An overlock is a kind of stitch that sews over the edge of one or two pieces of cloth for edging, hemming or seaming.
Usually, an overlock sewing machine will cut the edges of the cloth as they are fed through (such machines being called “sergers” in North America), though some are made without cutters. The inclusion of automated cutters allows overlock machines to create finished seams easily and quickly. Loopers serve to create thread loops that pass from
the needle thread to the edges of the fabric so that the edges of the fabric are contained within the seam.
Overlocking is also referred to as “overedging”, “merrowing”, or “serging”. Though “serging” technically refers to overlocking with cutters, in practice the four terms are used interchangeably.
Overlock stitching was invented by the Merrow Machine Company in 1881.
Formation of an overlock stitch
- When the needle enters the fabric, a loop is formed in the thread at the back of the needle.
- As the needle continues its downward motion into the fabric, the lower looper begins its movement from left to right. The tip of the lower looper passes behind the needle and through the loop of thread that has formed behind the needle.
- The lower looper continues along its path moving toward the right of the serger. As it moves, the lower thread is carried through the needle thread.
- While the lower looper is moving from left to right, the upper looper advances from right to left. The tip of the upper looper passes behind the lower looper and picks up the lower looper thread and needle thread.
- The lower looper now begins its move back into the far left position. As the upper looper continues to the left, it holds the lower looper thread and needle thread in place.
- The needle again begins its downward path passing behind the upper looper and securing the upper looper thread. This completes the overlock stitch formation and begins the stitch cycle all over again.
Brother Designio Series DZ1234
- An overlock machine is a special purpose machine used for finishing edges and sometimes seaming.
- Sew up to 1,300 stitches per minute to create couture-level fashions faster than ever.
- Easy Color-Coded threading so no struggle to thread serger.
- The Differential Fabric Feed offers a 0.7 – 2.0 ratio on many fabrics, even lightweight knits, offering durable and consistent stitch quality virtually every time.
- The stitch width can be easily adjusted between 3.0mm and 7.0mm.
Type of Stitches
1. TWO THREAD OVERLOCK
- Stitch type 503.
- One needle and one looper.
- Best for finishing seam edges and allowances.
- Has little effect on fabric drape and rarely causes a pressing imprint.
- Frequently used for serging edges on men’s slacks, lightweight fabrics or when using heavier decorative threads.
- Used when stitching active wear, elastic and lace.
- Also, hems can be sewn.
- Unsuitable for seaming, because does not hold plies securely, causing seam grim when stressed.
- Can be adjusted to sew a rolled edge.
- Edging and seaming, especially on knits and wovens, finishing seam edges, stitching flatlock seams, stitching elastic and lace to lingerie, and hemming. This is the most common type of overlock stitch.
2. THREE THREAD OVERLOCK
- Stitch type 504.
- Also called basic serging stitch.
- One needle to loopers.
- Stitch looks the same on both sides, hence good for reversible.
- It has excellent stretch and recovery.
- Has narrow bight 3-5mm used for finishing edges as a narrow, decorative rolled edge on napkins and scarves?
- Also for seaming budget garments.
- Most useful for sewing knits, wovens.
- Can be used as a stable seam finish on loosely constructed, ravel prone fabrics.
- Sewing pin tucks, creating narrow rolled hems, finishing fabric edges, decorative edging, and seaming knit or woven fabrics.
3. THREE THREAD OVERLOCK WITH A MICROPROCESSOR
- Based on regular overlock machine, this version is used for the assembly seaming of garments made up in light weight knitted materials.
- The microprocessor enables the accurate calibration of the stitch tension without manually adjusting spring tensioners and permits automatic cutting of the thread chain at the beginning and end of the seams.
- A tractor foot can be fitted to this machine when sewing seams with varying thickness.
4. FOUR THREAD OVERLOCK
- 2 needles and 2 loopers.
- All 4 threads are necessary to sew a serged seam.
- Can be converted to both 2 and 3 overlock.
- Suitable for sewing woven and knits.
- Can be used in areas that receive stress.
- Suitable for sewing blouses, shirts, skirts, pants, dresses, lingerie, action wear, swim wear and even sleepwear.
- Decorative edging and finishing, seaming high-stress areas, mock safety stitches which create extra strength while retaining flexibility.