"OLTSECURINGSYSTEM

This unique bolt securing system uses tension

to make the bolt self-locking
 The small details provide the best
locking effect
Nord-Lock® is a pair of washers with a wedge-locking action meeting DIN 25 201
which is a unique method using tension instead of friction. The rise of the
cams between the two Nord-Lock® washers is greater than the pitch of the
bolt. In addition, there are radial teeth on the opposite side. When the bolt
and/or nut is tightened, the teeth grip and seat the mating surfaces.
The Nord-Lock® washer is locked in place, allowing movement only across
Nord-Lock® has cams on one side
the face of the cams. The tension created makes the bolt/nut self-locking so
with a greater rise than the pitch
of the bolt. In addition, Nord-Lock® it cannot move.
has radial teeth on the opposite
side. The washers are installed in
pairs, cam face to cam face.

AB

Security test Temperatures

A quick test of the locking function is to The Nord-Lock® washers have the same
tighten and loosen the fastener. When temperature characteristics as the bolts
un-tightening, the cam overriding ”click” and nuts of corresponding material
effect must occur. The locking effect quality.
can never be judged by measuring Steel starts to degrade at temperatures
the break-away-torque since the over 200°C and stainless steel starts to
Where are they used? friction is lower between the cam faces. degrade at temperatures over 500°C
• Construction equipment The break-away torque is less than the as do the nuts/bolts.
• Automotive industry tightening torque.
• Agriculture equipment
• Off-road
• Manufacturing equipment
• Mining The key is the difference in angles. Here
• Oil industry you see what happens when a nut
• Railroad equipment
• Trucking industry attempts to loosen. The pair of washers
• Utilities expand more than the corresponding
• Power plants
pitch of the thread. Nord-Lock® washers
• Process industries
positively lock the fastener in a joint
which is subjected to any vibration or
2 dynamic loads.
Nord-Lock® maintains the bolt tension
with the highest possible safety
Junker vibration test
One method for testing the security of a of preload which is caused mainly by
bolted joint is the Junker-vibration test. settlement in the thread.
The preload (bolt tension) is measured Even after moderate tightening the bolt
by a load cell and vibrating motions are is safely locked when using Nord-Lock®.
generated radially through the bolt. Recommended torque figures (see
Nord-Lock® together with a standard nut page 7) are based on tests in our own
Amplitude: +0,3 mm/+0,5 mm
achieves a locking that is superior to other laboratory with calibrated torque
Frequency: 40 Hz
locking hardware e.g. nylon-inserted nuts. transmitters and load cells.
Clamp length: 25 mm - 50 mm
Bolts that are locked by friction in
Hardness
the thread lose most of their preload
of mating
through vibrations while those locked material: HRA 63–65
with Nord-Lock® present a minor loss

Junker vibration test diagrams

Vibration test Untightening

bolt with clamp length 25 mm
Clamp load [kN]

Regular nut M8 on bolt with Nord-Lock®

at 70% of yield point
Regular nut M8 on bolt, clamp length
50 mm
Nylon-inserted nut
Split ring
Regular nut M8 on bolt
Regular nut M8 on bolt with Nord-Lock®
at 25% of yield point

The Nord-Lock® washers have

been used in various industries for
many years with excellent results.
Time [seconds]

Vibration test with tab washer and locking wire

Vibration test
Clamp load [kN]

Locking wire
Locking wire

Tab washer

Tab washer

Time [seconds] 3
 Long holes and softer materials
In order to cover as much surface as Normally a standard bolt and standard
possible it is recommended to use Nord-Lock® washer will work, however,
flanged nuts and bolts in combination it is recommended to make a tightening
with Nord-Lock® washers with a large test to determine the depths of the
outer diameter. impressions around the hole area.

