What is Sewing Thread?
Sewing threads are specially engineered multi-yarns designed to pass rapidly through sewing machines while enduring abrasion, stretch, and needle heat. Sewing threads are an example of a yarn that is specifically engineered for a specific purpose. Additional finishes are often added to yarns to ensure they are fit for purpose. Sewing threads are mainly produced in three-ply and occasionally two- or four-ply. Three S twisted single yarns are Z twisted to form a three-ply sewing thread. Sewing thread must be durable enough to withstand the abrasion, stretch and needle heat that occurs while sewing, garment finishing, stretching and recovery during wear.
Classification of Sewing Thread
Sewing threads can be classified based on substrate or material, for example polyester, cotton, lyocell, meta-aramid, para-aramid, nylon, polypropylene and PTFE; based on construction, for example air-entangled, braided, poly-cotton core spun, poly-poly core spun, monofilament, spun, spun-stretch broken, textured, twisted multifilament and monochord; and based on finish, for example bonding, non-wick, anti-fungal, fire retardant, water repellent and anti-static finishes.
Sewing thread could be classified in numerous ways. Some common classifications are those based on:
- Substrate
- Construction
- Finish
Classification Based on Substrate
- Natural: The utilization of sewing thread produced from natural fibers is very rare in industrial applications and cotton is the most frequently used natural sewing thread.
- Synthetic: The synthetic fibers have several advantageous characteristics compared to natural fibers such as high tenacity, better resistance to chemicals and higher abrasion resistance. Further, they are also not considerably influenced by rot, mildew, insects, bacteria and moisture.
Classification Based on Thread Construction
Spun Threads:
It is produced by utilizing natural as well as synthetic fibers. Spun polyester is the most frequently used sewing threads in garments. Spun threads have a hairy yarn surface, which provides better lubrication properties and softer hand. It gives exceptional sewing performance, however, it is lesser than the strength of continuous filaments.
1. Cotton threads
- Soft cotton threads
- Glazed cotton thread: The glazed process gives the thread a hard finish that shields the thread from abrasion and improves ply security
- Gassed thread: Gassing process otherwise known as singeing process is used to remove the protruding hairs and produce a lustrous thread. It is produced by moving the cotton sewing thread over a flame at a higher speed to reduce the hairy fibers on the surface of thread.
- Mercerised cotton thread: The cotton yarns are treated with caustic soda with 16%–18% concentration to improve the strength and lustre
2. Linen thread
3. Silk thread
4. Spun synthetic – fiber threads
5. Spun blended sewing threads
Core Spun Threads
Core spun thread is a mixture of staple fibers and filaments. The most commonly used core spun sewing thread has a multiple-ply structure, with each ply comprising a core polyester filament wrapped by the cotton or polyester staple fibers. The strength of thread is provided by the filament and sewability by means of cotton or polyester fiber wrap.
Continuous Filament Threads
It is produced by extruding the filaments from the synthetic polymer and is given a twist to improve the strength. The strength of these threads is stronger than spun threads for the same thread size.
a) Monofilament Threads: Monofilament sewing thread is produced from a single continuous fiber with a specific fineness. Although the monofilament sewing threads are stronger, more uniform and cheaper, they lack flexibility and are rough in feel. Because of this limitation, it is limited to sewing of hems, draperies and upholstered furniture.
b) Multifilament Threads: Multifilament sewing thread is generally produced from nylon or polyester and is utilized where high strength is a principal requirement. It comprises two or more continuous filaments twisted together to give more strength. It is frequently used to sew leather garments, shoes and industrial products. Three kinds of multifilament sewing threads are lubricated, bonded and braided threads.
c) Textured Threads: The texturisation enhances texture to the continuous filament yarns by providing softness and bulk. They are then slightly twisted and heat set to make it permanent. The texturised sewing threads give exceptional seam coverage. Although these threads provide more cover and high extensibility, they are more subject to snagging.
