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A serger is the most thread-hungry machine in your sewing room. One seam can eat four threads at once, and a 4-thread overlock at full speed is exactly where cheap, linty thread falls apart. Skipped stitches, bird-nesting in the loopers, and constant rethreading are almost always a thread problem, not a machine problem.
Serger thread is not the same as the all-purpose thread on your sewing machine. It is finer (usually 40 weight), it comes on large cones instead of small spools, and it is spun to run through loopers at 1,300-plus stitches per minute without shredding. Based on thousands of buyer reviews and what sewing forums consistently recommend, here are the cones worth buying.
TL;DR: American & Efird Maxi-Lock is the industry default and my top pick (one 3,000-yard cone runs ~$5-7). Coats & Clark SureLock 4-cone set (~$15-20) is the easiest way to match four threads at once. New Brothread 4 large cones (~$25-30) is the best value for high-volume sewing, and Mandala Crafts 4-pack (~$15-18) is a solid budget pick.
At a Glance, Our Scores
| Pick | Best for | Our score | Typical price | Buy |
|---|---|---|---|---|
| American & Efird Maxi-Lock | Best overall | 9.4/10, the thread serger manufacturers use to demo their machines | ~$5-7 per cone | Check Price on Amazon |
| Coats & Clark SureLock 4-Cones | Easiest color matching | 8.8/10, consistent, widely available four-packs | ~$15-20 | Check Price on Amazon |
| New Brothread 4 Large Cones | Best bulk value | 8.7/10, 5,500 yards per cone, 200+ bought monthly | ~$25-30 | Check Price on Amazon |
| Mandala Crafts 4-Pack | Best budget cones | 8.3/10, decent for the price, color range varies | ~$15-18 | Check Price on Amazon |
| Gutermann Toldi-Lock | Premium option (limited US availability) | 8.5/10, excellent quality, hard to find stateside | ~$8-10 | Not available on Amazon |
Prices move constantly on Amazon, every “Check Price on Amazon” link below takes you to the live listing.
Quick Picks
- Best overall: American & Efird Maxi-Lock. It is what dealers use to set up and demonstrate sergers, so it is the safest cone you can thread through any machine.
- Best for matching four threads: Coats & Clark SureLock 4-cone sets. Buy one set and your needles and both loopers match.
- Best bulk value: New Brothread 4 large cones. Each cone holds 5,500 yards, so this set lasts through serious project volume.
- Best budget pick: Mandala Crafts 4-pack. Fine for casual serging, though buyers report more color-to-color variation.
Detailed Reviews
1. American & Efird Maxi-Lock, Best Overall
Maxi-Lock is the default recommendation for a reason. American & Efird makes the thread that serger manufacturers themselves use to test and demonstrate machines in stores. If a dealer is showing you a brand-new serger, odds are it is threaded with Maxi-Lock. That tells you everything about its consistency from the first yard to the last.
It is a 100% spun polyester, 3,000 yards on a standard cone, and it runs clean through loopers with minimal lint. Owners report that switching from a bargain cone to Maxi-Lock fixed skipped stitches they had blamed on tension for months. You buy it one cone per color, which is actually the economical way: one cone of black, one of white, and one of a neutral gray cover about 90% of home serging.
Good
✓ Industry-standard consistency; sets and holds tension easily
✓ Very low lint at high speed, which keeps loopers cleaner
✓ 3,000 yards per cone lasts a long time for home use
✓ Used by serger manufacturers for demos, so it plays well with every brand
✓ Huge color range available across listings
Watch out for
✕ Sold as single cones, so matching four threads means buying four cones
✕ Individual cones cost more per yard than bulk four-packs
✕ Popular colors occasionally sell out
2. Coats & Clark SureLock 4-Cones, Best for Matching Threads
Coats & Clark is the other legacy name in American thread, and SureLock is its serger line. The big advantage here is packaging: four 3,000-yard cones of the same color in one purchase. If you do a lot of visible overlocking (knit garments, activewear, home decor), matching all four threads is what makes seams look professional instead of cobbled together.
It is a 40-weight 100% spun polyester, the same general spec as Maxi-Lock, and buyers say it runs smoothly on Brother, Singer, Juki, and Janome sergers. It is also the easiest of these to find at big-box craft stores, so you can replace a cone on a Sunday afternoon instead of waiting on shipping.
Good
✓ Four matching cones in one purchase, ideal for 4-thread overlock
✓ Long-established brand with consistent dye lots
✓ Runs clean on all major home serger brands
✓ Easy to find locally at craft stores when you run out
Watch out for
✕ Four-pack pricing makes it pricier than budget brands per set
✕ Some buyers note occasional lint on darker colors
✕ Color selection in four-packs is narrower than single-cone lines
3. New Brothread 4 Large Cones, Best Bulk Value
New Brothread has quietly become one of the highest-volume thread sellers on Amazon, and this set is why. Each cone holds 5,500 yards of 40S/2 spun polyester, which is nearly double the yardage of a standard Maxi-Lock cone. For a quilter or garment sewist running a serger every week, that yardage difference is real money.
