Cotton Overlock Thread: A Buyer’s Guide

05 September 2025

Choosing the right thread is a big decision for garment manufacturers and home textile producers. The thread is not just a functional part; it affects the final product’s durability, appearance and quality. Among the many options available, cotton overlock thread is the best choice for many applications. We invite you to explore the different aspects of cotton overlock thread, including its types, uses, and tips for achieving optimal results.

This guide covers cotton overlock thread benefits, types and practical tips for selection and use. This will help textile wholesalers and manufacturers make informed buying decisions to improve their production process and deliver better products.

Introduction to Cotton Thread

Cotton thread is a staple in the world of sewing projects, prized for its natural fibers and soft, comfortable finish. Made from high-quality cotton, this thread is known for its breathability and durability, making it an excellent choice for a wide variety of fabric types, including cotton, linen, and even delicate silks. Whether you’re working on garments, home décor, or other creative projects, cotton thread delivers a natural look and feel that enhances both the appearance and comfort of your finished pieces. When selecting cotton thread, it’s important to consider the specific fabric type and project requirements to ensure the best results. Its versatility and reliability make it suitable for everything from everyday clothing to special crafts, providing strong, comfortable seams that stand up to regular wear.

Serger Machines and Thread

Serger machines are engineered to deliver professional-quality finishes, and the type of serger thread you choose plays a crucial role in the final outcome of your sewing projects. Serger thread is typically thinner and smoother than standard sewing thread, allowing for efficient, even stitching that’s essential for clean, durable seams. When working with serger machines, it’s important to match the thread to your fabric type and project requirements. Cotton thread is ideal for natural fibers, offering a soft, comfortable finish, while polyester thread is better suited for synthetic fabrics due to its strength and flexibility. Nylon thread can also be used for projects that require extra stretch or resilience. By selecting the right thread for your serger and fabric, you ensure that your stitches are smooth, strong, and perfectly suited to your project’s needs.

Benefits of Cotton Overlock Thread

Cotton overlock thread, also known as cotton serger thread, has several advantages that make it the preferred material in professional textile manufacturing.

Heat Resistance: Cotton’s natural fibers can withstand high ironing temperatures without melting. This is perfect for garments and textiles that need frequent pressing, so you get a clean professional finish without damaging the thread.
Dyeability: Cotton thread absorbs dye really well. This is important for post-production garment dyeing as it allows the thread to match the fabric’s color perfectly, creating a seamless and uniform look.
Softness and Comfort: Being a natural fiber, cotton is soft to the touch. When used for serging seams, it produces a finish that’s comfortable against the skin, reducing irritation. This is especially important for garments like lingerie, baby clothes and loungewear.
Strength and Durability: Despite being soft, high quality cotton thread is strong and provides durable seams. It can withstand the stress of daily wear and tear, extending the life of the final product.
Eco-Friendly: As a biodegradable, renewable resource, cotton is an environmentally friendly choice. For businesses focused on sustainability, using cotton thread fits into green manufacturing practices.

Cotton overlock thread provides a complete solution for manufacturers seeking durability, colorfastness, and a professional finish. These benefits ensure customer satisfaction and consistent results for a variety of sewing projects.

Types of Cotton Overlock Thread

Understanding the different types of cotton thread available is important for selecting the right one for your needs. Exploring different thread types, such as spun and core-spun options, is essential for achieving the best results. The main differences lie in the treatment and construction of the thread, and selecting the right thread type is crucial for specific projects with unique requirements.

Mercerized Cotton

Mercerized cotton is a premium cotton thread that has undergone a special chemical treatment to enhance its strength, durability, and sheen. During the mercerization process, cotton fibers are treated with sodium hydroxide, which causes them to swell and align more closely. This results in a thread that is not only more resistant to shrinkage but also boasts a smoother, more lustrous finish compared to regular cotton thread. Mercerized cotton thread is an excellent choice for projects that demand exceptional quality and durability, such as garments, embroidery, and decorative home décor. Its enhanced properties ensure that your finished pieces maintain their beauty and integrity through repeated use and washing.

Glazed Cotton

Glazed cotton thread is coated with wax or other starches and then polished to a high sheen. This process increases the thread’s strength and abrasion resistance, making it suitable for heavy duty fabrics like canvas and denim. The smooth hard finish allows it to pass through thick material with minimal friction.

Corespun Cotton

Corespun thread combines the benefits of different fibers. It has a high tenacity polyester filament core wrapped in a cotton staple fiber. The result is a thread with the strength and elasticity of polyester and the heat resistance and sewability of cotton. Corespun cotton serger thread is a versatile high performance thread for demanding applications that requires both durability and a natural finish.

How to Choose the Right Cotton Overlock Thread

Choosing the right thread involves considering several factors related to your project and production process.

