NSK-LStandard drillings & slotted hole fixings up to 12.9 strength classes
Areas of application
- Highly stressed and high-strength bolted connections in accordance with VDI 2230-1
- Force-fit, static and dynamic transmission of the operating load via the braced components
- Strength classes 8.8 to 12.9 or A70 and A80
- Circular hole and slotted hole connections
- Effective even with limited installation space (See also NSK-B for larger installation spaces)
Special features
- Suitable for high preload forces
- Defined, Defined, constant friction coefficient
- Increases the flexibility of the screw connection
- Special spring characteristics / optimum residual spring behaviour for strength classes 10.9 and 12.9 (Characteristic spring curves shown in M-Design)
- Locking element to prevent loosening & automatic unscrewing
- Complies with standards DIN 267-26, DIN 25201-4, DIN EN 17976
Comparison of possible solutions for highly stressed and high-strength screw connections
| Spring/profile Locking edge ring1 Spring washer2 with washer |
Wedge disc pairs (flat design) |
Wedge disc pairs (conical design) |
Clamping disc (DIN6796) |
NSK-L | |
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| Damage to the counterclaims |
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| Defined / reproducible contact pressure (coefficient of friction) |
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| Improved compliance with short clamping lengths |
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| Compensation of slackening effects3 |
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| Compensation of loosening effects4 |
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| Acquisition costs compared to washer DIN 1255 |
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1
DIN 127, 128, 6905, 7980 etc
2
DIN 137, 6904
3
according to VDI 2230, DIN 267-26
4
in accordance with DIN 65151 / DIN 25201- 4
5
same / higher / high
Technical Information
| Spring steel C60 EN 1.1211 |
Stainless steel A41 EN 1.4401 (in preparation) |
Other materials EN 1.4547, EN 2.4819, EN 2.4668 (on request) | |
|---|---|---|---|
| Hardness / Strength | ≥ 430 HV10 | ≥ 595 N/mm2 | depending on material |
| Coating | Zinc flake coating | - | - |
| Corrosion protection | > 720h in the salt spray test (according to ISO 9227) | PREN 27 (bezogen auf Grundwerkstoff) | depending on material |
| Temperature range | -40°C to 150°C | -40°C to 150°C | depending on material |
| Screw quality | 8.8 - 12.9 | up to and including A4-80 |
depending on material |
| Dimension range | M6 - M20 | M6 - M20 | as required |
1
can also be used for stainless steel A2 screws, e.g. EN 1.4301 or EN 1.4310
Applications
Why do screw connections come loose?
How does an NSK-L work?
Force-locking effect with curved geometry matched to the preload force depending on the strength class.
- Increases the flexibility of a bolted joint
- Prevents slackening effects and supports the locking effect against selfacting loosening
Form locking effect due to the interlocking under the screw head or on the nut.
- Supports the locking effect against selfacting loosening
How are NSK-L tested?
Minimum residual spring force test according to DIN 267-26
Force measurement, if the screw connection is relieved by 20μm (Technical specifications for conical spring steel washers for bolted joints)
Spring characteristic curve, matched to:
- Strength class 10.9 and 12.9 (steel)
- A80 for stainless steel 1.4401
Vibration test according to DIN 65151 & DIN 25201-4 Annex B.
- Application-orientated testing on circular-holes and slotted holes
- Internal testing equipment are verified by external institutes.
Pressure cone test
Deflection tests
The functional properties and tests for slotted hole connections are not defined in standards. The tests, carried out by teckentrup SLI, are used for orientation.
The properties and testing methode for slotted hole connections must be specified by the user.
Spring steel (C60) with zinc flake
| NSK-L | Article No. | DI | DA | S | H | Weight/1.000 St. | Pcs. per unit | 3D Download | Request |
|---|---|---|---|---|---|---|---|---|---|
| NSK-L6 | 070230 | Ø 6.10+0,48 | Ø 14.20-0,43 | 2.40±0.04 | 3.10±0.20 | 2,13 kg | 1.000 | Download | Add to request list |
| NSK-L8 | 070240 | Ø 8.20+0.58 | Ø 18.20-0.52 | 2.40±0.05 | 3.40±0.25 | 3,94 kg | 1.000 | Download | Add to request list |
| NSK-L10 | 070250 | Ø 10.20+0.58 | Ø 22.25-0.52 | 2.80±0.06 | 3.70±0.25 | 6,83 kg | 500 | Download | Add to request list |
| NSK-L12 | 070260 | Ø 12.40+0.58 | Ø 27.25-0.52 | 2.80±0.06 | 4.30±0.25 | 10,11 kg | 500 | Download | Add to request list |
| NSK-L14 | 070270 | Ø 14.40+0.58 | Ø 30.25-0,52 | 3.50±0.06 | 4.70±0.25 | 15,27 kg | 250 | Download | Add to request list |
| NSK-L16 | 070280 | Ø 16.40+0.58 | Ø 32.50-0.52 | 3.50±0.07 | 4.90±0.30 | 16,80 kg | 250 | Download | Add to request list |
| NSK-L20 | 070300 | Ø 21,00+0,58 | Ø 40,00-0,52 | 4.00±0.07 | 6.00±0.30 | 28,58 kg | 100 | Download | Add to request list |
Technical changes reserved
The securing effect of the NSK-B and NSK-L on slotted holes is verified using a wide range of test methods. The hole clearance in the transverse direction corresponds to normal holes (DIN EN 20273; tolerance class H 13, medium). Furthermore, slotted hole edges are always deburred. For your own applications, it is recommended that you carry out your own tests with specialised personnel.
3D Download
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