How To Choose The Right Sewing Thread

How To Choose The Right Sewing Thread

Charlie Bradley Ross Wednesday, 9 April 2014

Inspired by the recent restocking of our beautiful organic cotton threads, we thought we'd explain a little more about threads in general, and why organic cotton is so great.

How Do You Choose A Sewing Thread?

Knowing which thread to choose for your sewing project is a key to a successful sew! Thread that is too small or weak will leave you with a creation that falls apart, while thread that's too wide or coarse may split or tear the fabric!

Start With The Fibre:

  • Cotton threads: Threads just like ours, found on reels in most haberdashery and craft stores are ideal for basic sewing and delicate fabrics, such as lingerie and sheer material. Most cotton threads are mercerised, a coating that lets the dye take more easily and results in a lustrous appearance. This cotton has limitations, however, as it has no "give" and can break if used on fluid fabrics, such as stretch knit fabric. Luckily, our organic cotton thread isn't mercerised.
    • All-purpose cotton (ours!) - a medium thickness cotton is suitable for sewing a wide range of projects using lightweight to medium cotton, linen and rayon fabrics.
    • Stranded cotton - this is made of six strands that have been woven together loosely. These are usually used in embroidery and are often best unwound prior to use or the end result will be too thick, although with wider weave fabrics, using all strands can sometimes be very effective.
    • Coton perlé - this thread cannot be divided and is used in embroidery projects to produce a neat sheen.
    • Coton à broder - an embroidery cotton in varying weights. It has a smooth quality.
    • Tatting thread - not a separate thread as such, but the type of cotton required for tatting is very specialized. It should be highly mercerized and tightly twisted, so that it is very firm and smooth.
    • Flower thread - this has a matte sheen and is soft. This thread is ideal for embroidery projects that require a rustic, old-fashioned look, particularly samplers on fine linen. It is only suitable for fabric with a small count.
    • Quilting thread - this is all-cotton thread that is coated for ease of movement through quilt fabric and batting. Obviously, this is ideal for quilting projects.
  • Polyester threads: These are strong threads that have excellent give for sewing projects. They tend to come in an all-purpose weight (size 50); they often have a wax or silicone finish that allows the thread to slip through fabric with little friction. This is suitable for most machine and hand sewing projects. This thread is suitable for fabrics with stretch in them and is especially good for woven synthetics, knits and stretch fabrics. The appearance of this thread will be waxy or shiny, not matte like plain cotton.
    • All-purpose thread - this is cotton-wrapped polyester thread and is widely available for sewing. This is suitable for using with most fabrics and is cheap and easily obtainable. It is not, however, a good thread to use for embroidery projects.
    • Invisible thread - this is similar to fishing line. It's strong and it's invisible, making it ideal for projects where you need the sewing to be strongly kept in place and hidden at the same time.
  • Heavy duty aka Top stitching: Heavy duty thread is ideal for heavy duty fabrics, such as those used in soft furnishings like upholstery and window dressings, vinyl, and coat fabrics. This is usually around size 40 and can be made from polyester, cotton-wrapped polyester, or cotton.
  • Rayon threads: Rayon embroidery thread works well to create flat stitches where cotton embroidery thread might stand too high.
  • Nylon threads: This is a strong thread that is suitable for using on light to medium weight synthetic fabrics. It is a fine thread, usually in size A.
  • Silk threads: Silk is a fine thread that is ideal for a range of fabrics, although silk is often reserved for embroidery work, same for silk ribbon. This strong thread is ideal for sewing on silk and wool, and for for basting all fabrics. The benefit is that silk threads do not leave holes and it is very flexible. An excellent tailoring thread.
    • Silk floss - this thread has a high sheen. It is also known as Japanese silk. It comes untwisted and can be used as it is, or divided to make even finer stitches. This thread is suitable for embroidery projects and for using on silk fabric projects. Although strong, it is delicate to work with, so it is vital to have trimmed fingernails to avoid catching and tearing.
    • Twisted silk - this thread consists of several strands of silk twisted together; again it is ideal for embroidery and can be used as it is, or separated into smaller threads.
    • Stranded silk - these threads have a sparkling look and can be separated into strands for sewing in embroidery projects.
    • Silk ribbon - silk ribbon is used for silk ribbon embroidery, both as projects in their own right, and for decorative projects such as on handbags, tops, skirts, etc. and for hair accessories.
  • Wool threads: Wool threads tend to be used for embroidery projects and for blankets (using blanket stitch). Wool works best with heavy fabrics, such as wool, or canvas.
    • Persian wool - Persian wool consists of three strands. You can use the three strands together or separate the threads to use singly. Whether or not you separate the threads will depend on the project and the thickness of the fabric being sewn.
    • Tapestry wool - this wool is not as thick as the Persian wool. It is not dividable.
    • Crewel wool - this is the finest of the wool threads. It is ideal for crewel embroidery projects. While it is fine, you can weave it into a thicker thread by twisting with more threads.
  • Machine threads: These are the threads inserted into a sewing machine.
    • Bobbin threads - this is an affordable thread that goes on the bobbin; it is commonplace for use on sewing machines and is used for a wide variety of general sewing projects made on the sewing machine.
    • Variegated thread - these threads are dyed different shades, the variegation repeating along the length of the thread in an even manner. Suitable generally for embroidery projects or colorful sewing projects, such as crazy quilt jackets, etc.
  • Metallic threads: Metallic threads are used for goldwork embroidery and for embellishment on items such as handbags. The colors are gold, silver, and copper.
    • Purl thread - this thread is hollow. Also twist thread and pearl purl
    • Japan thread - this is a very fine metallic thread that usually requires two threads used at the same time.