Buyer reviews (thousands of them) consistently say it runs without breaking or fraying on Brother, Babylock, Janome, and Juki machines, including commercial-speed work. The 30-color range is a bonus for anyone who likes matching thread to fashion fabric. It is not quite as refined as Maxi-Lock, but at this price per yard, it does not need to be.
Good
✓ Outstanding yardage: 5,500 yards per cone, 22,000 yards per set
✓ Strong reviews for high-speed, break-free running
✓ 30 color options, more than most budget lines
✓ Colors are designed to coordinate with major thread color charts
Watch out for
✕ Slightly more lint reported than premium brands on very long runs
✕ Cones are tall, so check they fit under your serger’s thread stand
✕ Newer brand, so long-term dye-lot consistency is less proven
4. Mandala Crafts 4-Pack, Best Budget Cones
Mandala Crafts is a craft-supply brand that has carved out a spot with affordable, decent-quality notions. This four-pack of 40S/2 polyester cones (6,000 yards each, 24,000 yards total) is one of the cheapest ways to load a serger. For a beginner who just bought their first overlock machine and is still learning to thread loopers, burning through budget thread is smarter than wasting premium cones on practice seams.
Owners report it sews well on major serger brands and handles both stretch and non-stretch fabric. The trade-off is consistency: reviews are good overall but less uniformly glowing than the premium picks, and some buyers mention color variation between cones in a set.
Good
✓ Very low price per yard for genuine serger-weight thread
✓ 24,000 yards per set lasts through a lot of practice
✓ Works fine on all major home serger brands per buyer reports
✓ Good starter pack for a first serger
Watch out for
✕ Reviews are more mixed than premium brands
✕ Some color variation reported between cones
✕ Not the pick for heirloom garments or visible topstitching
5. Gutermann Toldi-Lock, Premium Pick (Limited US Availability)
Gutermann is Germany’s premium thread house, and Toldi-Lock is its dedicated serger line. Everything about it is excellent: even dye, clean running, strong seams. If you can find it at a European notions shop or a specialty retailer, it is absolutely worth trying.
The problem is US availability. We could not find a genuine Toldi-Lock listing on Amazon at the time of writing, and grey-market sellers mark it up hard. For most American sewists, Maxi-Lock delivers 95% of the quality at a fraction of the hassle. Buy Toldi-Lock if you stumble across it at a good price, but do not chase it.
Good
✓ Genuine premium quality, even tension from a great manufacturer
✓ Excellent color depth and dye consistency
✓ Low lint, clean looper running
Watch out for
✕ Very hard to find in the US; no Amazon listing we could verify
✕ Expensive when available through importers
✕ Maxi-Lock is easier to get and nearly as good
What to Look For When Buying
Weight and material. Serger thread is typically 40 weight 100% spun polyester. Polyester matters because it has the stretch and strength to survive looper friction at speed. Cotton serger thread exists, but it produces more lint and breaks more often on fast machines.
Cones, not spools. A serger drinks thread. A standard sewing spool holds 100-500 yards; these cones hold 3,000-6,000 yards each. Cones also feed from the top on a thread stand, which is how sergers are designed to pull thread.
Lint is the hidden cost of cheap thread. Bargain cones that look fine on the shelf can shed enough lint to pack your loopers and tension discs in a single afternoon. Cleaning that out costs you more time than the savings were worth. Stick to brands with a track record.
Buy cones per project, not per whim. For a 4-thread overlock you need four cones of the same color. White, black, and gray cover most garments. Beyond that, buy project colors as you need them; serger thread does not expire, but a shelf of 40 colors you never touch is money sitting still.
Frequently Asked Questions
Can I use regular sewing machine thread in my serger?
You can in a pinch, but you should not make a habit of it. All-purpose thread is thicker and comes on short spools that run out mid-seam. It also creates more lint and drag in the loopers. Dedicated serger thread is cheaper per yard anyway.
Why does my serger skip stitches?
Nine times out of ten, it is thread, tension, or a dull needle, in that order. Try a quality cone like Maxi-Lock first, then rethread from scratch, then put in a fresh needle. If the problem survives all three, then start suspecting the machine.
How many cones do I need?
A 4-thread overlock needs four cones. A 3-thread overlock needs three. Most beginners start with white, black, and a mid gray, then add colors per project.
Does serger thread go bad?
Not really, but it does get dusty and UV-faded if you leave cones sitting in sunlight. Store them in a closed cabinet or under cone covers and they will sew fine for years.
Is expensive serger thread worth it?
For visible seams and high-speed sewing, yes. The difference between a premium cone and a bargain cone shows up as fewer skipped stitches, less lint in the machine, and fewer mid-seam breaks. For practice and muslins, budget cones are perfectly fine.