Vibration test with long holes

Vibration test
Clamp load [kN]
long holes

Flange nut with Nord-Lock® sp (large outer diameter)

Regular nut with Nord-Lock® sp (large outer diameter)
Regular nut with Nord-Lock® standard (standard outer diameter)

Time [seconds]
Examples of Nord-Lock® used in
combination with long holes.
From top picture:
• Flange nut with NL sp (large
outer diameter) Painted surfaces
• Regular nut with NL sp (large
outer diameter) When tightening towards a painted head/nut. In both cases there will be a
• Regular nut with NL standard surface sliding may occur towards the positive locking effect since sliding in off-
(regular outer diameter)
paint if there is a thick and soft layer of torque direction will be on the cam faces
paint. If the paint is hard, sliding will occur of the washers where the friction is lower
between the upper washer and bolt than on the serrated surfaces.

Vibration test with lubricated bolt on painted surface

Vibration test
Untightening
Nord-Lock® on painted surface (t = 80 μm)
Clamp load [kN]

Painted surface after use of Nord-

Lock® with large outer diameter.

Regular nut M8 on bolt with Nord-Lock®

lubricated, reused 9 times
Regular nut M8 on bolt with Nord-Lock®
first application

Painted surface after use of Nord-

Lock® with standard diameter.

4 Time [seconds]
Corrosion resistance Available in
Corrosion test according to SS-ISO 9227 • Yellow zinc chromate (standard)
• Dacromet® coated
• Stainless steel SS 2343 (AISI 316)
• Large and small outside diameter
• Pre-assembled
Available in a variety of sizes
Steel: M3–M130, #5–5”
Stainless steel: M3–M80, #5–31/8”
Dimension list
Electro zinc yellow chromate after 144 hours Dacromet® after 400 hours For our current dimension list,
please visit www.nord-lock.com.

Reusability
Since sliding always occurs between In combination with 8.8 bolt/nut Nord-
the Nord-Lock® washers and the head Lock® can be reused up to 5 times if the
of the bolt/nut when tightening, and washers are lubricated before re-assembly.
between the cam faces of the washers On high-grade and stainless steel, bolt/
when untightening, the friction will nut reuse is not recommended.
not increase under the nut/bolt as with
other serrated fasteners.

Laboratory tests
Test report no. 375-130-91 carried you in most cases as far as torque/load
out by the German TÜV confirms that ratios and security tests during severe
after two million cycles the tension vibration in their simulators.
is maintained. An inspection of the Please contact your local Nord-Lock®
washers showed that Nord-Lock® could agent for consultations, you can find
be used safely. them at www.nord-lock.com.
The Nord-Lock® manufacturer will support

Hardness
Materials Range Electro zinc Dacromet Non-coated
ISO2081 (ISO/Rfe/Zn8c2C)
Standard steel NL3–NL42 HRA 75 ±4% HRA 73 ±4%
(through hardened) NL45–NL130 HRA 72 ±4%
Stainless steel NL3 ss–NL80 ss HV0,05 > 520
(A4)

Stainless steel specifications of A4

Norm C<% Si < % Mn < % P<% S<% Cr % Mo % Ni %
SS 2343 0,05 1,00 2,00 0,045 0,030 16,0 – 18,5 2,50 – 3,00 10,5 – 14,0
EN 1.4436 0,07 1,00 2,00 0,045 0,025 16,5 – 18,5 2,50 – 3,00 11,0 – 14,0
AISI 316 0,08 1,00 2,00 0,045 0,025 16,0 – 18,0 2,00 – 3,00 10,0 – 14,0

Nord-Lock washers are made of stainless steel SS 2343.

®

Pre-assembled Torque – Friction – Load

Nord-Lock® washers are available as pre- Of course a bolt will give different
assembled pairs. A standard hot melt tensions due to surface conditions,
glue (NATIONAL 281E) is used between though the applied torque is the same.
the Nord-Lock® washers.

