that’s decorative and strong to attach buttons and beads and to create hard-working buttonholes.

Cotton

Cotton thread is not great for garments, because it rots over time and isn’t as strong as synthetic thread. Cotton also makes a lot of lint and degrades in UV light. Cotton-poly blends are a better option.

Denim/jeans thread

In general, you can use all-purpose polyester to sew jeans seams. Denim/jeans thread products often have a variegated blue color and are a cotton/poly mix that helps them blend into jeans color and texture.

Some denim/jeans thread products are intended for topstitching (e.g., gold thread). These threads are thick and probably too heavy for seams.

You can tell denim topstitching thread from denim seam thread with your fingers and eyes.

Elastic

This thread is for smocking, shirring, ruching, and ruffling fabric. Most importantly, it’s only for use as bobbin thread. Hand wind elastic thread on a bobbin; the machine will wind it too tightly and take out its stretchiness.

Extra fine

For very fine ornamental stitches and lightweight fabrics. Can be used with low upper thread tension and fine needles.

Fusible

Thread that acts like glue, with no stiffness. Good for applique. It adheres when melted with an iron, so it’s better for bobbin use. Usually nylon, poly, or a blend of the two.

Glow in the dark

Yes, there is such a thing as glow in the dark thread! The glow thread I found online was recommended for machine embroidery. It’s all poly and midweight, and you can use it in a domestic home sewing machine.

Invisible/transparent

Looks like clear fishing line. It’s monofilament thread, made of one long filament instead of multiple yarns twisted together. Invisible thread blends into fabric. It’s a synthetic material, either poly or nylon.

Some reviews of invisible thread online point out that it’s difficult to see and doesn’t like to stay threaded through the machine. Might be a good candidate for a thread stand and/or thread net.

Also: Nylon thread melts! Be careful.

Metallic

For decoration only — topstitching, monogramming, etc. Made of nylon and polyester. Used with a 110/18 needle, which is a big size. Speaking from experience, you need a big needle with a big eye to keep metallic thread from shedding and breaking, and you need to use stabilizer.

Rayon

Rayon thread is often used for machine embroidery, but you can use it in a home sewing machine. It has a beautiful luster and is slippery. Because it is slippery, I recommend placing a thread net over your spool.

Rayon thread isn’t as strong as poly thread, and rayon thread can bleed. Also, because this is a decorative thread, you probably will need some sort of stabilizer for best results.

Serger/overlocker

Serger thread is smooth, lightweight, strong, and can withstand the high speed and tension that comes with using a seger. It creates less lint than other threads to keep an overlocker cleaner. Usually polyester.

Topstitching

Topstitching thread is thicc, with two C’s. Most of my experience with topstitching thread has been topstitching jeans. It can be challenging to find the correct tension between topstitching thread in the needle and bobbin thread. Consider stabilizer with topstitching thread.

Wash away

Yes, this also is a thing. Good for basting and applique. Dunk in (warm) water and it dissolves. Make sure your fingers aren’t wet when using water-soluable thread.

Wooly texture

My favorite for sewing knits. The puffy, yarn-like texture is soft and flexible. Hand wind for a bobbin, or use it in the loopers of your serger. Usually made of nylon, but can be made of texturized poly, too.

RELATED: Favorite Sewing Supplies: An Epic List from an Advanced Sewist

How to Read a Spool of Thread

A spool or cone of thread is going to give you some useful information on types of sewing thread. Here’s what you might find and what it means.

• Fiber content: Polyester, nylon, etc. A spool with a “P” indicates polyester. For example, P60/3 is a polyester thread.

• Length: For most garments, I can get by with one 100-meter spool of Gütermann AP. I buy 500-meter spools in neutral colors.

• Color number/code/name: Important if you need to buy ANOTHER spool of a specific color of thread.

• Dye lot: Might be important if you’re desperate to match colors P-E-R-F-E-C-T-L-Y.

• Care instructions: Like what you’d find on a tag in a garment.

• Country of origin: Something like, “Processed in U.S.A. with China fiber.”

• How it was made: Spun, corespun, textured, etc.

• Thread weight:

Superior Threads has this amazing article about thread weight, if you want to go deeper. What follows is an abbreviated take on thread weight:

Weight

How many kilometers of thread it takes to make 1 kilogram. For example, 40 wt. indicates that it takes 40 kilometers to weigh 1 kilogram. Remember: Small wt. number = heavier thread.