Fabric Compatibility: The thread’s weight should match the fabric’s weight. A lightweight thread is good for delicate fabrics like silk or chiffon, while a heavier thread is needed for denim, canvas or upholstery. Using an incompatible thread can cause puckering or weak seams. Consider the type of fabric, such as knits and lightweight fabrics, as these may require specific threads and serging techniques for optimal results.
Project Application: Determine the end-use of the product. For garments that will be frequently ironed or garment-dyed, 100% cotton or mercerized cotton is the best choice. For items that require high strength like workwear or outdoor gear, corespun cotton thread is the best. For quilting projects, specialty threads such as metallic threads can be used to add decorative effects and enhance visual appeal.
Machine Compatibility: Ensure the thread is compatible with your overlock or serger machines. Refer to your machine’s manual for recommended thread types and sizes. Using the wrong thread can cause tension issues and inconsistent stitch quality. Proper threading of your machine is essential for achieving optimal stitch quality and professional results.
Color Matching: For most projects, the goal is to have the thread blend seamlessly with the fabric. Choose a color that is a shade darker than your fabric, as it will appear lighter once stitched. For garment dyeing, a dyeable cotton thread is essential.

Serger threads are often sold by the cone or in value sets, allowing you to choose the quantity that best fits your project size. Large cones are ideal for continuous sewing and are especially useful for both small and large projects, ensuring you have enough thread for uninterrupted stitching. Considering how the thread is sold and the quantity available can help with efficient project planning and cost management.

Tension Settings

Getting the tension settings right on your serger machines is essential for achieving high-quality stitches and professional results. Proper tension ensures that the thread feeds smoothly and evenly, creating balanced, secure seams that enhance the overall quality of your project. If the tension is set too tight, the thread may break or cause puckering; if it’s too loose, stitches can become sloppy or uneven. To find the ideal tension settings for your specific project and thread type, consult your machine’s manual and test different adjustments on scrap fabric. Taking the time to fine-tune your serger’s tension will help you achieve consistent, beautiful stitches every time.

Tips for Working with Cotton Overlock Thread

To get the best results when using cotton serger thread, follow these practical tips.

Use Good Needles: Always start a new project with a new needle. The needle type should be suitable for your fabric. A sharp good quality needle prevents skipped stitches and thread shredding.
Adjust Machine Tension: Cotton thread may require different tension than polyester thread. Test on a scrap piece of fabric to fine tune the tension for balanced stitches.
Clean Your Machine: Cotton fibers produce more lint than synthetic threads. Clean your overlock machine regularly especially around the loopers and feed dogs to prevent lint buildup that can affect performance.
Proper Storage: Store your thread in a dark environment, away from direct sunlight and dust, to preserve color and material quality. Light can fade the color and dust can clog your machine. Using thread nets can also help manage cones and prevent unwinding.
Hand Sewing Tip: When using cotton thread for hand sewing, especially if it is natural or vegetable-dyed, special preparation may be needed. Natural dyes and vegetable matter can affect the thread's texture and performance, so consider conditioning or treating the thread before use.

Thread Storage and Management

Maintaining the quality of your thread starts with proper storage and management. Large cones of thread should be stored upright in a cool, dry environment, away from direct sunlight and moisture, to prevent tangling and preserve their color and strength. Smaller spools can be organized in dedicated containers or thread organizers to keep them dust-free and easily accessible. Regularly inspect your threads for dust or debris, as these can affect the smoothness and quality of your sewing. By following these simple tips and keeping your threads clean and well-organized, you’ll ensure smooth, trouble-free sewing and achieve professional results on every project.

Common Issues and Solutions

Even with good materials, issues can arise. Here are solutions to common problems when using cotton overlock thread.

Issue: Thread Breakage
Solution: Check if the needle is old, bent or the wrong size. Make sure the machine is threaded correctly and adjust the tension as excessive tension can cause breakage.
Issue: Skipped Stitches
Solution: A worn or incorrect needle is a common cause. Replace the needle with one that is suitable for your fabric type. Also check if the needle is inserted correctly and fully.
Issue: Puckered Seams
Solution: This is often a tension issue. Loosen the needle thread tension slightly. Using a lighter weight thread or a smaller needle can also solve puckering on delicate fabrics.
Issue: Uneven Loops
Solution: This means tension imbalance between the upper and lower loopers. Adjust the looper tensions until the stitches are even and meet at the edge of the fabric.

Improve Your Products with Good Thread

Cotton overlock thread offers strength, softness and versatility. Its natural properties make it a reliable choice for various textile applications from high fashion garments to durable home goods. By understanding the different types and how to choose the right one for your needs, you can enhance the quality and value of your products.

For textile businesses looking to source good materials, choosing a reliable supplier is key. We offer a wide range of premium cotton serger threads and polyester sewing threads designed to meet the industry’s requirements.Get in touch