5
 Torque – load diagrams
It has become more and more torque to obtain the desired clamp
important to have good control of load with a minimum of deviation.
the torque-clamp load relationship Due to the fact that the clamp load
when tightening a joint. To optimize of the joint depends on the friction
the design of the joint and utilize between the sliding surfaces, you
as much of the capacity of each will receive different clamp loads
dimension as possible, you need depending on the surface conditions.
to know the required tightening

Untightening Tightening

Load [kN]
Regular nut M8
on steel without
15 washer

10

Regular nut M8
on aluminium
5 without washer

-25 -20 -15 -10 -5 5 10 15 20 25

Torque [Nm]

Above diagram shows the deviation in you are tightening against (aluminium
clamp load when not using any washer. or steel). Because of the higher friction
When applying the same tightening when tightening against aluminium
torque you will receive different clamp the clamp load will be much lower.
load values depending on the material

Untightening Tightening

Regular nut M8
Load [kN]

on steel with
15 Nord-Lock®
washers

10
Regular nut M8 on
aluminium with
Nord-Lock® washers

Torque [Nm]

When using Nord-Lock® washers sliding the head of the bolt, with the same
will always occur between the same surface conditions. You will receive a
surfaces, i.e. between the washer and clamp load with a minimum of deviation.
6
Nord-Lock washer material / type guide

Application Steel Stainless steel (ss) 254 SMO ® INCONEL® / INCONEL® 718
parameter washers washers washers HASTELLOY® C-276 washers washers

Steel type EN 1.7182 or equivalent EN 1.4404 or equivalent EN 1.4547 or equivalent EN 2.4819 or equivalent EN 2.4667 or equivalent

Examples of General steel General stainless General salt water General acidic Applications with high
applications applications steel applications. applications, pumps, environments, process temperatures, gas
Non chlorine / acid chloride applications, and chemical industry, turbines, turbo
environments heat exchangers, nuclear, evaporators, offshore chargers, incinerators
desalination, food downhole tooling
processing & medical
equipment

Available for #5 to 5” (see page 8 for #5 to 3 1/8” (see page #5 to 1 1/2” (see page #5 to 1 1/2” available #5 to 1 1/2” available
bolt sizes dimensions) 10 for dimensions) 11 for dimensions) upon request upon request

Washer types Regular outer diameter Regular outer diameter Regular outer diameter Regular outer diameter Regular outer diameter
(NL3–NL130) (NL3ss–NL80ss) (NL3ss-254–NL39ss-254) (NL3ss-276–NL39ss-276) (NL3ss-718–NL39ss-718)

Enlarged outer diameter Enlarged outer diameter Enlarged outer diameter Enlarged outer diameter Enlarged outer diameter
(NL3.5sp–NL36sp) (NL3.5spss–NL30spss) (NL3.5spss-254– (NL3.5spss-276– (NL3.5spss-718–
NL27spss-254) NL27spss-276) NL27spss-718)

Treatment Through hardened Surface hardened Surface hardened Surface hardened Surface hardened

Surface coating Delta Protekt ® base coat

(KL100) and top coat
(VH302GZ)

Washer hardness* ≥ 465 HV1 ≥ 520HV0.05 ≥ 600HV0.05 ≥ 520HV0.05 ≥ 620HV0.05

Corrosion Minimum 600 hours PREN 27** PREN 45** PREN 68** PREN 29**
resistance in salt spray test
(according to IS09227)

Bolt grades Up to ASTM A574 Up to ASTM F593 Up to ASTM F593 Up to ASTM F593 Up to ASTM F593

Temperature -4F to 392F -256F to 932F -256F to 932F -256F to 932F -256F to 1292F
range***

* In order to assure the unique mechanical locking function of the Nord-Lock washers, the hardness of the mating surfaces
must be lower than the hardness of the Nord-Lock washers (see table above).
** PREN (Pitting Resistance Equivalent Number) = %Cr + 3.3x%Mo + 16x%N. Figures in table valid for base material.
*** Temperature recommendations based on information from the raw material supplier. Locking function not affected within
the specification.

