Best Thread for Bernina Sewing Machines: What Bernina’s Manuals Name and Owners Use

Our verdict

Top Picks

Bernina’s manuals answer the brand question. The B 495 manual says the factory tension uses “Metrosene/Seralon thread size 100/2 (Mettler, Switzerland)”, and the B 790 PRO manual says its “embroidery designs are programmed with the Isacord 40 thread brand.” Each pick’s Bernina tie is named in its review.

Price tier legend: $ = entry level, $$ = mid-range, $$$ = premium, relative to the threads in this guide, per listing, not per yard.

Compare the picks

The nine threads side by side

Weights are each maker’s own number (Mettler and Gütermann “No.”, Aurifil “wt”); they don’t compare across lines. “Listing” means the Amazon listing; other figures are the thread maker’s.

What Bernina Says About Thread

The factory tension thread. The B 495, B 325 and B 790 PRO manuals all name Metrosene/Seralon 100/2, and the B 495 adds: “When using other sewing threads, the optimal upper thread tension may vary.” Mettler’s partner page goes further: “BERNINA recommends Mettler threads in the machine instruction manuals”.

Fibre by job. In the B 790 PRO manual, cotton suits quilts but not seams that must be particularly hard-wearing, and polyester is “recommended where a strong and elastic seam is required”. Bernina’s B 820 manual answers uneven stitches with “Use quality threads (Isacord, Mettler, Gütermann)”.

Weight by use. Bernina of America’s sewing workbook lists 50 wt for “General construction, piecing, bobbin thread, quilting” and 40 wt for “General construction, quilting, embroidery”.

Embroidery. Bernina’s embroidery workbook says “Most designs are digitized for 40-weight” and “use a high quality 60-wt thread in the bobbin”. The Bernina blog names Mettler lines by job: “a universal sewing thread (Seralon) for all types of fabric and stitch”, “an elastic sewing thread (Sera Flex)” for stretch fabrics, and “an embroidery thread with high tear strength and beautiful shine (PolySheen)”.

How We Tied Each Thread to a Bernina

What decided the picks

• A Bernina source or a named Bernina owner: a manual, bernina.com, the Bernina blog, WeAllSew (Bernina USA’s blog), or an owner who names the machine.
• Fibre, weight, needle and colours from the thread maker (OESD for Isacord), listing figures labelled.
• New and in stock on Amazon when we checked on 10 November 2026, seller named in each review.

No pick is claimed to suit every Bernina; each review names any machine its source covers.

Threads we left out and what Bernina owners report

Threads we left out

• Mettler bobbinette and Cordonnet: Bernina sources name both (Cordonnet Foot #11); neither turned up on Amazon in our searches.
• Sulky Rayon 40: the one Bernina owner we found who mentions it names the brand, not the line.
• Kits whose titles call them Bernina-“compatible”: a listing’s claim, with no Bernina source.

What Bernina owners report

In an r/Bernina thread, the poster’s household 880 PLUS broke top thread on “cheap coats and Clark”, sewed “great” with “white cotton mettler”, then broke again about half a bobbin into “aurifil cotton”. Replies point to the needle or threading; MaeByourmom, an 820 owner, says “the only time I have trouble with it is when it’s threaded wrong or too fast.”

Detailed Reviews

Mettler Metrosene, Best All-Purpose

Evidence: No independent test; maker specs. Source: BERNINA B 495 manual.

A Bernina quilt project lists “Sewing Thread Seralon/Metrosene”; the specs below are Mettler’s Seralon figures. We found no independent review or forum owner report naming this spool; we did not grade its Amazon customer reviews.

Specs (linked: 1,097 yd spool, White)

• Fibre: 100% polyester (Mettler)
• Weight: No. 100 (Mettler); 50 wt (listing)
• Needle: Nm 80-90 (Mettler)

Mettler Silk-Finish Cotton 50, Best Cotton for Quilting

Evidence: No independent test; owner reports. WeAllSew (BERNINA USA’s blog), Satomi Hoar on a BERNINA Q 16 sit-down longarm: Silk-Finish Cotton No. 50, spool size not stated.

On WeAllSew, Satomi Hoar writes: “I used Mettler SILK-FINISH COTTON No. 50 for the top and SERACOR polyester No. 120 for the bobbin”, calling Mettler “a great fit with the BERNINA Q 16”. As Bernina’s blog, WeAllSew is not independent. Another WeAllSew post by Julie Bridgeman says it “produces less lint build-up in your machine”.

Specs (linked: 547 yd spool, Black)

• Fibre: 100% mercerized cotton, 3-ply (Mettler)
• Weight: No. 50 (Mettler)
• Needle: Nm 70-80 (Mettler); 80-90 (listing)

Aurifil Mako Cotton 50wt, Best Thin Piecing Cotton

Evidence: No independent test; owner reports. r/quilting, BERNINA 780 owner: Aurifil, weight not named.

In r/quilting, the owner of a “new to me Bernina 780” writes: “I used Aurifil for practice piecing and embroidery and it’s amazing” (weight not named). In the 880 PLUS thread, a reply says “Aurifil always lets you know when a needle is going bad.”

Specs (linked: 1,422 yd spool, Dove)

• Fibre: 100% cotton (Aurifil)
• Weight: 50wt, 2-ply (Aurifil)
• Needle: 80/12 Microtex, Universal, Quilting or Denim (Aurifil)

Aurifil Mako Cotton 28wt, Best for Decorative Stitches

Evidence: No independent test; owner reports. WeAllSew (BERNINA USA’s blog), Quilting with Latinas: Aurifil 28wt on a B 590 E (post’s Used Products list).

