Nord-Lock® Wedge Lock Washers
Genuine Nord-Lock® wedge-locking washer pairs, supplied by an authorised distributor, that lock bolted joints against vibration with tension rather than friction.
Innovation Fasteners is an authorised Nord-Lock® distributor. Wedge lock washers are supplied as a pre-assembled pair with interlocking cams on the inside faces and radial teeth on the outside. Because the cam rise is greater than the thread pitch, any attempt by the bolt to rotate loose forces the pair apart and increases the clamp load instead of releasing it. The standard series covers M3 to M130 (#5 to 3 in.); the large-OD sp series, M3.5 to M36, has the same bore with a wider bearing face for slotted or oversized holes and soft flange materials. Steel, 316L, 254 SMO, Alloy C-276 and Alloy 718 versions run from −160 °C to 700 °C depending on material.
2 versions, one locking principle.
Specifications & technical data.
As an authorised Nord-Lock® distributor we stock the standard and large-OD (sp) series and supply them with the studs and bolts we make, so the washer, the bolt grade and the certificate arrive together. The tables below give Nord-Lock's published dimensions and the material, hardness and temperature data you need to pick the right pair for the bolt grade. Send us the bolt size and hole detail and we match the series.
| Series | Bolt size (metric / UNC) | d — inside dia. (mm) | D — outside dia. (mm) | T — pair thickness (mm) | d (in) | D (in) | T (in) |
|---|---|---|---|---|---|---|---|
| NL3 | M3 / #5 | 3.4 | 7.0 | 1.8 | 0.134 | 0.276 | 0.071 |
| NL3,5 | M3.5 / #6 | 3.9 | 7.6 | 1.8 | 0.154 | 0.299 | 0.071 |
| NL4 | M4 / #8 | 4.4 | 7.6 | 1.8 | 0.173 | 0.299 | 0.071 |
| NL5 | M5 / #10 | 5.4 | 9.0 | 1.8 | 0.213 | 0.354 | 0.071 |
| NL6 | M6 | 6.5 | 10.8 | 1.8 | 0.256 | 0.425 | 0.071 |
| NL1/4" | 1/4" | 7.2 | 11.5 | 2.3 | 0.283 | 0.453 | 0.091 |
| NL8 | M8 / 5/16" | 8.7 | 13.5 | 2.5 | 0.343 | 0.531 | 0.098 |
| NL3/8" | 3/8" | 10.3 | 16.6 | 2.5 | 0.406 | 0.654 | 0.098 |
| NL10 | M10 | 10.7 | 16.6 | 2.5 | 0.421 | 0.654 | 0.098 |
| NL11 | M11 / 7/16" | 11.4 | 18.5 | 2.5 | 0.449 | 0.728 | 0.098 |
| NL12 | M12 | 13.0 | 19.5 | 2.5 | 0.512 | 0.768 | 0.098 |
| NL1/2" | 1/2" | 13.5 | 19.5 | 2.5 | 0.531 | 0.768 | 0.098 |
| NL14 | M14 / 9/16" | 15.2 | 23.0 | 3.4 | 0.598 | 0.906 | 0.134 |
| NL16 | M16 / 5/8" | 17.0 | 25.4 | 3.4 | 0.669 | 1.000 | 0.134 |
| NL18 | M18 | 19.5 | 29.0 | 3.4 | 0.768 | 1.142 | 0.134 |
| NL3/4" | 3/4" | 20.0 | 30.7 | 3.4 | 0.787 | 1.209 | 0.134 |
| NL20 | M20 | 21.4 | 30.7 | 3.4 | 0.843 | 1.209 | 0.134 |
| NL22 | M22 / 7/8" | 23.4 | 34.5 | 3.4 | 0.921 | 1.358 | 0.134 |
| NL24 | M24 | 25.3 | 39.0 | 3.4 | 0.996 | 1.535 | 0.134 |
| NL1" | 1" | 27.9 | 39.0 | 3.4 | 1.098 | 1.535 | 0.134 |
| NL27 | M27 | 28.4 | 42.0 | 5.8 | 1.118 | 1.654 | 0.228 |
| NL30 | M30 / 1 1/8" | 31.4 | 47.0 | 5.8 | 1.236 | 1.850 | 0.228 |
| NL33 | M33 / 1 1/4" | 34.4 | 48.5 | 5.8 | 1.354 | 1.909 | 0.228 |
| NL36 | M36 / 1 3/8" | 37.4 | 55.0 | 5.8 | 1.472 | 2.165 | 0.228 |
| NL39 | M39 / 1 1/2" | 40.4 | 58.5 | 5.8 | 1.591 | 2.303 | 0.228 |
| NL42 | M42 | 43.2 | 63.0 | 5.8 | 1.701 | 2.480 | 0.228 |
| NL45 | M45 / 1 3/4" | 46.2 | 70.0 | 7.0 | 1.819 | 2.756 | 0.276 |
| NL48 | M48 | 49.6 | 75.0 | 7.0 | 1.953 | 2.953 | 0.276 |
| NL52 | M52 / 2" | 53.6 | 80.0 | 7.0 | 2.110 | 3.150 | 0.276 |
