Scan for ITALIC to glean only what you need to know on the basics of industrial sewing thread. There have been many a masters’ theses written on thread construction and performance. Also, there is a lot of science and testing tools for abrasion testing, breaking points, colorfastness, and even more factors. All this information could fill a giant library. Unless you are pioneering a new material or developing for conditions on mars, then you’ll probably be fine with the basic knowledge contained in this article.


Thread made for use on industrial machines that meets high production demands daily. Of the list of threads to use for industrial applications you’ll find;

  • Spun polyester
  • Bonded Nylon
  • Monofilament
  • K-e-v-l-a-r (we cannot actually write this highly protected copyrighted word)

Other types of threads won’t hold up for a variety of reasons. We’re going to stick to the simple facts of industrial sewing machine thread here though to keep moving.


Spun Polyester

Spun poly threads are used for sewing garments and are also known as general purpose threads. They look, feel, and sew like cotton. However, spun poly will last twice as long as a Poly-Cotton.  Bonded nylon, on the other hand, is only beaten by polyester when your project’s seams will be exposed to sunlight over long periods. Some outdoor clothing would do fine with nylon, but prolonged outdoor use is where spun poly really shines. It stretches 26% over time. This is useful because it lets the seams stretch with the fabric, allowing for 'breaking in' effect – just like bonded nylon. All the tex sizes we sell have an inconspicuous stitch appearance.

Use a tex 27 for:

  • Undergarments
  • Children’s clothing
  • Neckties
  • Bras and lingerie

Use a tex 45 for:

  • Bedspreads
  • Comforters
  • Sportswear
  • Winter gear
  • Uniforms

Use a tex 60 or higher for:

  • Furniture
  • Mattresses
  • Shoes
  • Awnings
  • Upholstery


Bonded Nylon Thread 69

Nylon Thread has excellent abrasion resistance to mildew, aging, and abrasion.  It stretches 26% over time. This is useful because it lets the seams stretch with the fabric, allowing for 'breaking in' effect. It also has excellent resistance to mildew and aging. Size 69 is a middleweight thread used on home and commercial machines with a size 100/16 to 110 /18 needle. Its’ stitch is not very noticeable. Anything below 69 is lightweight and anything over 69 means the stitches are going to show. 69 Nylon is also available in black and white prewound bobbins. Bonded 69 Nylon is so popular because it is used to sew anything from shirts & pants to leather, and holds up like a champ. You can even stitch up a 20 lb sandbag with it. 

Use Bonded 69 Nylon Heavy Duty Thread for;

Monofilament Thread

Monofilament thread, also known as invisible nylon, is made from a single filament. Monofilament is the choice for sewing "invisible" stitches. As for Elongation, Monofilament thread has an average stretch of around 31% over time. This gives the “breaking it in” effect. It also has an excellent abrasion resistance.

Use monofilament for:

  • Invisible seams
  • Applique and Patches
  • Dress Shirts, Fine Tailoring and other Garments
  • Hair wraps
  • Quilting and other Soft Home
  • Luggage and Handbags
  • Automotive
  • Outdoor Products


K-e-v-l-a-r Thread

K-e-v-l-a-r thread is one of the strongest commercial threads available. It is 2X stronger than nylon or polyester. It only stretches 2%. It does not melt. It won’t turn to ash until temperatures reach 800F degrees.  And it is expensive. 

K-e-v-l-a-r thread applications include;

  • Heavy-duty clothing
  • Conveyor belts
  • Harnesses
  • Reinforcement of plastics
  • Fire retardant applications
Call us at 1-800-241-4953 for a quote if you need this specific thread type.



Tex and Denier are how the industry refers to thread size.


Denier is the weight, in grams, of 9,000 meters of thread.


Weight in grams of 1,000 m of thread equals Tex.


