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FULLERKREG DIN 7967 PAL nuts in spring steel 65Mn with zinc plating (Cr3, blue/white) are the standard industrial-grade choice for cost-effective all-metal self-locking counter nut applications. The nut body is radially slotted through, and the two halves are offset during manufacture so that when tightened onto a bolt, the spring tension of the high-carbon spring steel grips the thread flanks and actively resists loosening under vibration and dynamic loads. The 65Mn spring steel base delivers superior spring-back force and locking torque retention compared to standard carbon steel, while the Cr3 zinc plating provides reliable corrosion protection for general industrial environments. This is the most widely stocked and cost-competitive variant of DIN 7967 PAL nuts.
| Standard | DIN 7967 |
| Common Name | PAL Nut · Self-Locking Counter Nut · Spring Nut |
| Material | Spring Steel 65Mn (High-Carbon Manganese Spring Steel) |
| Surface Treatment | Zinc Plated — Cr3 Trivalent Chromate (Blue/White Passivation) |
| RoHS Compliance | Yes — Cr3 (trivalent chromium), hexavalent chromium-free |
| Locking Mechanism | All-Metal Spring Action (radial slot + thread offset between two halves) |
| Thread | Metric Coarse Thread (ISO 68-1) |
| Size Range | M4 – M52 (Series 1 standard range; Series 2 & 3 for fine pitch) |
| Drive Type | Hex (Wrench / Spanner) |
| Nut Profile | Thin / Low Profile (Counter Nut) |
| Hardness | 350–425 HV (per DIN 7967 / spring steel grade) |
| Reusability | Good — all-metal, no nylon insert to degrade |
| Max Operating Temp. | Up to +300 °C (no nylon insert limitation; zinc coating limit ~200 °C) |
| Salt Spray Resistance | ≥96 hours (Cr3 zinc plating, per ISO 9227) |
| Property | Spring Steel 65Mn (This Product) | Standard Carbon Steel |
|---|---|---|
| Carbon Content | 0.62–0.70% C | ~0.15–0.45% C |
| Manganese Content | 0.90–1.20% Mn | 0.30–0.80% Mn |
| Hardness | 350–425 HV | ~120–200 HV |
| Spring-Back Force | High — superior locking torque retention | Low — may relax under load |
| Locking Torque Retention | Excellent (per DIN 7967 prevailing torque spec) | Poor |
| Cost | Economical — most cost-effective DIN 7967 variant | Low |
| Feature | DIN 7967 PAL Nut (Spring Steel Zn) | Nylon Insert Lock Nut (DIN 985) | Thin Jam Nut (DIN 439) |
|---|---|---|---|
| Locking Method | All-metal spring tension (slotted body) | Non-metallic nylon insert | Friction only (no locking) |
| Max Temperature | Up to +300 °C (steel); ~200 °C (Zn coating) | Max ~120 °C (nylon limit) | Material-limited only |
| Profile | Thin / low profile | Standard height | Thin / low profile |
| Reusability | Good (metal spring retains tension) | Limited (nylon degrades) | Unlimited (no locking element) |
| Vibration Resistance | High (active spring locking) | High (nylon grip) | Low (friction only) |
| Cost | Most economical locking nut option | Low–moderate | Low |
| RoHS | Yes (Cr3 trivalent zinc) | Yes | Depends on finish |
All dimensions in mm per DIN 7967. Tolerances per ISO 4759-1. Series 1 = metric coarse thread (standard). Series 2 & 3 = fine pitch threads (available on request). Note: zinc plating adds approximately 5–15 μm per side; thread fit verified per standard.
