DIN 604 Flat Countersunk Nib Bolts
DIN 604 flat countersunk nib bolts, M6–M24 — carriage-bolt family with a countersunk head and two nibs that key into the hole against rotation, with the collected per-size tables: pitch, b ladder, d k, s, k, α and i.
Last updated: 2026-11
Specifications
DIN 604 is the countersunk member of the nib-bolt (Rippen-/Nippelschraube) family: a round head with a flat 90° countersink that sits flush in a counterbored hole, and two parallel nibs under the head that bite into the seating surface to stop the bolt spinning while the nut is torqued. That makes it the one-tool install in the carriage-bolt world — the classic square-neck carriage bolt needs the square to jam in a square hole, while a nib bolt works in a round hole with a simple counterbore, so it is the retrofit-friendly choice on timber, sheet-metal and conveyor work where drilling a square hole is not practical. The collected tables run M6 to M24: pitch, the three-regime thread-length ladder b, head diameter d k (max/min), nib width s, head height k, the countersink angle α and nib height i. Mind the angle note in the table — the source prints 90°–95° through M16 and 60°–65° at M20/M24, so the counterbore angle follows the size. Heads are countersunk: the flush seat is the feature, and the collected tables carry head geometry only, so finishes and property classes stay per RFQ.
| Standard | DIN 604 — flat countersunk nib bolts (countersunk head, two nibs against rotation) |
|---|---|
| Series | M6 – M24 (two source column groups: M6/M8/M10/M12 and M16/M20/M24) |
| Tabulated geometry | Per size: pitch P, b ladder (L≤125 / 125<L≤200 / L>200, "/" at M6 L>200), d k (max/min), nib width s (max/min), head height k (max), countersink angle α (min/max), nib height i (min) |
| Head seat | Countersunk head, flush in a counterbore; α = 90°–95° M6–M16 and 60°–65° M20/M24 as printed — see table footnote |
| Property classes / finishes | Not tabulated by the collected specification — per RFQ |
| Attribute | M6 | M8 | M10 | M12 |
|---|---|---|---|---|
| P — Pitch | 1 | 1.25 | 1.5 | 1.75 |
| Length of Thread b — L≤125 | 18 | 22 | 26 | 30 |
| 125＜L≤200 | 24 | 28 | 32 | 36 |
| L＞200 | / | 41 | 45 | 49 |
| d k — max | 12.55 | 16.55 | 19.65 | 24.65 |
| min | 11.45 | 15.45 | 18.35 | 23.35 |
| s — max | 2.5 | 3 | 3.2 | 3.6 |
| min | 2.1 | 2.6 | 2.72 | 3.12 |
| k — max | 4 | 5 | 5.5 | 7 |
| α — min | 90° | 90° | 90° | 90° |
| max | 95° | 95° | 95° | 95° |
| i — min | 2.8 | 3.5 | 4.2 | 5.7 |
- Row 4 (L＞200): The source prints '/' at M6 for the L>200 regime — no b 3 value tabulated for the smallest size.
| Attribute | M16 | M20 | M24 |
|---|---|---|---|
| P — Pitch | 2 | 2.5 | 3 |
| Length of Thread b — L≤125 | 38 | 46 | 54 |
| 125＜L≤200 | 44 | 52 | 60 |
| L＞200 | 57 | 65 | 73 |
| d k — max | 32.8 | 32.8 | 38.8 |
| min | 31.2 | 31.2 | 37.2 |
| s — max | 4.2 | 5.4 | 6.6 |
| min | 3.72 | 4.92 | 6.02 |
| k — max | 9 | 11.5 | 13 |
| α — min | 90° | 60° | 60° |
| max | 95° | 65° | 65° |
| i — min | 7.5 | 5.7 | 6.7 |
- Row 5 (d k — max): The source prints identical d k values (32.8/31.2) for M16 and M20 — reproduced verbatim as printed.
- Row 10 (α — min): The source changes the countersink angle above M16: 90°–95° through M16, 60°–65° at M20/M24.
Materials
- Material and finish specified per RFQ — state the seating material (timber, sheet, plastics) so the nib and countersink geometry is confirmed against the joint 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 604 Flat Countersunk Nib Bolts) 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
DIN 604 (countersunk nib) or DIN 603 (square-neck carriage bolt)?
Both are anti-rotation bolts that clamp with a nut, and the choice is really about the hole. The DIN 603 carriage bolt's square neck needs a square-punched or square-drilled hole in the outer ply — fine in timber and standard on farm and trailer work. The DIN 604 nib bolt keys on two small nibs, so a round counterbored hole is enough: on sheet-metal chutes, conveyor pans and retrofit jobs where re-drilling square holes is out of the question, DIN 604 installs with ordinary tooling. The trade-offs: the countersunk head sits flush (a clearance benefit and a snag-free surface) but offers less bearing area than the domed carriage head, and the nibs mark soft seating faces slightly. Thread length follows the three-regime b ladder in the collected tables — check your total grip against it before ordering, and note the countersink angle changes to 60°–65° from M20 (as the source prints) so the counterbore tooling matches.
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