EN 14399-4 Hex Bolts with Large Head (System HV)
EN 14399-4 hexagon bolts with large head for high-strength structural bolting, System HV, M12–M36 — the collected per-size tables: pitch, reference thread length b, d s, e, k, s and r, with the DAST-directive footnote.
Last updated: 2026-11
Specifications
EN 14399-4 is the European structural bolting standard for the HV system: a heavy hexagon head bolt tightened to a controlled preload in steel-to-steel joints, paired with EN 14399 HV nuts and washers and assembled under the DAST directive the collected page cites. The "large head" is the point — a wider, taller hex than the ISO 4014 general-purpose bolt, giving the bearing area and wrenching stability that high-preload field splicing needs. The collected tables run M12 to M36: per size the pitch, the reference thread length b, shank d s with max/min, across-corners e, head height k with tolerance, across-flats s (max=nominal, with min), and the fillet r. The collected page notes the standard replaces DIN 6914 — see the DIN 6914 page in this family for its step-line thread-length presentation. Property classes (HV system pairs 10.9 bolts with class 10 nuts) and finishes are not printed by the collected specification and stay per RFQ; for a structural delivery, state the assembly class (HV), the Slip factor / coating requirements and any CE/EN 15048 or project-specific certification at quotation.
| Standard | EN 14399-4 — hexagon bolts with large head for high-strength structural bolting, System HV; the collected page notes it replaces DIN 6914; head and bearing dimensions acc. to DAST directive (source footnote) |
|---|---|
| Series | M12 – M36 (two source column groups: M12/M16/M20/M22 and M24/M27/M30/M36) |
| Tabulated geometry | Per size: pitch P, reference thread length b, d s (max/min), e (min), k (nominal/max/min), s (max/max=min as printed, min), r (min) — s max 22–60, k nominal 8–23, e min 23.91–66.44 |
| System pairing | System HV bolts pair with EN 14399 HV nuts and washers and a calibrated tightening procedure (DAST directive, per the source footnote); k-class/d-class fit and lubrication are confirmed per order |
| Property classes / finishes | Not tabulated by the collected specification — per RFQ (state class, coating and any CE/documentation requirement explicitly) |
| Attribute | M12 | M16 | M20 | M22 |
|---|---|---|---|---|
| P — Pitch | 1.75 | 2 | 2.5 | 2.5 |
| b — Ref. | 23 | 28 | 33 | 34 |
| d s — Nominal Size | 12 | 16 | 20 | 22 |
| max | 12.7 | 16.7 | 20.84 | 22.84 |
| min | 11.3 | 15.3 | 19.16 | 21.16 |
| e — min | 23.91 | 29.56 | 35.03 | 39.55 |
| k — Nominal Size | 8 | 10 | 13 | 14 |
| max | 8.45 | 10.75 | 13.9 | 14.9 |
| min | 7.55 | 9.25 | 12.1 | 13.1 |
| s — max | 22 | 27 | 32 | 36 |
| min | 21.16 | 26.16 | 31 | 35 |
| r — min | 1.2 | 1.2 | 1.5 | 1.5 |
- Row 2 (b — Ref.): b is printed as a single reference value ('Ref.') per size — the collected page does not tabulate the above/below step-line split its DIN 6914 counterpart prints.
| Attribute | M24 | M27 | M30 | M36 |
|---|---|---|---|---|
| P — Pitch | 3 | 3 | 3.5 | 4 |
| b — Ref. | 39 | 41 | 44 | 52 |
| d s — Nominal Size | 24 | 27 | 30 | 36 |
| max | 24.84 | 27.84 | 30.84 | 37 |
| min | 23.16 | 26.16 | 29.16 | 35 |
| e — min | 45.2 | 50.85 | 55.37 | 66.44 |
| k — Nominal Size | 15 | 17 | 19 | 23 |
| max | 15.9 | 17.9 | 20.05 | 24.05 |
| min | 14.1 | 16.1 | 17.95 | 21.95 |
| s — max | 41 | 46 | 50 | 60 |
| min | 40 | 45 | 49 | 58.8 |
| r — min | 1.5 | 2 | 2 | 2 |
Materials
- Material, property class and finish specified per RFQ — structural deliveries typically pair a 10.9-class HV bolt with matching EN 14399 nut and washer sets; confirm 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 (EN 14399-4 Hex Bolts with Large Head (System HV)) 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 1,000–10,000 pieces depending on size. Stock items run 3–7 days. High-strength and custom parts run 15–25 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
EN 14399-4 (HV) or HR — and why does the head matter on a structural joint?
The head matters because a structural bolt is a calibrated spring, not just a pin. HV assemblies are tightened to high preload, and the large head spreads that preload over more bearing area, resists head sinking into the washer, and gives the impact wrench a stable platform — which is why EN 14399-4 sizes the head above the general-purpose ISO series at the same thread (across-flats 22 at M12 versus 18 for ISO 4014, per the collected tables). HR (EN 14399-3) is the parallel heavy-hex system with different fit and acceptance rules; HV is the more common European spec where the DAST-directive tightening procedures apply. Order the assembly, not just the bolt: HV preload depends on the nut, the washers (a fitted washer under the head where the source prints the DAST note) and lubrication, so name the assembly class and any project acceptance tests (K-class testing, CE documentation) at RFQ.
What is the MOQ and lead time for this bolt type?
The minimum order quantity is 1,000–10,000 pieces depending on size. Stock items ship in 3–7 days; high-strength and custom parts in 15–25 days. Common sizes in this bolt type are widely stocked; confirm the exact schedule against quantity and size mix at quotation.
Related knowledge
- What Bolt Property Classes 8.8, 10.9 and 12.9 Encode — and When High Strength Stops Being the Right Choice
- Bolt Grade Selection: ISO 898-1 8.8/10.9/12.9 vs ASTM A307 and A325
- 8.8 vs 10.9 vs 12.9 Bolts: Strength, Hardness and Cost — What the Evidence Settles
- Calculating Bolt Preload and Clamp Force: Torque, Friction and Tightening Method
- How to Determine Tightening Torque and Choose a Tightening Method for a Bolted Joint
- Fastener Failure Modes: Which Fatigue, Creep and SCC Controls the Evidence Supports
- Hydrogen Embrittlement in High-Strength Bolts: Which Grades Need Controls, Which Coatings and Baking Schedules Are Acceptable, and What to Require Before the RFQ
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