| NL56 | M56 / 2 1/4" | 59.1 | 85.0 | 7.0 | 2.327 | 3.346 | 0.276 |
| NL60 | M60 | 63.1 | 90.0 | 7.0 | 2.484 | 3.543 | 0.276 |
| NL64 | M64 / 2 1/2" | 67.1 | 95.0 | 7.0 | 2.642 | 3.740 | 0.276 |
| NL68 | M68 | 71.1 | 100.0 | 9.5 | 2.799 | 3.937 | 0.374 |
| NL72 | M72 | 75.1 | 105.0 | 9.5 | 2.957 | 4.134 | 0.374 |
| NL76 | M76 / 3" | 79.1 | 110.0 | 9.5 | 3.114 | 4.331 | 0.374 |
| NL80 | M80 | 83.1 | 115.0 | 9.5 | 3.272 | 4.528 | 0.374 |
| NL85 | M85 | 88.1 | 120.0 | 9.5 | 3.469 | 4.724 | 0.374 |
| NL90 | M90 | 92.4 | 130.0 | 9.5 | 3.638 | 5.118 | 0.374 |
| NL95 | M95 | 97.4 | 135.0 | 9.5 | 3.835 | 5.315 | 0.374 |
| NL100 | M100 | 103.4 | 145.0 | 9.5 | 4.071 | 5.709 | 0.374 |
| NL105 | M105 | 108.4 | 150.0 | 9.5 | 4.268 | 5.906 | 0.374 |
| NL110 | M110 | 113.4 | 155.0 | 9.5 | 4.465 | 6.102 | 0.374 |
| NL115 | M115 | 118.4 | 165.0 | 9.5 | 4.661 | 6.496 | 0.374 |
| NL120 | M120 | 123.4 | 170.0 | 9.5 | 4.858 | 6.693 | 0.374 |
| NL125 | M125 | 128.4 | 173.0 | 9.5 | 5.055 | 6.811 | 0.374 |
| NL130 | M130 | 133.4 | 178.0 | 9.5 | 5.252 | 7.008 | 0.374 |
Dimensions per the Nord-Lock® original washer dimension guide (steel series). d is the inside diameter, D the outside diameter and T the thickness of the assembled pair. Metric M3 – M130 and UNC #5 – 3 in.; equivalent wedge-locking washers from other makers are dimensioned the same way. Confirm the series against your bolt and hole with our estimating team.
| Series | Bolt size (metric / UNC) | d — inside dia. (mm) | D — outside dia. (mm) | T — pair thickness (mm) | d (in) | D (in) | T (in) |
|---|---|---|---|---|---|---|---|
| NL3,5sp | M3.5 / #6 | 3.9 | 9.0 | 1.8 | 0.154 | 0.354 | 0.071 |
| NL4sp | M4 / #8 | 4.4 | 9.0 | 1.8 | 0.173 | 0.354 | 0.071 |
| NL5sp | M5 / #10 | 5.4 | 10.8 | 1.8 | 0.213 | 0.425 | 0.071 |
| NL6sp | M6 | 6.5 | 13.5 | 2.5 | 0.256 | 0.531 | 0.098 |
| NL1/4"sp | 1/4" | 7.2 | 13.5 | 2.5 | 0.283 | 0.531 | 0.098 |
| NL8sp | M8 / 5/16" | 8.7 | 16.6 | 2.5 | 0.343 | 0.654 | 0.098 |
| NL3/8"sp | 3/8" | 10.3 | 21.0 | 2.5 | 0.406 | 0.827 | 0.098 |
| NL10sp | M10 | 10.7 | 21.0 | 2.5 | 0.421 | 0.827 | 0.098 |
| NL12sp | M12 | 13.0 | 25.4 | 3.4 | 0.512 | 1.000 | 0.134 |
| NL1/2"sp | 1/2" | 13.5 | 25.4 | 3.4 | 0.531 | 1.000 | 0.134 |
| NL14sp | M14 / 9/16" | 15.2 | 30.7 | 3.4 | 0.598 | 1.209 | 0.134 |
| NL16sp | M16 / 5/8" | 17.0 | 30.7 | 3.4 | 0.669 | 1.209 | 0.134 |
| NL18sp | M18 | 19.5 | 34.5 | 3.4 | 0.768 | 1.358 | 0.134 |
| NL3/4"sp | 3/4" | 20.0 | 39.0 | 3.4 | 0.787 | 1.535 | 0.134 |
| NL20sp | M20 | 21.4 | 39.0 | 3.4 | 0.843 | 1.535 | 0.134 |
| NL22sp | M22 / 7/8" | 23.4 | 42.0 | 4.6 | 0.921 | 1.654 | 0.181 |
| NL24sp | M24 | 25.3 | 48.5 | 4.6 | 0.996 | 1.909 | 0.181 |
| NL1"sp | 1" | 27.9 | 48.5 | 4.6 | 1.098 | 1.909 | 0.181 |
| NL27sp | M27 | 28.4 | 48.5 | 5.8 | 1.118 | 1.909 | 0.228 |
| NL30sp | M30 / 1 1/8" | 31.4 | 55.0 | 5.8 | 1.236 | 2.165 | 0.228 |
| NL33sp | M33 / 1 1/4" | 34.4 | 58.5 | 5.8 | 1.354 | 2.303 | 0.228 |
| NL36sp | M36 / 1 3/8" | 37.4 | 63.0 | 5.8 | 1.472 | 2.480 | 0.228 |
Enlarged outside diameter series for slotted holes, oversized holes and soft or painted flange faces. Same inside diameter as the standard series; the outer face is wider and, in most sizes, the pair is thicker. Available M3.5 – M36 and #6 – 1 3/8 in. in steel, to M30 / 1 1/8 in. in stainless.