7
NORD-LOCK washer dimensions METRIC - preassembled pairs
STEEL, ZINC FLAKE COATED (DELTA PROTEKT ®) - ELV & RoHS COMPLIANT

Washer Bolt size øi øo Thickness T Min. package Approx. weight

size Metric UNC [mm] [mm] [mm] [pairs] kg / 100 pairs
NL3 M3 #5 3,4 7,0 1,8 200 0,04
NL3,5 M3,5 #6 3,9 7,6 1,8 200 0,03
NL3,5sp M3,5 #6 3,9 9,0 1,8 200 0,06
NL4 M4 #8 4,4 7,6 1,8 200 0,04 Øi
NL4sp M4 #8 4,4 9,0 1,8 200 0,06
NL5 M5 #10 5,4 9,0 1,8 200 0,05
NL5sp M5 #10 5,4 10,8 1,8 200 0,11
NL6 M6 6,5 10,8 1,8 200 0,07
NL6sp M6 6,5 13,5 2,5 200 0,20
NL3 – NL8
NL1/4” 1/4” 7,2 11,5 1,8 200 0,08
NL1/4”sp 1/4” 7,2 13,5 2,5 200 0,18 Ø i ±0,1 mm
NL8 M8 5/16” 8,7 13,5 2,5 200 0,15 NL10 – NL42
NL8sp M8 5/16” 8,7 16,6 2,5 200 0,29 Ø i ±0,2 mm
NL3/8” 3/8” 10,3 16,6 2,5 200 0,23
NL3/8”sp 3/8” 10,3 21,0 2,5 200 0,46 NL45 – NL130
NL10 M10 10,7 16,6 2,5 200 0,23 Ø i +0,5/-0 mm
NL10sp M10 10,7 21,0 2,5 200 0,44
NL11 M11 7/16” 11,4 18,5 2,5 200 0,29
NL12 M12 13,0 19,5 2,5 200 0,29
NL12sp M12 13,0 25,4 3,4 100 0,91
NL1/2” 1/2” 13,5 19,5 2,5 200 0,27
NL1/2”sp 1/2” 13,5 25,4 3,4 100 0,93
NL14 M14 9/16” 15,2 23,0 3,4 100 0,63
Øo
NL14sp M14 9/16” 15,2 30,7 3,4 100 1,46
NL16 M16 5/8” 17,0 25,4 3,4 100 0,69
NL16sp M16 5/8” 17,0 30,7 3,4 100 1,29
NL18 M18 19,5 29,0 3,4 100 0,85
NL18sp M18 19,5 34,5 3,4 100 1,58
NL3 – NL24
NL3/4” 3/4” 20,0 30,7 3,4 100 1,05
NL3/4”sp 3/4” 20,0 39,0 3,4 100 2,20
Øo ± 0,2 mm
NL20 M20 21,4 30,7 3,4 100 0,95 NL27 – NL42
NL20sp M20 21,4 39,0 3,4 100 2,03 Øo ± 0,3 mm
NL22 M22 7/8” 23,4 34,5 3,4 100 1,29
NL22sp M22 7/8” 23,4 42,0 4,6 50 3,31 NL45 – NL130
NL24 M24 25,3 39,0 3,4 100 1,68 Øo +0/-2,0 mm
NL24sp M24 25,3 48,5 4,6 50 4,51
NL1” 1” 27,9 39,0 3,4 100 1,53
NL1”sp 1” 27,9 48,5 4,6 50 4,20
NL27 M27 28,4 42,0 6,6 50 3,29 T
NL27sp M27 28,4 48,5 6,6 25 5,39
NL30 M30 1 1/8” 31,4 47,0 6,6 50 4,20 NL3 – NL24
NL30sp M30 1 1/8” 31,4 58,5 6,6 25 8,96 T ± 0,25 mm
NL33 M33 1 1/4” 34,4 48,5 6,6 25 3,97
NL27 – NL42
NL33sp M33 1 1/4” 34,4 58,5 6,6 25 8,31
T +0/-0,5 mm
NL36 M36 1 3/8” 37,4 55,0 6,6 25 5,59
NL36sp M36 1 3/8” 37,4 63,0 6,6 25 9,15 NL45 – NL130
NL39 M39 1 1/2” 40,4 58,5 6,6 25 6,28 T ± 0,75 mm
NL42 M42 43,2 63,0 6,6 25 7,47
NL45 M45 1 3/4” 46,2 70,0 7,0 25 * 10,20
NL48 M48 49,6 75,0 7,0 25 * 12,00
* NL45–NL130
NL52 M52 2” 53,6 80,0 7,0 25 * 13,00
NL56 M56 2 1/4” 59,1 85,0 7,0 10 * 13,50 upon inquiry
NL60 M60 63,1 90,0 9,5 10 * 15,20
NL64 M64 2 1/2” 67,1 95,0 9,5 10 * 16,70 Materials and dimensions are
NL68 M68 71,1 100,0 9,5 1* 28,19 subject to change without
NL72 M72 75,1 105,0 9,5 1* 30,70 prior notice.
NL76 M76 3” 79,1 110,0 9,5 1* 33,31 Please consult our website
NL80 M80 83,1 115,0 9,5 1* 36,02 for current dimensions:
NL85 M85 88,1 120,0 9,5 1* 37,84 www.nord-lock.com
NL90 M90 92,4 130,0 9,5 1* 47,67
NL95 M95 97,4 135,0 9,5 1* 49,81
NL100 M100 103,4 145,0 9,5 1* 58,91
NL105 M105 108,4 150,0 9,5 1* 61,28
NL110 M110 113,4 155,0 9,5 1* 63,65
NL115 M115 118,4 165,0 9,5 1* 75,28
NL120 M120 123,4 170,0 9,5 1* 77,94
NL125 M125 128,4 173,0 9,5 1* 76,63
NL130 M130 133,4 178,0 9,5 1* 79,17

