The number on your industrial machine's plate: which needle it means

DBx1, 16x231, 287 WH and 1738 (A) are printed together on one current listing at SCHMETZneedles.com, the US store run by SCHMETZ's North American importer, Euro-notions. The listing gives "CANU: 14:25 1", then DBx1, 16x231, 287 WH and 1738 (A). CANU is SCHMETZ's catalog number for the needle. If your plate or manual gives any of those four names, open the listing titled 16x231.

A plate that says DPx5, 135x5 or 1955 points to the listing titled 134 (R), which prints 135x5, SY 1955 and DPx5 beside it.

The letters after a number matter. Plain 287, 287 WH and 287 WK are on different listings, and so are 1738 (A) and 1738 ES. Names that look alike can be different needles too: DBx1 and DBxK5 are two systems, not two spellings of one. The table maps each name to its listing. The sections after it cover the traps.

Each row gathers the names printed together on one SCHMETZneedles.com listing. Find the name from your plate or manual in the first column. The store has 27 standard industrial listings, plus about 150 more in a separate Special Order Industrial Needles collection. Rows from that second collection are marked "special order". The store's search box covers both. The listings sell needles by the hundred (the SERV 7 long-arm needles 10 to a chip), and the special-order listings say those needles can't be returned or exchanged. Settle the system before you order.

• Plain 287, 287 WH and 287 WK carry different catalog numbers. Plain 287 is on 34 (R), beside 16x1 and TFx1. 287 WH is on 16x231, and on 16x95 from 120/19 up. 287 WK has its own special-order listing, which calls it similar to 287 WH but typically specified for older machines. The SCHMETZ FAQ says older Barudan embroidery machines were set up for 287 WK, and newer ones for DBxK5.
• 1738 needs its letters too. 1738 (A) is on the 16x231 listing. 1738 ES is on DBxK5 KK, a short-point, short-shank needle that its listing says is for commercial embroidery machines. 1738 (A) LR is on 16x230 R TW (special order, CANU 14:25 AX1), which its listing calls similar to 16x231 but with a leather point. If your plate says only 1738, find the full name in the manual before you buy.
• 287 WH and 1738 (A) are split by size. The 16x231 listing runs from 60/8 to 110/18. The 16x95 listing, which calls 16x95 "the larger size designation of 16x231," runs from 120/19 to 140/22. If your manual allows 120/19 or heavier, that is where those two names continue. The standard 16x95 listing doesn't print DBx1, though its special-order SES version (CANU 14:20EB1) does.
• DBx1 SES and DBx1 SERV 7 also appear on 134 listings. DBx1 SES is printed on 16x231 SES (CANU 14:25 EB1), on 16x95 SES (CANU 14:20EB1) and on 134 SES (CANU 20:05EB1), which also prints 135x5 SES and DPx5 SES. DBx1 SERV 7 is on 16x231 SERV 7 (CANU 14:25 17) and on the special-order 134 (R) SERV 7 (CANU 20:05 17). The shanks differ: the long-arm listings give 16x231 SERV 7 a 1.63 mm shank, and 135x5 SERV 7, which has the same catalog number as 134 (R) SERV 7, a 2.0 mm shank. No listing explains the overlap. Going by the catalog numbers, and by the SCHMETZ FAQ's answer that DBx1 is "also known as 16x231," the listings to open for a DBx1 machine are the ones whose CANU starts 14:25. Ask the seller before you buy a box of 100 from a listing that doesn't also print 16x231.
• In 120/19 and heavier, the two needle makers point different ways. SCHMETZ puts the heavier 287 WH and 1738 (A) sizes on 16x95 (CANU 14:20). Groz-Beckert, another needle maker, adds DBX1 to the label of its standard 134 needles from 120/19 up, and not below. For a heavy size, go by the needle line in your machine's manual and check with the seller.