Number System and Gunze Count

This system of weight measurement is a combo of Weight (wt.) and thread composition (Gunze). It’s can be abbreviated as No., Nm, or # (e.g., No. 100, Nm 100, #100).

Gunze count indicates the number of plies (strands) of yarn, and it appears behind a slash. For example, #50/3 means that the thread on the spool is made of three strands of yarn that each weigh 50 wt.

Now here’s the confusing part. A spool labeled No. 50 may not have the same thread weight as a spool labeled 50 wt. That’s because it could be a spool of Nm 50/3 thread, which means each of the three plies weighs 50 wt.

The Number System alone doesn’t tell you about how many strands of fiber were used to make the thread; it’s less useful on its own. Just remember: Small No./Nm/# = heavier thread.

Denier

Weight in grams of 9 kilometers of thread. For example, if 9 kilometers of thread weigh 600 grams, that’s 600-denier thread. Sometimes abbreviated Den or D. Remember: Larger denier number = heavier thread.

Tex

Weight in grams of 1 kilometer of thread. For example, if 1 kilometer of thread weighs 27 grams, it’s a tex 27. There’s also decitex (dtex for short). Dtex measures the weight in grams of 10,000 meters, e.g., 1 tex = 10 dtex. Remember: Larger tex number = heavier thread.

As you can see, there’s a grab bag of (confusing) ways to measure thread weight. To make sure you choose the right thread weight, I suggest:

1.) Paying attention to what a thread is called, e.g., all purpose, serger, etc. The thread *probably* will tell you how to best use it.

2.) Comparing like with like, e.g., tex to tex, wt. to wt., etc.

3.) Trusting your fingers. If you pick up a spool and the thread feels too thick, it’s probably too thick.

4.) Memorizing that 40 wt. = 225 denier = Tex 25. Gütermann’s most popular all-purpose thread — Mara 100 (polyester) — is Tex 30.

5.) Checking out this thread label code chart for examples.

6.) Remembering the following:

Small wt. number = heavier thread

Small No./Nm/# = heavier thread

Larger denier/Den/D number = heavier thread

Larger tex number = heavier thread

P.S. Wawak has this amazing chart matching thread weight to needle size. Love it and live it.

Tried-and-True Thread Brands

Based on personal use, the following thread brands are my favorites. (P.S. I’ve bought all these threads with my own 💸.)

Gütermann

If I’m buying thread at Joann (which probably is the sewing supply I buy most often at Joann), I’m buying Gütermann thread, period.

I’ve been burned by Coats & Clark, and I’m not going back.

Seriously, though — Gütermann all-purpose polyester Sew-all thread will get you through 98.7 percent of garment sewing.

What’s more, when I was at Mood Fabrics this spring, I noticed that Gütermann was the brand of choice. I guess Mood could have a good relationship with a Gütermann sales rep, but I like to think that the store wants to give its sewists the best stuff (at the best price point).

Mettler

I bought a multi-color pack of all-purpose poly Mettler Metrosene thread a while back after the “Sewing Out Loud” pod gals hyped it up hard.

And, I must say, the Metrosene delivered. It’s strong and smooth, and having a variety of colors on hand definitely has cut down on my trips to Joann. I almost *always* have thread that matches whatever I’m working on.

Madeira

I bought some big cones of Madeira Aerolock thread for my serger when it first came home. It’s 100 percent polyester and corespun.

I got the cones at the sewing machine store, because I figured they probably had the best stuff.

Yep, it’s the best stuff. It’s super smooth and strong, and the 2,000-yard thread cones last FOR-EV-ER.

Final Thoughts on Sewing Thread Types

I hope next time you buy sewing threads that you think about your decision in a different, more informed way. For example, if you have the option, you know that corespun thread is stronger and less linty than spun thread.

*Cue “The More You Know” jingle.*

Sewing thread uses may seem like a minor element of your sewing practice, but superior thread will help you reduce dust, have a better stitching experience, and allow you to create long-lasting, beautiful, one-of-a-kind garments.

It’s your turn: What’s your favorite thread brand? Have any notable thread horror stories to share? Please leave a comment. Thanks for reading.