Serger vs Sewing Machine: What Each One Does Best

Two machines, two jobs

A sewing machine forms a lockstitch: a spool thread on top meets a bobbin thread underneath.⁸ A serger has no bobbin. Several spool threads feed needles and loopers, and a knife trims the fabric as you sew.⁸ The result is the overlock stitch, which Kentucky says “resembles crochet or knitting stitches more than the stitch of a conventional sewing machine.”¹

A serger is also faster. Brother’s 1034DX manual gives 1,300 stitches per minute, against 300 to 800 for an ordinary sewing machine.⁴

Task by task

Which machine for which job

Job	Sewing machine	Serger
Seams in knits	Yes, with a stretch stitch or narrow zigzag7	Yes: “A stretch seam is needed, such as on a knit fabric” is one of Kentucky’s cases for the serger8
Seams pressed open	Yes1	No1
Finishing raw edges	Yes, with an overcasting stitch3	Yes, trimmed and wrapped in one pass2
Zippers	Yes1	The guides disagree1,2
Buttonholes	Yes1	No1
Topstitching	Yes1	No1
Backstitching	Yes8	No8
Narrow or rolled hems	Not covered by the guides we read	Yes4

Kentucky’s rule of thumb: use the serger for seams when the pattern fits, when the seam allowances don’t need to be pressed open, and when a stretch seam is needed.⁸ Their advice is to plan each project step by step and decide which machine sews which seam.⁸

Side by side: one sewing machine, one serger

To make the difference concrete, here are two Brother machines from our other guides, as Brother publishes them. The CS7000X’s 70 stitches include seven one-step buttonhole styles.⁹

Computerized sewing machine

Brother CS7000X (sewing machine)

Stitches

70, with 7 one-step buttonhole styles

Thread system

top thread and bobbin

Free arm

yes, with the flat bed attachment removed

In the box

hard case and wide table

Strengths

• Buttonholes and decorative stitches a serger cannot sew
• Free arm for sleeves and cuffs
• Hard case for carrying

Drawbacks

• No knife: edges are finished with a separate stitch
• Brother prints its weight without a unit

Good fit: you need one machine for seams, zippers, buttonholes and hems.
Skip it if: you sew heavy denim with thin needles: Brother warns the needle may bend or break.

2/3/4-thread serger, air threading

Brother AIR1800 (serger)

Threads

2, 3 or 4

Top speed

1,300 stitches/min

Knife

trims as you sew

Looper threading

air, with a pushbutton

Strengths

• Seams trimmed and overcast in one pass
• Air threading of the loopers
• 1,300 stitches per minute

Drawbacks

• No buttonholes, no topstitching
• Brother warns woolly nylon may not go through the air tube

Good fit: you already have a sewing machine and sew many knits.
Skip it if: it would be your only machine: it sews no buttonholes or zippers.

The CS7000X manual also warns that heavy fabrics such as denim with thin needles may bend or break the needle.¹⁰ The AIR1800 manual gives 1,300 stitches per minute and air threading for the loopers.¹¹

Which one to buy first

New Mexico State calls overlock machines specialized: “they do not replace the conventional sewing machine.”² Start with a sewing machine. Add a serger when you find yourself finishing many edges, or sewing knits every week. If your goal is professional-looking T-shirt hems rather than seams, compare a coverstitch machine as well.