• DBx1 and DBxK5. The SCHMETZ FAQ calls them "two different systems" that look similar: DBx1 for lightweight lockstitch machines, DBxK5 for embroidery machines. Groz-Beckert's embroidery catalog says the two differ only in point length and eye size: DB x K5 has the larger eye and a standard-length point, DB x 1 a standard eye and a long point. It adds that DB x 1 is also often used in embroidery, and is suited, particularly in size Nm 55, to very small lettering and sequined embroidery. If your embroidery machine's manual says DBxK5, search for DBxK5.
• DCx1 and BLx1. The SCHMETZ FAQ gives DCx1 a 2.02 mm shank and a 28.6 mm length, and BLx1 a 1.64 mm shank and a 33.9 mm length. It says neither would fit the other's needle holder.
• BLx1 and 16x231. These share a shank and length (1.63 mm and 33.9 mm in the FAQ's answer on this pair) and differ mainly in the scarf: BLx1's is longer and flatter, for zigzag. Asked about a Riccar Lock RL-340, the FAQ said 16x231 could be used instead of BLx1. That answer covers that machine, not every machine that takes BLx1.
• 16x231 and 135x5. The store's listings say both are generally used in single-needle lockstitch machines, but the long-arm versions have different shanks: 1.63 mm for 16x231 SERV 7 and 2.0 mm for 135x5 SERV 7. The store says the 135x5 one is used by long-arm machines like Gammill, Handi-Quilter, Nolting, A1 and APQS. A machine maker can list both for one machine: JUKI's spec for its DDL-8700 gives DB×1, #9 to #18, and 134 (Nm90) on the same needle line. Buy the system your own machine's manual or spec names.
• B-27 and DCx1. SCHMETZ keeps them on separate listings: B-27 with DCx27 (CANU 03:36 1), and DCx1 with 81x1 (CANU 03:33 1). Groz-Beckert labels its B 27 needles B27/81X1/DCX27/DCX1, so the two makers group these names differently. Go by the name in your overlock's manual, and ask the machine's dealer before using one in place of the other.
• Household needles. The SCHMETZ FAQ gives every household 130/705 H needle a 2.04 mm shank with a flat side, against 1.63 mm for 16x231. It is a separate system. For household sizes and points, see how to read 130/705 H and 90/14.

• Read the needle line in the manual, with the full model number. The SCHMETZ FAQ answers a question about a "Juki 5550 DDL" with DBx1, also known as 16x231. JUKI's own manual for the DDL-5550N-7 and DDL-5550-7 adds an exception: the DDL-5550A-7 and DDL-5550NA-7 take DA x 1. DAx1 is on the 88x1 listing, not the 16x231 one. In that manual the needle line is in section 4, "Attaching the needle".
• Use the system the machine maker names. The SCHMETZ FAQ says you need the needle system the machine manufacturer specifies, and that a system offered in the size you want can still be the wrong length or diameter for your machine.
• Don't count on an old needle to tell you. The SCHMETZ FAQ says its needles are stamped only with the SCHMETZ name and the size, so a loose SCHMETZ needle won't show its system. A caliper can rule a system out but not in: the FAQ gives 16x231 and BLx1 the same shank and length.
• If your name isn't among the 27 standard listings, search the store or open its Special Order Industrial Needles collection. DHx1 is an example. The SCHMETZ FAQ says DHx1, also known as 24x1, has been discontinued, yet the store has a special-order listing for 24x1 and DHx1 (CANU 02:65), and Groz-Beckert's catalog shows a 24X1/2060/DHX1 needle in 75/11. Some systems are gone: the FAQ says SCHMETZ no longer makes 443 W and has nothing to substitute. If a name is in neither collection, ask the machine maker's parts department.

The main table is SCHMETZ's grouping as printed on SCHMETZneedles.com. That store belongs to Euro-notions, Inc., SCHMETZ's North American importer. The catalog numbers are SCHMETZ's; the listing text and FAQ answers are the importer's. Groz-Beckert, another needle maker, prints its own grouping on each product in its online catalog. For the same systems, the two mostly line up. The differences are in the last column.

An older Groz-Beckert information sheet, dated 2012, drew 1738 and DB x 1 as separate systems. It gave both a standard eye and a long R point, and its chart showed 1738 with lower bending resistance. So if your plate says a bare 1738, or a name that sits on two listings, let the machine's manual decide before you buy a box of 100.

The bobbin is a separate question with its own traps. See which bobbin class your machine takes.