8
Torque guidelines

NORD-LOCK zinc flake coated (DP = Delta Protekt®) washers

with electro zinc plated bolt 8.8
Oil, GF=0,75 GTP600, GF=0,75 Dry, GF=0,62
μg= 0,10, μw= 0,16 μg= 0,08, μw= 0,15 μg= 0,15, μw= 0,18
Washer Bolt Pitch Torque Clamp load Torque Clamp load Torque Clamp load
size size [mm] [Nm] [kN] [Nm] [kN] [Nm] [kN]

NL3 M3 0,5 1,3 2,4 1,2 2,4 1,3 2,0

NL4 M4 0,7 3,1 4,2 2,8 4,2 3,1 3,5
NL5 M5 0,8 6,0 6,8 5,4 6,8 6,0 5,6
NL6 M6 1,0 10,5 9,7 9,5 9,7 10,5 8,0
NL8 M8 1,25 25 18 23 18 25 15 Torque guidelines for other bolt
NL10 M10 1,5 49 28 45 28 50 23
grades are available on request
NL12 M12 1,75 85 40 77 40 85 33
NL14 M14 2,0 135 55 122 55 136 46 through your local NORD-LOCK
NL16 M16 2,0 205 75 185 75 208 62 representative.
NL18 M18 2,5 288 92 260 92 291 76
NL20 M20 2,5 402 118 363 118 408 97
NL22 M22 2,5 548 146 494 146 557 120
NL24 M24 3,0 693 169 625 169 703 140
NL27 M27 3,0 1 010 221 910 221 1028 182
NL30 M30 3,5 1379 269 1 243 269 1 401 222
GTP600 = graphite lubricant
NL33 M33 3,5 1855 333 1 669 333 1 889 275
GF = ratio of yield point
NL36 M36 4,0 2 394 392 2 156 392 2 436 324
μg = thread friction
NL39 M39 4,0 3 087 468 2 777 468 3145 387
NL42 M42 4,5 3 820 538 3 439 538 3 890 445
μw = washer friction

NORD-LOCK zinc flake coated (DP) with non-plated bolt 10.9 NORD-LOCK zinc flake coated (DP) with non-plated bolt 12.9

Oil, GF=0,71 GTP600, GF=0,75 Oil, GF=0,71 GTP600, GF=0,75

μg= 0,13, μw= 0,14 μg= 0,08, μw= 0,13 μg= 0,13, μw= 0,12 μg= 0,08, μw= 0,11
Washer Bolt Pitch Torque Clamp load Torque Clamp load Washer Bolt Pitch Torque Clamp load Torque Clamp load
size size [mm] [Nm] [kN] [Nm] [kN] size size [mm] [Nm] [kN] [Nm] [kN]