| Thread d |
Pitch p (mm) |
Wrench Size s (mm) |
e min (mm) |
Nut Height m (mm) |
v (mm) | Unit Weight (g/pc) |
|---|---|---|---|---|---|---|
| M4 | 0.70 | 7 | 7.66 | 1.8 | 0.3 | ~0.17 |
| M5 | 0.80 | 8 | 8.79 | 2.0 | 0.4 | ~0.28 |
| M6 | 1.00 | 10 | 11.05 | 2.5 | 0.4 | ~0.40 |
| M8 | 1.25 | 13 | 14.38 | 3.0 | 0.5 | ~0.90 |
| M10 | 1.50 | 17 | 18.90 | 3.5 | 0.5 | ~1.40 |
| M12 | 1.75 | 19 | 21.10 | 4.0 | 0.6 | ~1.90 |
| M14 | 2.00 | 22 | 24.49 | 4.0 | 0.7 | ~2.50 |
| M16 | 2.00 | 24 | 26.75 | 5.0 | 0.7 | ~3.40 |
| M18 | 2.50 | 27 | 29.56 | 5.0 | 0.7 | ~4.10 |
| M20 | 2.50 | 30 | 32.95 | 5.0 | 0.8 | ~5.80 |
| M22 | 2.50 | 32 | 35.03 | 6.0 | 0.9 | ~8.40 |
| M24 | 3.00 | 36 | 39.55 | 6.0 | 0.9 | ~9.50 |
| M27 | 3.00 | 41 | 45.20 | 7.0 | 1.0 | ~13.00 |
| M30 | 3.50 | 46 | 50.85 | 7.0 | 1.1 | ~17.50 |
| M33 | 3.50 | 50 | 55.37 | 8.0 | 1.2 | ~22.00 |
| M36 | 4.00 | 55 | 60.79 | 9.0 | 1.3 | ~29.00 |
| M39 | 4.00 | 60 | 66.44 | 9.0 | 1.3 | ~32.00 |
| M42 | 4.50 | 65 | 71.30 | 11.0 | 1.4 | ~45.00 |
| M45 | 4.50 | 70 | 76.95 | 12.0 | 1.5 | ~54.00 |
| M48 | 5.00 | 75 | 82.60 | 14.0 | 1.6 | ~75.00 |
| M52 | 5.00 | 80 | 88.25 | 16.0 | 1.7 | ~95.00 |
* Unit weights (g/pc) are derived from DIN 7967 standard weight data (kg/1000 pcs) and are approximate reference values based on spring steel 65Mn density (7.85 g/cm³). Actual weight may vary ±5% due to manufacturing tolerances. Contact FULLERKREG for certified weight data if required. v = slot offset dimension.
| Application Scenario | Recommended Size | Notes |
|---|---|---|
| General industrial machinery | M4 – M52 | Most cost-effective all-metal locking nut for standard environments |
| Automotive & transportation | M6 – M24 | High spring-back force; resists vibration loosening without adhesives |
| Agricultural & construction equipment | M10 – M36 | Zinc Cr3 provides adequate corrosion protection for outdoor use |
| Counter / jam nut with active locking | M4 – M52 | Low profile ideal for locking against primary nut |
| High-temperature assemblies (>120 °C, <200 °C) | M6 – M36 | All-metal; no nylon insert limit; zinc coating stable to ~200 °C |
| Electrical & panel assemblies | M4 – M16 | RoHS-compliant Cr3 zinc; safe for electronics environments |
| Fine-pitch thread applications | M8×1 – M39×3 (Series 2/3) | Contact FULLERKREG for fine-pitch series availability |
These nuts are manufactured to DIN 7967 — Self-locking counter nuts, prevailing torque type, all-metal. The standard defines three series: Series 1 (metric coarse thread, 9 locking teeth), Series 2 and Series 3 (metric fine pitch threads, 9 locking teeth). The locking action is achieved by a radial slot through the nut body combined with a deliberate thread offset between the two halves, creating a spring-like clamping force on the bolt thread flanks. The 65Mn spring steel base material is specifically chosen for its high hardness (350–425 HV) and excellent elastic recovery, ensuring consistent prevailing torque performance across multiple installation cycles.
Related standards: ISO 7042 (all-metal prevailing torque hex nuts) · DIN 985 (nylon insert lock nut) · DIN 439 (thin hex nut / jam nut) · ISO 2320 (prevailing torque requirements) · ISO 4759-1 (dimensional tolerances) · ISO 9227 (salt spray corrosion test)
DIN 7967 PAL Self-Locking Counter Nuts — Spring Steel 65Mn, Zinc Plated Cr3
| [Photo 1] | [Photo 2] | [Photo 3] | [Photo 4] |
🏭 Direct Manufacturer — No middlemen. Factory-direct pricing on all standard and custom fasteners.
📐 DIN 7967 Precision — Every batch produced and inspected to full dimensional and prevailing torque requirements.
🔩 Full Material Traceability — 65Mn spring steel mill certificates and RoHS Cr3 zinc compliance documentation available on request.
📦 Flexible MOQ & Bulk Packaging — From sample packs to pallet quantities; custom labeling and kitting available.
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