How to Set Up a 4-Thread Overlock Stitch on a Baby Lock Serger
If you’re learning your serger (or you just want a reliable “home base” stitch), the 4-thread overlock is the one you’ll reach for constantly. In this video, we walk through setting up a basic 4-thread overlock stitch on a Baby Lock Triumph (and the same approach applies to many Baby Lock sergers).
The best part? On Baby Lock models with Automatic Thread Delivery (ATD), you don’t have to babysit tension dials—because there aren’t any.
What a 4-thread overlock stitch is (and why it matters)
A 4-thread overlock uses two needles + two loopers to create a strong seam while finishing the raw edge at the same time. It’s a great choice for:
-
garment construction (especially knits)
-
sturdy seams that still have a little give
-
clean, professional seams in one pass
The Baby Lock advantage: no tension dials + thread in any order
If you’ve ever heard “you must thread in this exact order or chaos will reign,” Baby Lock owners get to smile a little.
Many Baby Lock sergers (including Triumph-style machines) feature ATD, which means no manual tension adjustments, and you can generally thread in any order—super helpful if one thread breaks mid-project.
Step-by-step: setting up a 4-thread overlock on a Baby Lock
1) Install both needles
A true 4-thread overlock uses two needles. Make sure both are inserted correctly and fully seated.
2) Set your machine to a standard overlock stitch
On the Triumph and similar Baby Lock sergers, select your basic overlock setup. This gives you a solid starting point for stitch width/length and cutting settings (you can fine-tune after testing).
3) Thread the machine (no “special order” stress)
Follow your machine’s threading guides for:
-
upper looper
-
lower looper
-
right needle
-
left needle
With Baby Lock ATD machines, you can thread in any order, but you still want to follow the correct path for each thread so the stitch forms properly.
4) Confirm stitch length + cutting width
This stitch is very forgiving, but you’ll get a prettier result if you start with:
-
a “normal” stitch length for construction
-
a cutting width that lets the looper threads wrap the edge neatly (not falling off the edge and not tunneling inward)
5) Test on scrap and make small adjustments
Even with ATD, you’ll still adjust fabric-handling settings depending on what you’re sewing:
-
Differential feed (especially for knits—prevents waviness)
-
stitch length (longer for heavier fabrics, slightly shorter for lighter fabrics)
-
cutting width (if the stitch is hanging off the edge or wrapping too far)
Do one change at a time and test again—quick and easy.
What a “good” 4-thread overlock should look like
When it’s dialed in, you’ll see:
-
looper threads wrapping right on the fabric edge
-
two needle lines that look even and straight
-
no waviness (unless your fabric is stretching—then adjust differential feed)
Watch the video tutorial
If you want to see the exact setup on the Baby Lock Triumph—including what to look for as the stitch forms—watch the full tutorial here.
Come hang out in our Serger-Obsessed Corner of the Internet
If you want serger tips, troubleshooting help, settings chats, project inspo, and that “oh good, it’s not just me” feeling—join our private Facebook group all about sergers!
Ready to bring home a serger (or upgrade)?
At My Girlfriend’s Quilt Shoppe, we know a serger is the secret to professional-looking seams, flawless finishes, and stretch-friendly stitches. That’s why we carry trusted brands like Brother and Baby Lock, offering everything from beginner-friendly models to advanced sergers with cover stitch options. Whether you’re sewing garments, home décor, or quilting accents, we’ll help you choose the serger that takes your stitching to the next level.
You can shop sergers right on our website—beginner-friendly options all the way up to feature-packed dream machines.