Editing Overlock (section)

==Types==
Overlock stitches are classified in a number of ways. The most basic classification is by the number of threads used in the stitch. Industrial overlock machines are generally made in 1, 2, 3, 4, or 5 thread formations. Each of these formations has unique uses and benefits:

* 1-thread: End-to-end seaming or "butt-seaming" of piece goods for textile finishing.
* 2-thread: 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.
* 3-thread: Sewing pintucks, creating narrow rolled hems, finishing fabric edges, decorative edging, and seaming knit or woven fabrics.
* 4-thread: Decorative edging and finishing, seaming high-stress areas, mock safety stitches which create extra strength while retaining flexibility.
* 5-thread: In apparel manufacturing, safety stitches utilizing two needles create a very strong seam.

Two- and three-thread formations are also known as '''"merrowing"''' after the Merrow Machine Company.

Additional variables in the types of overlock stitches are the stitch eccentric, and the stitch width. The stitch eccentric indicates how many stitches per inch there are, which is adjustable and can vary widely within one machine. Different stitch eccentrics create more or less dense and solid-looking edges. The stitch width indicates how wide the stitch is from the edge of the fabric.  Lightweight fabrics often require a wider stitch to prevent pulling.

Adding extra variation in stitch types is the differential feed feature, which allows feed to be adjusted; extra-fast feed creates a ruffled or "lettuce-leaf" effect. Finally, some merrowing machines contain parts to roll the fabric edge into the stitch for added durability.

<gallery>
image:Overlock_1-thread.jpg|1-thread, {{cvt|5/8|in}} wide, 12 stitches per inch ({{cvt|1/12|in|mm|disp=out}} stitch pitch)
image:merrow 300204.jpeg|2-thread, {{cvt|1/8|in}} wide, 20 stitches per inch ({{cvt|1/20|in|mm|disp=out}} stitch pitch), with differential feed
image:Overlock_4-thread.jpg|3-thread, {{cvt|5/32|in}} wide, 17 stitches per inch ({{cvt|1/17|in|mm|disp=out}} stitch pitch)
image:Overlock_3-thread.jpg|3-thread, {{cvt|1/4|in}} wide, 7 stitches per inch ({{cvt|1/7|in|mm|disp=out}} stitch pitch)
</gallery>