Tex and Denier

Tex and Denier are the specifications to consider when choosing the correct thread size for meeting application requirements. Thread size numbering is expressed in several numbering systems. Tex and Denier are in the Direct system (weight of a fixed length). Industrial thread sizes are usually expressed by Tex size or Ticket number. When only the total Denier is known, to determine a filament thread Tex size you must multiply the Denier by 0.1111 -

Denier x .1111 = Tex

Tex is an approximate number, which is very close to the Tex size of filament threads. Manufacturers reference ticket numbers for total Denier. 70 is the ticket number for 69 nylon with a 210 Denier. 3 plies of 210 is equal to 630 Denier. With 5% added for twist contraction, the total Denier is 662. This is classed a Tex 70 and Ticket number (Tkt.) 69.


What you really need to know is this:

  1. Higher Tex numbers mean thicker threads
  2. Lower Tex numbers mean finer threads


Elongation – Breaking Point

Elongation is how far a thread stretches before reaches its breaking point. Elongation at break is expressed as a percentage of its original length.  If a thread measuring 100 cm can be stretched to 120 cm, at which point it breaks, it is said to have 20 percent elongation at break.


Effect of Elongation While Sewing

Different sewing tensions elongates thread differently. The loop is affected by applying more tension. The stretch will become more and affect the loop formation. The loop formation will be larger if stretched less at certain sewing tensions. It will become difficult to catch and will improperly form the stitch if it stretches more.


Thread Elongation at Break in Seam Performance

Selection of a thread based on its elongation properties plays a major role in achieving seam stretch, which is the prime indicator of a quality finished product.

Seam performance depends on seam stretch. If the percentage elongation at break of a thread is less, the amount the seam can stretch before it breaks will also be less. This, in turn, affects seam performance. Hence, it is better to have a thread with optimal elongation properties to obtain good seam performance. Optimal elongation should not be too high, or too low. Elongation should be balanced or controlled as needed, and specific needs can be met by threads with different construction and manufacturing techniques.


Along with thread elongation, other factors that can support seam elasticity are a correct determination of stitch density, stitch type and seam type.

Generally, the higher the thread elongation, the better is the seam elongation, and in turn, the seam performance.



Thread Abrasion flex

Abrasion is one aspect of wear and is the rubbing away of the component fibers and yarns of the fabric. Flex abrasion-In this case, rubbing is accompanied by flexing and bending.


Factors affecting abrasion resistance:

Fiber type:

Nylon is generally considered to have the best abrasion resistance. Polyester and polypropylene also have good abrasion resistance. Blending either nylon or polyester with wool and cotton is found to increase their abrasion resistance. Viscose and acetates have the lowest abrasion resistance.

Fiber properties:

A fabric made up of longer fibers gives better abrasion resistance than short fibers because they are harder to remove from the yarn. For the same reason filament yarns are more abrasion resistant than staple yarns made from the same fiber. Increasing fiber diameter up to a limit improves abrasion resistance. 

Yarn twist:

An optimum amount of twist in a yarn gives the best abrasion resistance. At low-twist factors, fibers can easily be removed from the yarn so that it is gradually reduced in diameter. At high twist levels, the fibers are held more tightly but the yarn is stiffer so it is hard to abrade under pressure.

Fabric structure:

Fabrics with the crimp evenly distributed between warp and weft give the best wear because the damage is spread evenly between them. 



Colorfastness to light

A fabric’s degree of resistance to the fading effect of light.

Colorfastness to light is a measure of how permanent a color is on fabric after exposure to light. Both natural and synthetic fabrics are subject to discoloration under UV rays (sunlight) and fluorescent light.

In the test method ISO-105-B02 the tested sample is exposed to the influence of the light of a xenon lamp under certain conditions. Lightfastness grading is determined by comparing the level of color loss of the tested sample with blue standards. For example, grade 5 means that the characteristics of color fastness of the tested sample are similar to the characteristics of the blue standard 5.

·        Grade 5 – no fading

·        Grade 4 – slight fading

·        Grade 1 – high degree of fading


As stated at the beginning of this article, the amount of science behind all this stuff is mind-boggling. It took me a while to simplify the information to this basic format. CUTSEW sells the right thread for industrial sewing. We’ve been supplying the industry for over fifty years now. So you can either put your trust in the mystery thread being sold on Amazon or eBay or you can trust the old school industrial sewers that still haunt our warehouse (They are just back there listening to early Prince Albums and assembling machines).