Types of Overlock Stitches Explained

Overlocking stitches, also known as serging stitches, are commonly used in garment construction and finishing, to sew seams, prevent fabric from fraying, and provide stretch and durability to seams. Overlockers can sew a variety of different overlock stitches for specific stitching tasks, this stitch glossary should give users a better understanding of their overlock stitches, when and where to use each stitch.

1. Triple Cover Stitch with Overlock Edge

• This stitch combines a triple cover stitch with an overlock edge, making it ideal for hemming and finishing seams on stretchy fabrics like knits. The triple cover stitch consists of three parallel rows of stitching on the top side, providing a strong and decorative finish, while the overlock edge secures the raw edges.
• Use it for hemming t-shirts, activewear, and swimwear; creating decorative seams on garments.

2. Double Cover Stitch with Overlock Edge

• Similar to the triple cover stitch, this stitch has two parallel rows of stitching on the top side and an overlock edge. It offers a good balance between durability and flexibility, making it suitable for hemming and finishing seams on medium-weight knits.
• Ideal for hemming casual wear, children’s clothing, and knit dresses; creating professional-looking finishes.

3. Safety Stitch Uses 5-Threads

• This stitch combines a 3-thread overlock stitch with a 2-thread chain stitch, providing a strong and durable seam. It’s ideal for heavy-duty fabrics and seams that need extra strength.
• Use it for constructing and finishing seams in denim, heavy canvas, and upholstery. Ideal for sewing high-stress areas like pants crotches and side seams.
• Further explanation of the difference between 5 thread and 4 thread stitches may be needed.

4. 4-Thread Overlock Stitch (4-thread)

• This is one of the most commonly used overlock stitches. It uses two needles and four threads to create a secure seam with an overlocked edge, providing a good balance of strength and flexibility.
• A perfect general garment construction stitch, for medium-weight fabrics, knitwear, and woven fabrics; finishing raw edges to prevent fraying.

5. Overlock Stitch (3-threads)

• This stitch uses one needle and three threads to create an overlocked edge, making it suitable for lightweight to medium-weight fabrics. It’s less bulky than the 4-thread version, providing a clean finish without adding much weight.
• Use it for finishing raw edges of seams, creating narrow rolled hems, sewing delicate fabrics like silk and chiffon, and making decorative edges.

6. Narrow Seam Satin Stitch (3-threads)

• As the image shows you can see how close together each stitch is, it is sewn with the stitch length close to zero as possible without causing the overlocker to jam. This gives us a stain stitch.
• Use it for fine to medium thickness fabrics, where a folded seam is not possible, or not required. This stitch still offers a neat edge and looks good, even when used on the outside or finished fabric edge.

7. Rolled Hem On Thick Fabrics (2-3 threads)

• Once the overlocker is set to sew a rolled hem, the stitch length can be adjusted to be a little longer, and is perfect to be used on thicker materials.
• The material is still rolled over, but because the material is thicker, the overlocker needs more thread to wrap that rolled edge.

8. Rolled Hem (2-3 thread)

• A typical neat looking rolled hem edge. The machine uses 2 or 3 threads and rolls the fabric edge, before wrapping it with an overlock stitch. The stitch length can be very close together or spaced a little, depending on your finished preference. It can be used in conjunction with the differential feed to form a classic wavy, lettuce leaf finished edge.
• Use this stitch for wrapping the edge of very lightweight, fine materials. Once sewn it forms a finished edge that can be seen, so I would suggest sewing a sample first to see how it looks.  

9. Tuck & Roll Edge (3-threads)

• A tuck and roll edge stitch on an overlocker is a specific type of decorative stitch that creates a rolled hem with a tucked appearance. This stitch combines the functionality of a rolled hem, which encases the raw edge of the fabric, with a slight tuck or pleat, adding a decorative element to the edge.
• The tuck and roll edge stitch is a versatile technique that enhances the aesthetic appeal of various fabric items while providing a clean and durable decorative finish.

10. Flat lock Stitch (2-threads)

• The flatlock is used when a cover stitch machine is not available. The fabric edges are butted together or slightly overlapped and sewn in a way that results in a flat, smooth seam with visible stitching on both sides.
• Must commonly used in sportswear, activewear, and underwear, where a flat and comfortable seam against the skin is essential.

11. Flat Lock Decorative Finish (2-threads. 1 is woolly nylon or bulk looper thread)

• The under side or rear of the fabric being sewn has a ladder type stitch, the top or front side can be seen in our image marked as No.11. Here we have used woolly nylon looper thread together with a regular polyester thread.
• Using a soft stretch thread like woolly nylon gives a nice decorative look to the flatlock stitch. Which, makes it look even more like a proper cover stitch, to provide a clean, professional look.