Best Serger-Coverstitch Combo Machines: Is One Machine Better Than Two?
A combination machine can overlock raw edges and create professional-style knit hems. The hidden buying question is how often you will have to convert it between those jobs—and whether you can tolerate that interruption.
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Start with the bernette 68 AIRLOCK: a documented combo model with air-assisted looper threading and a 130 mm right-side workspace.
Check PriceChoose a combo for space; choose two machines for uninterrupted workflow
One combo machine is compelling when space is limited and you can finish several seams before changing to cover hems. Two dedicated machines are easier to live with if you switch between overlocking and coverstitching repeatedly during every garment. Conversion is a real workflow step, not a one-button mode switch.
As an Amazon Associate, we earn from qualifying purchases. This is a documentation-based buying guide, not a hands-on test. We verified the model capabilities against manufacturer pages; sewing quality and conversion times were not independently measured.
First, make the machine-count decision
A serger trims fabric edges while forming overlock seams. A coverstitch machine forms stretchy hems without trimming the edge in the same way. A combo offers both stitch families in one chassis, often with chain and safety stitches too. That does not mean it performs all operations at once or eliminates conversion.
| Decision factor | One combination machine | Separate serger + coverstitch |
|---|---|---|
| Space | One footprint, one primary machine station | Two footprints, plus thread cones and accessories |
| Switching tasks | Change stitch setup, needle positions, threading and/or knife configuration as the manual directs | Move the project to the other already-threaded machine |
| Buying cost | One machine purchase; premium combo features may be costly | Two purchases; cost depends heavily on chosen models |
| If service is needed | Both functions may be unavailable during service | One machine may remain usable |
| Best workflow | Batch all overlock seams, then all hems | Alternate between seam finishing and hemming as needed |
Two combination machines worth comparing
1. bernette 68 AIRLOCK — for easier looper threading and generous workspace
Bernette documents 2-, 3-, 4- and 5-thread stitch configurations; overlock, cover, chain and combination stitches; air threading for the loopers; 130 mm to the right of the needle; and a slide-on table. Its 31 documented stitches include four- and five-thread safety stitches, and its maximum specified sewing speed is 1,300 stitches per minute.
Who should consider it: sewists who expect frequent coverstitch use and value threading assistance and workroom. What it does not solve: conversion still involves a distinct setup. Air threading the loopers does not mean the machine automatically moves needles, changes stitch plates, or configures every thread path.
Manufacturer source: bernette 68 AIRLOCK official specifications. Bernette also publishes model-specific conversion tutorials through its product and dealer support pages.
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2. JUKI MO-735 — for broad stitch coverage in a mechanical combo
JUKI lists 2/3/4/5-thread overlocking, chain stitching, five-thread safety stitching, and two- or three-needle coverstitching. The official US listing documents 24 stitch patterns, differential feed from 0.7 to 2.0, and a maximum speed of 1,500 stitches per minute.
Who should consider it: a buyer comfortable learning the machine's mechanical conversion process who wants one machine for overlock and cover hems. Tradeoff: it does not advertise the same automatic air-looper threading feature as the bernette 68. Do not interpret its higher rated maximum speed as proof of better seam quality.
Manufacturer source: JUKI MO-735 official product specifications. JUKI also lists the MO-735N in its international support catalog; confirm the exact regional model and manual rather than assuming every suffix is identical.
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Side-by-side: what the specifications actually tell you
| Feature | bernette 68 AIRLOCK | JUKI MO-735 |
|---|---|---|
| Stitch families | Overlock, cover, chain, combination/safety | Overlock, cover, chain, safety |
| Documented thread range | 2–5 threads | 2–5 threads |
| Rated maximum speed | 1,300 stitches/min | 1,500 stitches/min |
| Differential feed | Present; consult manual for settings | 0.7–2.0 |
| Looper threading aid | Air-assisted | Conventional documented threading |
| Right-side working space | 130 mm | Not compared: no equivalent verified manufacturer measurement used here |
| Coverstitch widths | 2.8 / 5.6 mm | 2.5–5 mm in JUKI's MO-700-series brochure |
Specifications are manufacturer claims. They do not establish which machine produces more consistent stitches on your fabric, is quieter, or converts faster in practice. Accessory bundles and model suffixes may vary by market.
The conversion burden: six things to ask for a dealer demonstration
Ask the seller to show an overlock → coverstitch → overlock cycle using the exact machine you would receive. Watch the whole process rather than only the final stitch sample.
- Needle changes: Which needles must be inserted, removed or repositioned?
- Thread paths: Which threads need rerouting, and how easy are the guides to see?
- Knife and stitch plate: What must be moved or changed, and does the machine prevent unsafe operation if set incorrectly?
- Presser foot and attachments: Is a different foot or table insert required?
- Tension and differential feed: Which settings must be changed, and can your preferred settings be reproduced reliably?
- Return to serging: Is converting back as straightforward as converting to coverstitch?
A dealer demonstration is more meaningful than a generic claim that conversion is “easy.” The actual burden depends on the machine, the chosen stitches and your familiarity with its threading diagrams.
Three project patterns—and the machine setup that fits
Batch garment construction
Overlock the shoulder and side seams of several T-shirts, then convert once to coverstitch the hems. This workflow makes a combo easier to justify because it reduces repeated conversions.
One-off repairs and alterations
A single garment may need a serged edge, then a cover hem, then another serged section. If you frequently alternate, two machines ready to sew may be more efficient.
Occasional knit sewing
If you only need a few hems a year, evaluate whether a dedicated coverstitch machine is necessary at all. Depending on the fabric and finish, a regular sewing machine with a suitable stretch stitch or twin needle may meet your needs. It will not replicate every coverstitch construction.
What to inspect beyond the headline stitch count
- Local service and parts: Confirm a technician can support the exact model and that accessories are available.
- Included coverstitch hardware: Check the stitch plate/insert, feet, extension table, needles, and threading aids against the seller's package list.
- Fabric tests: Ask to sew the actual lightweight jersey, rib knit, or sweatshirt fabric you use, including seam intersections.
- Needle system: Follow the exact manual; do not substitute needles simply because they fit physically.
- Thread cost and storage: Multiple cones and color changes are part of combo ownership.
- Manual and support: Verify the supplied manual matches the machine's model suffix and market.
Final decision: which combo should you buy?
Choose the bernette 68 AIRLOCK if air-assisted looper threading, a documented roomy coverstitch work area and its included table are priorities. Consider the JUKI MO-735 if you want broad mechanical overlock/coverstitch capability and are comfortable with its conversion procedure. Neither is automatically better on finished-stitch quality without direct comparative tests.
Choose two dedicated machines instead if you repeatedly switch functions while making each garment and have space for both. For many serious knit sewists, reducing conversion interruptions is more valuable than reducing the machine count.
Manufacturer documentation
- bernette 68 AIRLOCK product specifications and accessories
- JUKI MO-735 product specifications and accessories
- JUKI international overlocker manuals and model list
No independently measured conversion time, stitch quality, noise level, long-term durability or current stock claim is made. Amazon search links are model-specific; results may include accessories or different versions, so verify the exact item before ordering.