NL3 M3 0,5 1,8 3,2 1,6 3,4 NL3 M3 0,5 2,0 3,9 1,7 4,1
NL4 M4 0,7 4,1 5,6 3,6 5,9 NL4 M4 0,7 4,6 6,7 4,0 7,1
NL5 M5 0,8 8,1 9,1 7,0 9,6 NL5 M5 0,8 9,1 10,9 7,7 11,5
NL6 M6 1,0 14,1 12,9 12,3 13,6 NL6 M6 1,0 15,8 15,4 13,5 16,3
NL8 M8 1,25 34 23 30 25 NL8 M8 1,25 38 28 32 30
NL10 M10 1,5 67 37 58 39 NL10 M10 1,5 75 44 64 47
NL12 M12 1,75 115 54 99 57 NL12 M12 1,75 128 65 109 68
NL14 M14 2,0 183 74 158 78 NL14 M14 2,0 204 89 174 94
NL16 M16 2,0 279 100 240 106 NL16 M16 2,0 311 120 263 127
NL18 M18 2,5 391 123 337 130 NL18 M18 2,5 437 148 370 156
NL20 M20 2,5 547 156 470 165 NL20 M20 2,5 610 188 515 198
NL22 M22 2,5 745 194 639 205 NL22 M22 2,5 831 233 699 246
NL24 M24 3,0 942 225 809 238 NL24 M24 3,0 1 052 270 887 286
NL27 M27 3,0 1375 294 1176 310 NL27 M27 3,0 1533 352 1288 372
NL30 M30 3,5 1875 358 1608 378 NL30 M30 3,5 2091 430 1761 454
NL33 M33 3,5 2526 443 2157 468 NL33 M33 3,5 2 815 532 2362 562
NL36 M36 4,0 3259 522 2788 551 NL36 M36 4,0 3633 626 3053 662
NL39 M39 4,0 4203 624 3 588 659 NL39 M39 4,0 4683 748 3925 790
NL42 M42 4,5 5202 716 4445 757 NL42 M42 4,5 5799 860 4866 908

9
Nord-Lock stainless steel washers
EN 1.4404 (AISI 316L) or equivalent, surface hardened

EN 1.4404 is an austenitic chromium-nickel stainless steel containing molybdenum. NL3 ss – NL8ss

This stainless steel also has extra low carbon content in order to reduce the risk Øi ±0,1 mm
of chromium-carbide precipitation. EN 1.4404 is one of the most commonly used NL10 ss – NL42ss
stainless steel grades and Nord-Lock washers made of EN 1.4404 are suitable for Ø i ±0,2 mm Øi
most applications where no chlorides or acids are present. NL45ss – NL80ss
Øi+0,5 / -0,0 mm