The types of textured sewing threads are (i) false twist textured filament threads, (ii) air textured filament threads and (iii) air-jet intermingled filament threads
Embroidery Threads
- Mainly required for decorative purposes
- Color and luster are two main requirements for embroidery threads
- Mostly made from mercerized cotton, silk, viscose rayon and polyester fiber/filament yarns
Technical Threads
- Specifically developed for technical/industrial uses
- Perform satisfactorily in adverse climatic, industrial conditions and heavy duty applications
- Generally made from aramids, glass, ceramics, etc.
Classification Based on Thread Finish
Normally special finishes are provided to the sewing thread for two purposes:
- To enhance the sewability of the thread – Certain finishes improve the thread strength, lubrication property and abrasion resistance.
- To accomplish a specific functional requirement – Several types of finishes impart the special finishes such as fire retardant, water repellent, anti-fungal and anti-static finishes.
Sewing Thread Size
Sewing thread size is the most significant factor in accomplishing the functional and aesthetic requirements of the finished garment. Sewing thread sizes could be expressed in direct or indirect numbering systems. Normally, metric count (Nm) is used to express synthetic, spun and core spun thread size while English count (Ne) is used to express the size of cotton thread. Filament sewing threads are generally expressed in denier or decitex.
In direct systems: Resultant thread size = Single yarn count/Number of plies
In indirect systems: Resultant thread size = Single yarn count × Number of plies
Sewing Thread Consumption
It is essential to know the consumption of sewing thread in a garment to
- Estimate the number of cones needed.
- Calculate the cost of sewing thread required to produce the finished product.
Thread consumption can be determined in numerous ways such as
- Determining the actual amount of thread consumption in a particular length of seam.
- Calculating the thread consumption by using stitch formulas.
- Calculating the thread consumption via thread consumption estimates.
Measurement of Actual Sewing Thread Consumption
For the determination of sewing thread consumption, the threads from the garment should be removed from a particular length of each different seam. Then, thread consumption could be determined by dividing the actual length of sewing thread after unravelling from the garment by the seam length.
Example:
Seam length = 220 cm
Stitch class 401 = Two-thread chain stitch
Seam length for which sewing thread is removed = 25 cm
Length of needle thread removed = 25.5 cm
Needle thread factor = 25.5/25 = 1.02
Length of bottom thread (looper thread) removed = 75.0 cm
Looper thread factor = 75.0/25 = 3.00
Total length of needle thread = 220 × 1.02 = 224.4 cm
Total length of bottom thread = 220 × 3.00 = 660 cm
Total sewing thread consumption = 224.4 + 660 = 884.4 cm
15% thread wastage can be added = 854 × 1.15 = 1017 cm
Determination of Thread Consumption Using Thread Consumption Ratios:
A simple technique of calculation of thread consumption is to utilize the standard thread consumption ratios for a range of stitch classes as given in Table 1. By connecting these thread consumption ratios to the seam length using each stitch type, the total thread consumption could be determined.
Table 1: Thread Consumption Ratio for Various Stitch Types
| Type of Stitch | Thread Ratio | No. of Needles | Needle Thread % | Looper Thread % |
| 101 — Chainstitch | 4.0 | 1 | 100 | 0 |
| 301 — Lockstitch | 2.5 | 1 | 50 | 50 |
| 304 — Zigzag Lockstitch | 7.0 | 1 | 50 | 50 |
| 401 — Two Thread Chain Stitch | 5.5 | 1 | 25 | 75 |
| 406 — Three Thread Covering Stitch | 18.0 | 2 | 30 | 70 |
| 503 — Two Thread Overedge Stitch | 12.0 | 1 | 55 | 45 |
| 504 — Three Thread Overedge Stitch | 14.0 | 1 | 20 | 80 |
| 602 — Four Thread Covering Stitch | 25.0 | 2 | 20 | 80 |
| 605 — Five Thread Covering Stitch | 28.0 | 3 | 30 | 70 |
Note: The thread ratios are attained by considering a stitch density of 7 stitches/cm.