What Thread Size Should I Use?

What do those numbers like 30/2 and T-25 mean? Those numbers refer to the size of the thread, and are all based on weight, not diameter. Contrary to popular belief, the sewing industry usually doesn't measure thread diameters (monofilaments being an exception). There are a lot of thread sizing systems, so we'll go through the most widely used: The cotton count system, the tex system, and the metric ticket system.

Starting a couple of hundred years ago, every community of spinning mills had their own thread sizing system. And each mill had a different measure for each fibre as well (that's a lot of systems!). One thing that remained constant - All thread sizing systems were (and still are) based on length and weight. There are a few reasons for this. Firstly, from the spinning mill's point of view, a pound of fibre is a pound of fibre. The more thinly it's spun, the more thread you can make. Once mechanised ring spinning was introduced around 1830, the additional labor or wastage needed to spin more finely became negligible. Secondly - how, exactly, would you even measure a thread's diameter!? Making tiny measurements was much harder 200 years ago than it is today, and it's still no easier today! It literally has a fuzzy boundary, so if you looked at one under a microscope, where would the thread end? Three different judges would all reveal different answers. Measuring the length and weight of a thread, however, is much more accurate (and easy!)

Thread weight is measured when the thread is "griege" or undyed. As you can imagine, dyes, sizing, lubricants and bonding agents can all increase the weight of the yarn, sometimes very significantly. Similarly, thread length is measured when the thread is not under tension, as all threads have some amount of stretch. Loosely spun yarns can have an enormous amount of stretch!

Because thread sizing is based on weight, threads made from different materials can be different in size but have the same number (or have the same size but different numbers). That is true no matter which specific thread sizing system you use. For a given weight, there will be less fiber from dense materials than from lighter ones. This is actually noticeable when comparing extruded filament synthetics (nylon or rayon) against spun staple cotton.

What is The Cotton Count System?

The cotton count system is based on the number of 840 yard hanks you get from one pound of thread. You get 8,400 yards of size 10 (coarse) or 84,000 yards of size 100 (extremely fine) from one pound of cotton yard in this system. The size is measured for an individual yarn or strand. Most threads are made from multiple strands or plys. In the cotton count system, 50/2 means a two-ply thread made from two size 50 yarns. That has the same fibre content as one size 25 yarn.

The cotton count system is sometimes called the yarn size system. Despite the use of arbitrary and archaic units, the cotton count system is still used heavily world-wide to describe fabric yarns as well as sewing thread.

Did you know: "Super 120s" and similar wool yarn sizing is the product of marketing deparments, not an actual sizing system. However, cotton count sizes are used for most other fabric yarns.

While this system grew out of the cotton spinning industry, its use is not restricted to cotton threads. Polyester and polyester-cotton threads are frequently sized in this system.

What Is The Tex System?

The Tex system is based on the weight in grams of a thread 1 kilometer long. A kilometer of tex 10 (very fine) thread weighs 10 grams, while a kilometer of tex 100 (very coarse) weighs 100 grams. The Tex system measures the entire thread, no matter how many strands or plies it has. While a thread can have any actual weight, the Tex system has official ranges of sizes that get the same Tex number. For example, all threads weighing between 24.0 and 26.9 grams per kilometer are designated T-24.

The ISO (International Organization for Standardization) is pushing Tex for national standard use world-wide. Suppliers and contractors who don't normally work in Tex should still be familiar with it. And there are some parts of the industry (embroidery floss, knitting yarns) that have not started using Tex measurements.

What is The Metric Count System?

This system is based on the number of 1 kilometre hanks you get from one kilogram of thread. To put it into an equation, the metric count size is 1000 divided by the Tex size. So size 100 is a fine thread and size 10 is extremely coarse. This system is sometimes called thread weight, but should not be confused with the other thread weight system based on cotton count (explained above). Usually, the metric count system is applied to an entire thread, but sometimes the individual ply size and ply count are given.

Watch Out: Don't assume 70/2 is a cotton count size. It could be a metric count size. Metric ticket gives the metric count yarn size for the 3-ply thread with the same weight as the thread being measured. In other words, metric ticket is three times the metric count for the whole thread.

Why Use Organic Cotton Thread?

Organic cotton is a cotton fibre that has been grown according to the principles and rules of organic agriculture. These rules are very strict and are defined by a law from the European Union. Organic agriculture uses no synthetic pesticides or fertilisers, and no Genetically Modified Organisms (GMO). Organic fertilisers (such as compost) and plant-based pest management products (such as neem or garlic extract) are used. However, organic agriculture is not merely about replacing synthetic inputs with natural ones. The major principle is to restore a natural balance within the farm, with healthy soils, rich in organic matter. In such an environment, the pests are not systematically destroyed by poisons but are kept under control by their predators, just as they are in nature.

Our Organic Cotton Threads

Our threads are made from long staple fibres, these ring spun and combed threads are strong and soft. It's very fine, so it's suitable for hand sewing and machine sewing. The cotton used is 100% certified organic cotton to the Global Organic Textile Standard (GOTS) and the Soil Association standards.

There are 100m on each spool and even the spools themselves are ethical, as they're made from reclaimed / reused vintage wood.

The threads are also parallel precision wound (very technical term!), which basically means you can sew like a dream and not worry about funny tensions.

AND we have them available in 34 colours (not all in stock all the time though; wholesale is available).