Dimension chart
Washer size Bolt size øi øo Thickness T Min. Approx.
[mm] [mm] [mm] package weight NL3ss – NL24ss
Metric UNC [pairs] kg / 100 pairs Øo ± 0,2 mm
NL27ss – NL42ss
Øo ± 0,3 mm Øo
NL3ss M3 #5 3,4 7,0 2,2 200 0,04
NL3,5ss M3,5 #6 3,9 7,6 2,2 200 0,04 NL45 ss – NL80ss
Øo +0,0 / -2,0 mm
NL3,5spss M3,5 #6 3,9 9,0 2,2 200 0,07
NL4ss M4 #8 4,4 7,6 2,2 200 0,04
NL4spss M4 #8 4,4 9,0 2,2 200 0,07
NL5ss M5 #10 5,4 9,0 2,2 200 0,06 NL3ss – NL24ss
NL5spss M5 #10 5,4 10,8 2,2 200 0,11 T ± 0,25 mm
NL6ss M6 6,5 10,8 2,2 200 0,09 NL27ss – NL42ss
NL6spss M6 6,5 13,5 2,0 200 0,16 T +0,0 / -0,5 mm T
NL1/4”ss 1/4” 7,2 11,5 2,2 200 0,09 NL45ss – NL80ss
NL1/4”spss 1/4” 7,2 13,5 2,2 200 0,15 T ± 0,75 mm
NL8ss M8 5/16” 8,7 13,5 2,0 200 0,12
NL8spss M8 5/16” 8,7 16,6 2,0 200 0,22
NL3/8”ss 3/8” 10,3 16,6 2,0 200 0,19 • Please consult our website for current dimensions and 2D / 3D CAD
NL3/8”spss 3/8” 10,3 21,0 2,0 200 0,38 models: www.nord-lock.com/cad
NL10ss M10 10,7 16,6 2,0 200 0,18
NL10spss M10 10,7 21,0 2,0 200 0,37
NL11ss M11 7/16” 11,4 18,5 2,2 200 0,26
NL12ss M12 13,0 19,5 2,0 200 0,23
NL12spss M12 13,0 25,4 3,0 100 0,82 Torque guidelines
NL1/2”ss 1/2” 13,5 19,5 2,0 200 0,24 Nord-Lock stainless steel washers with stainless steel bolt,
NL1/2”spss 1/2” 13,5 25,4 3,2 100 0,80
lubricated with copper/graphite paste (Molykote® 1000).
NL14ss M14 9/16” 15,2 23,0 3,0 100 0,49
NL14spss M14 9/16” 15,2 30,7 3,2 100 1,31 A4-70, Cu/C paste, A4-80, Cu/C paste,
NL16ss M16 5/8” 17,0 25,4 3,0 100 0,59 GF =65% μth = 0,12, μb = 0,14 GF =65%, μth = 0,12, μb= 0,14
NL16spss M16 5/8” 17,0 30,7 3,2 100 1,13 Washer Bolt Pitch Torque Clamp load Torque Clamp load
size size [mm] [Nm] [kN] [Nm] [kN]
NL18ss M18 19,5 29,0 3,2 100 0,80
NL18spss M18 19,5 34,5 3,2 100 1,56
NL3/4”ss 3/4” 20,0 30,7 3,2 100 0,96 NL3 ss M3 0,5 1,5 1,5 1,7 2,0
NL3/4”spss 3/4” 20,0 39,0 3,2 100 2,10 NL4 ss M4 0,7 3,0 2,6 3,6 3,4
NL20ss M20 21,4 30,7 3,0 100 0,82 NL5 ss M5 0,8 5,5 4,1 6,7 5,5
NL20spss M20 21,4 39,0 3,2 100 2,06 NL6 ss M6 1,0 8,1 5,9 11,2 7,8
NL22ss M22 7/8” 23,4 34,5 3,2 100 1,23 NL8 ss M8 1,25 18 11 21 14
NL22spss M22 7/8” 23,4 42,0 3,2 50 2,23 NL10 ss M10 1,5 26 17 34 23
NL24ss M24 25,3 39,0 3,2 100 1,52 NL12 ss M12 1,75 41 25 62 33
NL24spss M24 25,3 48,5 3,2 50 3,50 NL14 ss M14 2,0 68 34 101 45
NL1”ss 1” 27,9 39,0 3,2 100 1,42 NL16 ss M16 2,0 108 46 157 61
NL1”spss 1” 27,9 48,5 3,2 50 3,22 NL18 ss M18 2,5 157 56 224 75
NL27ss M27 28,4 42,0 6,8 50 3,45 NL20 ss M20 2,5 223 72 318 95
NL27spss M27 28,4 48,5 6,8 25 5,85 NL22 ss M22 2,5 310 89 438 118
NL30ss M30 1 1/8” 31,4 47,0 6,8 50 4,43 NL24 ss M24 3,0 397 103 558 137
NL30spss M30 1 1/8” 31,4 58,5 6,8 25 9,53 NL27 ss M27 3,0 589 134 823 179
NL33ss M33 1 1/4” 34,4 48,5 6,8 25 4,25 NL30 ss M30 3,5 815 164 1132 219
NL36ss M36 1 3/8” 37,4 55,0 6,8 25 5,96 NL36ss M36 4,0 1445 239 1993 319
NL39ss M39 1 1/2” 40,4 58,5 6,8 25 6,74
NL42ss M42 43,2 63,0 6,8 25 7,96
NL45ss M45 1 3/4” 46,2 70,0 6,8 25 10,20 Cu/C paste = Copper/graphite paste (Molykote ® 1000)
NL48ss M48 49,6 75,0 6,8 25 12,00 GF = ratio of yield point
NL52ss M52 2” 53,6 80,0 9,0 1 20,10 μth = thread friction
NL56ss M56 2 1/4” 59,1 85,0 9,0 1 21,30 μb = washer friction
NL60ss M60 63,1 90,0 9,0 1 23,50
NL64ss M64 2 1/2” 67,1 95,0 9,0 1 25,80 1 N = 0,225 lb
NL68ss M68 71,1 100,0 9,0 1 28,20 1 Nm = 0,738 ft-lb
NL72ss M72 75,1 105,0 9,0 1 30,70
NL76ss M76 3” 79,1 110,0 9,0 1 33,30 Torque guidelines for other bolt grades are available through
NL80ss M80 3 1/8” 83,1 115,0 9,0 1 36,00 your local Nord-Lock representative.

