DIN 431 Pipe Nuts (G Thread)
DIN 431 pipe nuts, G 1/8 to G 6 — the wide hex union nut that clamps parallel pipe-thread fittings together — with the collected per-size tables: across corners e, height m and across flats s for every G size.
Last updated: 2026-11
Specifications
DIN 431 is the wide hex nut for parallel pipe threads: it runs onto a G-threaded fitting, nipple or valve body and pulls the joint tight, which is why it is the standard union and back-nut on plumbing manifolds, pneumatic and hydraulic blocks, lamp and conduit fittings. The hex is flatted for a normal spanner, and the collected tables give the three numbers a housing or wrench designer needs for every size from G 1/8 to G 6: across corners e (min), nut height m (max/min) and across flats s (min and max=nominal). The source also prints approximate mass per 1000 units — with a ① marker of no legend and "-" where no value is tabulated — reproduced verbatim and disclosed. Parenthesized sizes are the non-preferred series as printed. Finishes (the raw nut is commonly zinc-plated or nickel-plated for water work) and materials are not printed by the collected specification and stay per RFQ.
| Standard | DIN 431 — pipe nuts with G (ISO 228 parallel) thread, wide hex union/back nuts |
|---|---|
| Series | G 1/8 – G 6 (six source column groups; parenthesized sizes are the non-preferred series as printed) |
| Tabulated geometry | Per size: across corners e (min, 19.85–209.5 mm), height m (max/min), across flats s (min and max=nominal, 17.57–190 mm) |
| Source mass row | "per 1000 units≈kg ①" as printed — ① has no legend on the page; "-" where not tabulated |
| Function | Pulls G-thread fittings and nipples together; the standard back-nut on threaded pipe and conduit work |
| Materials / finish | Not tabulated by the collected specification — per RFQ |
| Attribute | G 1/8 | G 1/4 | G 3/8 | G 1/2 |
|---|---|---|---|---|
| e — min | 19.85 | 22.78 | 29.56 | 37.29 |
| m — max | 6.48 | 6.48 | 7.58 | 8.58 |
| m — min | 6 | 6 | 7 | 8 |
| s — min | 17.57 | 20.16 | 26.16 | 33 |
| s — max=nominal size | 18 | 21 | 27 | 34 |
| per 1000 units≈kg ① | - | - | 26.1 | - |
| Attribute | (G 5/8) | G 3/4 | (G 7/8) |
|---|---|---|---|
| e — min | 37.29 | 39.55 | 45.2 |
| m — max | 8.58 | 9.58 | 9.58 |
| m — min | 8 | 9 | 9 |
| s — min | 33 | 35 | 40 |
| s — max=nominal size | 34 | 36 | 41 |
| per 1000 units≈kg ① | - | 43.6 | 54 |
| Attribute | G 1 | (G 1 1/8) | G 1 1/4 |
|---|---|---|---|
| e — min | 50.85 | 55.37 | 60.79 |
| m — max | 10.58 | 10.58 | 11.7 |
| m — min | 10 | 10 | 11 |
| s — min | 45 | 49 | 53.8 |
| s — max=nominal size | 46 | 50 | 55 |
| per 1000 units≈kg ① | 81.3 | 95 | 117 |
| Attribute | G 1 1/2 | (G 1 3/4) | G 2 |
|---|---|---|---|
| e — min | 66.44 | 76.93 | 82.6 |
| m — max | 12.7 | 13.7 | 13.7 |
| m — min | 12 | 13 | 13 |
| s — min | 58.8 | 68.1 | 73.1 |
| s — max=nominal size | 60 | 70 | 75 |
| per 1000 units≈kg ① | 134 | 213 | 277 |
| Attribute | (G 2 1/4) | G 2 1/2 | G 3 |
|---|---|---|---|
| e — min | 93.56 | 104.86 | 116.16 |
| m — max | 16.7 | 16.7 | 19.84 |
| m — min | 16 | 16 | 19 |
| s — min | 82.8 | 92.8 | 102.8 |
| s — max=nominal size | 85 | 95 | 105 |
| per 1000 units≈kg ① | 378 | 449 | 554 |
| Attribute | G 4 | G 5 | G 6 |
|---|---|---|---|
| e — min | 149.72 | 183.06 | 209.5 |
| m — max | 22.84 | 22.84 | 25.84 |
| m — min | 22 | 22 | 25 |
| s — min | 132.5 | 162.5 | 185.4 |
| s — max=nominal size | 135 | 165 | 190 |
| per 1000 units≈kg ① | 1 040 | 1 330 | 1 850 |
Materials
- Material and finish specified per RFQ — state the medium (water, air, oil) at quotation
Ordering & documentation
Documents
Shipments are backed by Mill Test Certificate (MTC), Dimensional Report, Salt Spray Test Report on request, with full batch traceability from raw material to finished product. Quality management follows the owner-confirmed compliance list: ISO 9001:2015, RoHS, REACH. Exact document sets are confirmed on the order.
Quotation
- The fastener family (DIN 431 Pipe Nuts (G Thread)) plus the standard designation from your drawing — DIN / ISO / JIS / ASTM / ANSI, or a drawing for custom parts.
- Size (diameter and length), thread type (metric or inch), property class or grade, and coating or finish.
- Quantity per size and your target delivery date.
- Destination country, and any required documents (for example a mill test certificate) so the quote includes them.
Sample & supply
Minimum order quantity is 10,000 pieces. Stock items run 3–7 days. Quantities or variants outside the standard range are confirmed at quotation.
Storage & shipping
Parts are packed for export and shipped factory-direct to buyers in Europe, Asia, the Americas and the Middle East. Store fasteners dry and protected until installation, and keep coated parts in their packaging until use; specific packing and preservation requirements can be stated on the order and confirmed at quotation.
Frequently asked questions
Which DIN 431 size matches my pipe fitting?
Match the thread, then check the wrench. G sizes name the nominal bore of the pipe thread, not the nut: a G 1/2 pipe nut runs on any G 1/2 parallel-thread fitting regardless of brand, because the thread form is the ISO G series the whole plumbing and pneumatic world shares. What does vary by supplier is the hex — read the collected table's s column against your spanner stock (G 1/2 flats at 34 mm, G 3/4 at 36 mm, G 1 at 46 mm) and the m column against the clearance in your housing: these nuts are taller than the thin ISO 4035-style hex nuts some assemblies try to substitute. Mind the non-preferred series — the parenthesized sizes in the tables — and confirm the sealing method separately: a parallel G joint seals on a seating washer, an O-ring or jointing compound, not on the thread flanks.
What is the MOQ and lead time for this nut type?
The minimum order quantity is 10,000 pieces. Stock items ship in 3–7 days; non-stock items are confirmed at quotation. Common sizes in this nut type are widely stocked; confirm the exact schedule against quantity and size mix at quotation.
Request a Quote
Get factory-direct pricing from the manufacturer.
What to include in your inquiry
- ✓ Standard and property class (e.g. DIN 912, ISO 4762, class 8.8) — or a drawing for custom parts.
- ✓ Sizes, lengths and thread type (metric or inch).
- ✓ Quantity per size and your target delivery date.
- ✓ Destination country, plus any coating or finish requirement.
- ✓ Any documents you need with the shipment (e.g. mill test certificate) so the quote includes them.
- ✓ Your inquiry goes straight to the factory team by email and gets a reply within 24 hours.
- ✓ Factory-direct pricing
- ✓ Standard and custom specifications
- ✓ Factory-direct export to buyers in Europe, Asia, the Americas and the Middle East
- ✓ Full fastener family support