Example:
Length of seam = 220 cm
Stitch class 301 = Single thread lock stitch
Thread ratio obtained from the table (thread length per cm of seam) = 2.5 cm
Total sewing thread consumption = 220 × 2.5 = 550 cm
Consumption of needle thread = 1210 × 0.25 = 275 cm
Consumption of looper thread = 1210 × 0.75 = 275 cm
By adding 15% wastage = 550 × 1.15 = 632.5 cm of thread per seam
Applications of Sewing Threads
The applications of different types of sewing threads in various types of fabrics are given in Table 2.
Table 2: Application of Types of Sewing Threads
| Fabric | Thread |
| Delicate fabrics Tulle, chiffon, organza | Fine mercerised cotton and synthetic thread, silk thread |
| Lightweight fabrics Satin, suiting, knits, deep pile fabric | Mercerised cotton thread, synthetic thread, silk thread |
| Medium weight fabrics Gabardine, denim coating, furnished fabric | Heavy duty mercerised cotton, cotton thread, synthetic thread |
| Heavy weight fabrics Dungaree, canvas fabric, upholstery | Mercerised cotton thread, synthetic thread |
| Synthetic knit and stretch fabrics Polyester double knit, jersey, velvet, nylon tricot | Nylon, mercerised cotton, cotton, silk |
| Leather materials Suede, kidskin, capeskin, lambskin | Mercerised cotton, silk and synthetic thread |
Sewing Thread Packages
Sewing threads are packaged and handled in different forms like cones, vicones and cops as shown in Figure 2. Small length spools are engaged in retail store distribution, whereas larger spools are utilized to a limited extent industrially.
Spools: It has relatively short length of thread and is wound as a parallel winding. It has a flange on both ends that obstructs with off winding on industrial sewing machines. Hence, these are made for home sewing use.
Cops: Cops are utilized mainly in lockstitch machines where a range of colors are used. Sewing thread is cross-wound on the cop package to increase in off winding. The length of thread in a small cop ranges between 100 and 2000 m and 400 and 4000 m on a larger size cop.
Cones: Cones are tapered shapes made of paper or plastic material. They may contain fairly longer lengths of sewing thread about 1000–25,000 m with length of traverse ranging from 10 to 15 cm. It gives good off-winding performance for high-speed sewing machines. It is the most economical form of thread package where the consumption is high.
Vicones: It is a parallel tube having a flange at the bottom, which is designed to contain thread lengths of 1000–5000 m with length of traverse 6.5–9 cm.
Containers: Containers are intended to handle smooth and lively monofilament sewing threads that are complicated to control with the traditional thread packages.
Cocoons: Cocoons are centre-less sewing thread package forms created for insertion in multi-needle quilting machines and some kinds of embroidery machines.
Pre-wound bobbins: These are precision-wound packages intended to substitute metal bobbins in lockstitch machines. Normally, more sewing thread is available and the length is more consistent in these packages. It eliminates rewinding of bobbins, and hence improves the productivity and off winding is also improved because of precision winding.
Conclusion
Sewing thread selection is critical for achieving the desired performance, durability, and appearance in stitched products. By understanding the different classifications, applications, and packaging options, manufacturers and consumers can make informed decisions to enhance seam quality and efficiency in production.
References
[1] Karthik, T., Ganesan, P., & Gopalakrishnan, D. (2016). Apparel Manufacturing Technology. In CRC Press eBooks. https://doi.org/10.1201/9781315367507
[2] Sinclair, R. (2015). Textiles and fashion : materials, design and technology. In Woodhead Publishing
[3] Garment Manufacturing Technology. (2015). In Elsevier eBooks. https://doi.org/10.1016/c2013-0-16494-x
[4] Textile and Clothing Design Technology. (2017). In CRC Press eBooks. https://doi.org/10.1201/9781315156163
