How to Use a Serger: Threading, Tension, Differential Feed and First Seams

How to use a serger, step by step

1. Set up safely. Place the serger on a sturdy table with good light, such as a clamp-on Daylight Slimline 4, since the knife area sits in shadow. Raise the telescoping thread guide fully, and unplug the machine or switch it off before threading.
2. Put thread cones on the spool pins. Use serger cones such as the Maxi-Lock 4 Cone Pack. For practice, many sewists use four different colors so each thread path is easy to identify while learning to read the stitch.
3. Thread in the order your manual shows. Follow the color-coded diagram, usually printed inside the looper cover. Most manuals thread the loopers before the needles, and many specify upper looper, lower looper, then needles. Raise the presser foot so threads seat fully between the tension discs.
4. Set the standard settings. Turn each tension dial, the stitch length, the cutting width and the differential feed to the standard settings your manual lists for a 3 or 4 thread overlock. Many dials mark this range with color.
5. Make a thread chain. Hold the thread tails lightly behind the foot and turn the handwheel toward you a few times, then run the machine slowly until a chain of stitches forms off the back of the foot.
6. Sew a test seam. Take two layers of your actual project fabric, cut on the same grain, and serge about 6 in. Guide the fabric by the markings on the front cover rather than pushing or pulling it.
7. Read the stitch and adjust one dial at a time. Loops should meet at the fabric edge, lie flat and not pull the fabric. Change one tension dial by one number, sew again and compare. Use the tension table below to find the right dial.
8. Adjust differential feed. If a knit seam waves, raise differential feed above 1.0. If a light woven puckers, lower it below 1.0. Test after each change on fresh scraps.
9. Set stitch length and cutting width. Lengthen the stitch for thicker fabric and shorten it for fine fabric or a rolled hem. Widen the cutting width if loops pull in tightly or the edge curls, and narrow it if loops hang past the edge.
10. Sew the seam and finish the ends. Serge with the fabric edge along the knife, keeping pins clear of the knife line. Chain off at the end, then thread the tail through a blunt tapestry needle and bury it under the stitches, or trim it after a dab of seam sealant.

How do you thread a serger correctly?

Threading order matters more on a serger than on a sewing machine, because the loopers and needles form a chain that interlocks in a specific sequence. Thread out of order and the stitch will not form, or the threads will break. The most reliable method:

1. Clear the machine. If rethreading from scratch, unthread every path, starting with the needles.
2. Follow the colors. Each thread path has a color dot or line on the machine and diagram. Stay on one color from the cone to the eye before starting the next.
3. Lift the presser foot while threading. It opens the tension discs so thread can seat properly. A thread that sits on top of a disc rather than between the plates causes loose, loopy stitches.
4. Turn the handwheel toward you to bring the loopers into the best position, if the manual shows that step.
5. Check your work by gently pulling each thread near the eye; you should feel even resistance from the tension disc.

Owners of the Brother 1034D frequently say the lower looper is the only difficult path, and that it gets easy after a few practice runs. To change color without rethreading, use the tie-on method: cut the old thread near the cone, knot on the new thread, lower the tensions to zero, pull each thread through (needles one at a time, trimming the knot before it reaches the needle eye), then reset the tensions.

What should serger tension look like?

A balanced 4 thread overlock has straight needle lines on top, upper looper thread lying flat across the top of the seam allowance, and lower looper thread lying flat underneath, with the two looper threads meeting exactly at the fabric edge. When something is off, the fault shows up as a looper thread that is too tight, too loose, or wrapped to the wrong side. Change one dial at a time, and record the settings that work for each fabric on a sticky note.

If no amount of dial turning helps, rethread every path from scratch. A thread that slipped out of a guide causes far more serger trouble than a wrong setting. The 1034D review covers why that machine skips stitches, and the causes apply to most sergers.

How do you use differential feed on a serger?

Differential feed runs the front feed dogs faster or slower than the back ones. At 1.0 they move together. Above 1.0, the front dogs push extra fabric under the foot, which stops knits from stretching. Below 1.0, the front dogs hold fabric back so light wovens stay flat. Machines like the Janome 8002D and Janome MyLock 634D list a range of 0.5 to 2.25.

Test on scraps cut in the same direction as your pattern pieces, since knits stretch more across the grain than along it. If a knit seam still waves at the top of the range, lengthen the stitch slightly and avoid pulling the fabric as it feeds.

How do you adjust stitch length and width on a serger?

Stitch length is the distance between stitches, set by a dial or knob. Longer stitches suit thicker fabric and sweater knits; shorter stitches give a denser, neater edge on fine fabric and rolled hems. Stitch width is the distance from the needle line to the fabric edge. It is set two ways: by which needle you use (the left needle gives a wider seam than the right) and by the cutting width dial, which moves the knife. The Brother 1034D lists a stitch width of 3 to 7 mm, and the Janome MyLock 634D lists a cutting width of 3.1 to 7.3 mm.

Patterns for home sewing often use a 5/8 in seam allowance, while a serged seam sits much closer to the edge, so the knife trims the extra as you sew. Check your pattern's allowance with the seam allowance calculator and the seam allowance chart before cutting.

How do you serge curves, corners and the ends of a seam?

• Curves. Watch the knife, not the needle. Guide the fabric so the knife follows the cutting line, and turn gradually. Slow down on tight curves such as necklines and armholes.
• Outside corners. Serge off the edge at the first side, then turn and serge the next side, letting the stitches overlap slightly. For a sharper corner, trim the second side a short way ahead so the knife enters cleanly.
• Circles, like cuffs and hems. Start with a short angle into the edge, serge around, then overlap the first stitches by about 1 in, raise the needles, and serge off to the side.
• Ends. Leave a chain of 3 to 4 in, then bury it back under the stitches with a blunt tapestry needle, or trim it after seam sealant dries.
• Pins. Place pins well away from the knife line, or use Clover Wonder Clips 50, and remove them before they reach the foot. Hitting a pin can nick the knife and break the needle.

Unpicking a serged seam is slow, so baste tricky seams on your sewing machine first. When you do have to remove stitches, a sharp Clover Seam Ripper through the needle threads lets the looper threads pull free.

What do you need beside the serger itself?

Plan on a few small items: cones of neutral serger thread, a pack of the needle type your manual specifies (the Juki MO-654DE takes household HAx1 needles; some machines specify ELx705, such as Schmetz ELx705 Needles), a spare knife, tweezers, a lint brush, sharp Gingher Thread Snips and a bright task lamp. Many sewists set the serger to one side of the sewing machine on an L-shaped table so they can swivel between machines without standing up.

When you are comfortable with seams, the next step for knit garments is a coverstitch machine for ready-to-wear hems. Serger vs coverstitch explains the difference, and how to choose a serger covers upgrades such as 2-thread stitches and air threading.