In a Bernina WeAllSew post, Quilting with Latinas lists “Top thread: Aurifil 28wt for bold, defined stitches” and “Bobbin: Aurifil 50wt to keep the underside smooth”, with “a Topstitch 100/16 needle” and upper tension “around 3”, on a “BERNINA machine with 9 mm stitch plate” (B 590 E, under “Used Products”).

Specs (linked: 820 yd spool, Chalk)

• Fibre: 100% cotton, 2-ply (Aurifil)
• Weight: 28wt (Aurifil)
• Needle: 90/14 Topstitch, Quilting or Denim (Aurifil); 100/16 Topstitch (WeAllSew)

Gutermann Sew-All, Best Alternative Polyester

Evidence: No independent test; owner reports. r/Bernina, 880 PLUS owner: Gutermann, line not named.

The B 820 table names the brand, not the line. In the r/Bernina 880 PLUS thread, fatedperegrine, who writes “I love my 880plus”, says “I primarily use gutermann and coats and clark” (line not named).

Specs (linked: 1,094 yd spool, Nu White)

• Fibre: 100% polyester (Gütermann)
• Weight: No. 100 (Gütermann)
• Needle: Universal NM 70-90 (Gütermann)

Mettler Seraflex, Best for Stretch Fabrics

Evidence: No independent test; owner reports. WeAllSew (BERNINA USA’s blog), Terrance Williams on a B 790 PRO: Seraflex, colour and spool not stated.

On Bernina’s WeAllSew, Terrance Williams writes: “I used my BERNINA 790 PRO and Seraflex thread from Mettler”, and “When working with the Seraflex thread, you only need to do a straight stitch!” Mettler says it can “stretch up to 65%”.

Specs (linked: 142 yd spool, Black)

• Fibre: 100% PTT (Mettler)
• Weight: No. 120 (Mettler); 50wt (listing)
• Needle: Nm 70-80 (Mettler)

Isacord 40, Best Embroidery Thread

Evidence: No independent test; owner reports. WeAllSew comment, BERNINA 830LE owner: Isacord, weight and colour not named.

On WeAllSew, commenter omalo, “the proud owner of a Bernina 830LE”, writes: “I have learned to use ONLY Isacord thread as other brands break or shred.” In r/quilting, Natural_Parfait_3344, who bought a new Bernina with embroidery, writes “I prefer Isacord”. OESD, which sells it, calls the spool “lint-free, colorfast”.

Specs (linked: 1,000 m spool, 0020 Black)

• Fibre: 100% polyester (OESD)
• Weight: 40 wt (OESD)
• Needle: not published (OESD)

Mettler Poly Sheen 28-Spool Kit, Best Embroidery Colour Set

Evidence: No independent test; maker specs. Source: BERNINA blog and Mettler’s kit page.

The Bernina blog names PolySheen for embroidery, and the same Bernina quilt project lists “Embroidery Thread Poly Sheen (Isacord)”. Mettler’s kit page gives “28 popular colors from every color family” at 200 m each. We found no independent review or forum owner report for it; we did not grade its Amazon customer reviews.

Specs (linked: 28 spools of 200 m)

• Fibre: 100% trilobal polyester (Mettler)
• Weight: No. 40 (Mettler)
• Needle: Nm 65-90 (Mettler)

OESD Bobbin Thread Cone, Best Embroidery Bobbin

Evidence: No independent test; maker specs. Source: OESD product page.

Bernina’s site calls OESD “a subsidiary of the BERNINA Textile Group”, and Bernina’s embroidery workbook says “use a high quality 60-wt thread in the bobbin”. OESD’s page gives polyester and 5,500 yards but no weight. The listing showed no Amazon star rating when we checked.

Specs (linked: 5,500 yd cone, White)

• Fibre: 100% polyester (OESD)
• Weight: 60 (listing)
• Needle: not published

Needles, Lint and Fabric Fit on a Bernina

Needle system. The Bernina blog says “The needle system for all BERNINA household sewing machines is 130/705 H”, and suggests 70/10 or 75/11 for lightweight fabrics, 80/12 or 90/14 for medium and 90/14 or 100/16 for heavy.

Thread to needle. Nancy Prince pairs “80/12 – 50 weight threads”, “90/14 – 40 weight threads” and “100/16 – 30 weight threads and thicker”, noting weight “can vary between manufacturers”. The Bernina blog’s check: let the needle slide down the thread “held at 45 degrees”; if it sticks, go up a size.

Lint. The sewing workbook says “Most bargain-priced threads are usually short staple and will deposit more lint and fuzz into your sewing machine”. Bernina’s embroidery thread page adds: “Be sure to clean the hook area after embroidering with cotton threads.”

Frequently Asked Questions

The manuals we read name Mettler Metrosene/Seralon 100/2 as the factory tension thread and Isacord 40 for the B 790 PRO’s designs.

A Bernina 780 owner called it “amazing”; one 880 PLUS household reported breaks, with replies pointing to the needle.

Bernina’s manuals set the factory tension with Mettler, and the B 820 lists both among quality threads.

Bernina household machines take the 130/705 H system (Bernina blog), and a WeAllSew tutorial uses SCHMETZ Topstitch needles on a Bernina.

Isacord 40 on top, as the B 790 PRO’s designs are programmed with it, and a 60-wt bobbin thread, per Bernina’s workbook.

The bottom line

Final Verdict

For everyday sewing, Mettler Metrosene (check price); for quilting cotton, Mettler Silk-Finish Cotton 50 (check price); for embroidery, Isacord 40 (check price) with the OESD Bobbin Thread Cone. See also our Janome thread guide, sewing machine thread guide, cotton thread picks, thread brands, embroidery machine thread and all needles, pins and thread.

Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.com at the time of purchase will apply to the purchase of this product.