Wedge-Locking Washers (Nord-Lock Type Pair)
Tension-based wedge-locking washer pairs in the Nord-Lock pattern — cams mate inside the pair, radial teeth grip the nut and joint face. Standard range M3–M130; locking holds under extreme vibration and dynamic loads and is not degraded by temperature, unlike friction-based nylon inserts limited to −50 °C to +120 °C under ISO 2320.
Last updated: 2026-11
Specifications
A wedge-locking washer pair defeats back-off by geometry, not by friction. Each pair is two identical washers: chamfered cam faces mate on the inside, and radial serrations on the outer faces bite into the underside of the nut and the top of the joint. Because the cam angle is greater than the thread pitch, any rotation of the nut trying to loosen the joint drives the cams apart instead — the clamp load actually rises rather than the nut backing off. That is why this pattern is the default where joints see extreme vibration and dynamic loads: it was qualified in the Junker vibration test, considered the most severe vibration test for bolted connections, where friction-based locks walk loose. Practical consequences buyers care about: the joint can be lubricated with predictable clamp load, the washers are reusable without affecting the bolts or nuts, and locking performance does not fade with temperature the way a nylon insert does. Standard range covers M3–M130, and the washers meet ELV and RoHS directives.
| Type | Pair of washers — cams on one side, radial teeth on the other; the pair locks through tension instead of friction |
|---|---|
| Locking principle | Cam angle greater than the thread pitch — rotation that would loosen the fastener wedges the pair apart and blocks it |
| Size range | M3–M130 standard range (nylon insert nuts typically stop at M3–M48) |
| Temperature behavior | Same operating range as regular bolts and nuts — locking function not affected by temperature changes (nylon insert efficiency drops as temperature rises; ISO 2320 limits it to −50 °C to +120 °C) |
| Reusability | Reusable — does not affect the reusability of the bolts or nuts (nylon inserts are not recommended for reuse) |
| Clamp load control | Clamp load can be predicted and the joint lubricated, further minimizing clamp-load deviation and torsion stress |
| Vibration qualification | Tested in the Junker vibration test — considered the most severe vibration test for bolted connections |
| Compliance | Recyclable; meets ELV and RoHS directives |
| Typical applications | Joints exposed to extreme vibration and dynamic loads — transmission fittings, cranes, steel construction (HV/HR sets) |
Materials
- Steel
- Stainless steel
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 (Wedge-Locking Washers (Nord-Lock Type Pair)) 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
Wedge-locking washers vs nylon insert lock nuts — when does the washer pair win?
Wherever vibration, temperature or maintenance cycle count rules out friction locking. A nylon insert locks by friction against the bolt thread; its efficiency varies with insert quality and falls as temperature rises, ISO 2320 bounds it at −50 °C to +120 °C, and the insert is not recommended for reuse. The wedge pair locks by geometry: cams greater in angle than the thread pitch convert loosening rotation into a clamping wedge, so locking holds at the bolt's own temperature range, survives disassembly and reuse, and keeps clamp load predictable even with lubrication. For a static, low-load joint the nylon insert remains the cheaper option — choose the pair when the joint shakes, heats, or gets serviced.
Can a single wedge-locking washer be used, or is the pair required?
The pair is the functional unit. One washer carries the cam face and the other carries the mating geometry, so the wedge action only exists when the two are stacked with cams facing each other — the outer serrated faces then grip the nut and the joint surface. A single washer has no mating counterpart and provides no wedge locking; treating it as a drop-in for an ordinary flat washer is an assembly error, not a cost saving.
What is the MOQ and lead time for this washer 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 washer 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