A dedicated coverstitch machine — not a combination unit — with a separate needle threader and a looper threading mechanism. One reference on all six markets we checked.
The bottom line The right answer for a second machine, provided you understand it is not an overlocker.
Hands-on testing pending. Everything below is either a manufacturer
specification, cited as such, or something we verified ourselves.
What we verified. The reference B07FM7WCDH designates this machine on all
six Amazon stores we checked, confirmed on EAN.
A warning about the listing itself. The German product title reads
“Bernette B42 Overlock Overlock Overlock Overlock Overlock…” — the word repeated
eight times. That is keyword stuffing on the seller’s side, and it matters here
because the b42 is not an overlocker. Someone searching for an overlocker
will find this machine, and it will not do the job they are buying it for. We
would rather say that on the review page than let the listing do the talking.
What the manufacturer states. A coverstitch machine described as suitable
for private and professional use, with a separate needle threader and a looper
threading mechanism, LED work lighting, an extended work surface, and a starter
set of feet, needles and accessories. Listed weight 8.62 kg. Bernette states it
handles fine knits, stretch fabrics and heavier materials.
Why the threading mechanism is the headline. Loopers are the reason
coverstitch and overlock machines sit in cupboards. A machine with a mechanism
for threading them, rather than tweezers and a diagram, is a machine that gets
switched on — and that is worth more than any stitch specification on this type
of product.
Where we would look before buying. How cleanly it handles the join where a
coverstitch hem meets a bulky overlocked side seam. It is the moment these
machines skip stitches, and it happens on almost every T-shirt.
What we like, and what we don't
Strengths
Dedicated machine — no conversion time between overlocking and hemming
Looper threading mechanism, which is the operation that puts people off
One reference on all six markets we checked
Compromises
A second machine on the table, and 8.6 kg of it
Amazon's listing title is padded with the word 'Overlock' repeated — it is not an overlocker
Specifications
Type
Dedicated coverstitch
Threading
Separate needle threader plus looper threading mechanism
Lighting
LED
Included
Presser feet, needles, threader and accessories (manufacturer)
Weight
8.62 kg
Questions people actually ask
Is this an overlocker?
No, and the Amazon title is actively misleading on this point — it repeats the word 'Overlock' several times. A coverstitch machine makes the twin-needle hem you see on bought T-shirts. It does not trim and enclose a seam edge. If you own neither, buy the overlocker first.
Dedicated machine or a combination unit?
If you already own an overlocker, dedicated, every time. Combination machines are excellent value on paper, but converting between overlocking and coverstitching takes long enough that people stop alternating — which means they stop doing one of the two operations on the same garment.
Overlock + coverstitch + chainstitch · UK and US only
A combined overlock and coverstitch machine, proven on the UK and US stores only. On the German store the same search returns a set of presser feet, which is the more useful warning.
Best for: A UK or US buyer who wants both operations without two machines on the table
A well-documented coverstitch machine running two to five threads, with a 155 mm throat and differential feed. Five European markets; on amazon.com the search returns an accessory, not the machine.
Best for: Hemming knits properly, and anyone who has outgrown a twin needle on a normal machine
A dedicated coverstitch machine — not an overlocker — on one reference across all six markets. Janome publishes almost nothing about it, and we are not filling the gap from memory.
Best for: Someone who already owns an overlocker and wants twin-needle hems on knits