| Material | Condition | Hardness, min | Service temperature | Corrosion resistance | Suits bolts up to |
|---|---|---|---|---|---|
| Alloy steel (EN 1.7182) | Through hardened, zinc-flake coated (Delta Protekt® basecoat, Delta Seal GZ topcoat) | 465 HV1 | −50 °C to 200 °C (−58 °F to 392 °F) | 1,000 h salt spray min | Class 12.9 / ASTM A574 |
| 316L stainless (EN 1.4404) | Surface hardened, uncoated | 520 HV0.05 | −160 °C to 500 °C (−256 °F to 932 °F) | PREN 27 | A4-80 / A193 B8M Cl.2 |
| 254 SMO® (EN 1.4547) | Surface hardened, uncoated | 600 HV0.05 | −160 °C to 500 °C (−256 °F to 932 °F) | PREN 45 | A193 B8MLCuN |
| Alloy C-276 (EN 2.4819) | Surface hardened, uncoated | 520 HV0.05 | −160 °C to 500 °C (−256 °F to 932 °F) | PREN 68 | Hastelloy C-276 bolting |
| Alloy 718 (EN 2.4668) | Surface hardened, uncoated | 620 HV0.05 | −160 °C to 700 °C (−256 °F to 1292 °F) | PREN 29 | Inconel 718 bolting |
Per the Nord-Lock® original washer product information. Hardness is the washer face hardness; the washer must be harder than the mating nut face and joint surface to bite. Corrosion figures are the maker's salt-spray hours (ISO 9227) or pitting resistance number.
Standards.
How wedge lock washers work
A wedge lock washer is a pair of identical washers assembled cam face to cam face. Each cam face carries a series of ramps whose rise is greater than the pitch of the bolt thread, and the outer faces carry radial teeth that grip the nut and the joint surface. Once the bolt is tightened the teeth lock each washer to its mating surface, so the only movement left is between the two cam faces. If vibration tries to turn the nut loose, the cams ride up on each other and the joint gets tighter rather than looser. The pair locks with clamp load rather than friction, which is why it holds where split-ring and tooth washers fail the Junker test.
Standard OD or large OD?
- Standard OD: the normal series, matching the bearing area of a hex nut or cap screw head on a standard clearance hole.
- Large OD: a wider outer diameter for slotted holes, oversized or elongated holes, and soft or painted flange materials where the teeth need more surface to bite into.
- Both series lock the same way and are supplied as glued pairs so the cams cannot be assembled the wrong way round.
Materials and finishes
- Alloy steel, through hardened to 465 HV1 with a zinc-flake coating: 1,000 h salt spray, −50 °C to 200 °C, for bolts to class 12.9
- 316L stainless, surface hardened to 520 HV0.05: −160 °C to 500 °C, PREN 27, for A4-80 and A193 B8M bolting
- 254 SMO super austenitic (PREN 45) and Alloy C-276 (PREN 68) for seawater, sour and chemical service to 500 °C
- Alloy 718, surface hardened to 620 HV0.05, for high-temperature bolting to 700 °C
- The washer must be harder than the nut face and the joint surface; on soft or painted flanges use the sp series, which spreads the bite over a larger face
Tips for purchasing
- Buy genuine: Nord-Lock® washers carry the maker's mark on the outer face and come with a certificate of conformity from us as an authorised distributor.
- Order by bolt size and series; the pair is sized to the bolt, not the hole, except where the large-OD series is chosen for a slotted hole.
- One pair under the nut is standard; add a pair under the head as well when the bolt head turns during tightening.
- They are reusable, but inspect the cam faces and teeth after each disassembly.
- Torque to the bolt manufacturer's values; wedge lock washers do not change the torque-tension relationship of a lubricated joint.
Materials.
Representative capabilities — every item is manufactured or certified to your specification. Confirm requirements with our estimating team.