Nord-Lock washers made of stainless steel are standard stock items,

yet subject to prior sale.

10
Nord-Lock washers joint guide

Tapped holes
Nord-Lock washers safely lock the bolt against the underlying surface.

Counter bores
The outer diameter of regular Nord-Lock washers is designed for counter-bore
holes according to DIN 974, i.e. the washers fit under the head of standard bolts.

Through holes
As for all locking washers, through holes require two pairs of Nord-Lock washers – one pair
for securing the bolt and a second pair for securing the nut.
Turn both fasteners in order to close the cams on both washer pairs before tightening to
minimize settlements. Keep the nut secured while tightening the bolt.

Stud bolts
Nord-Lock washers safely lock the nut on stud bolts and eliminate the need for adhesives.

Applications with large / slotted holes or soft underlying surfaces

To optimize the load distribution for applications with large / slotted holes
or with soft underlying surface, use a flanged nut / bolt together with
Nord-Lock “SP” washers with enlarged outer diameter.

Large / slotted holes Soft underlying surfaces

Designs where Nord-Lock washers are not recommended

• Mating surfaces that are not locked in place (see left figure)
• Mating surfaces harder than the washers
• Very soft mating surface, e.g. wood, plastic
• Applications with extremely large settlements
• Non-preloaded joints

If your application corresponds to one or more of the mentioned design critera, contact your
Nord-Lock representative and we will help you find an alternative solution.
12
Nord-Lock washers with enlarged outer diameter
Nord-Lock washers are available with an enlarged outer diameter, A flanged nut and Nord-Lock
referred to as SP washers. SP washers are designed for use SP washers increase the load
on large / slotted holes, painted / sensitive surfaces or soft supporting surface for
applications with slotted holes.
materials. Use Nord-Lock SP washers with flanged bolts or
nuts for optimum load distribution.
Ø inner regular = Ø inner sp
Ø outer regular < Ø outer sp

By using SP washers, the load is distributed over a larger surface which

can be more gentle for sensitive surfaces. Please consult Nord-Lock to
find the optimal solution for your application.

Nord-Lock SP Nord-Lock SP Nord-Lock SP

washers on soft metal. washers on painted washers on fibre
surface. surface.

Uniform friction with Nord-Lock washers

It is important to have control over the friction conditions in order to obtain the desired preload when tightening a joint.

Untightening Tightening When no washer is used under the fastener, the friction depends on
the contact surface. At a given torque, the obtained preload will vary
depending on the contact material.
Load [kN]

Regular nut
M8 on steel
without
washer

Regular nut M8
on aluminium
without washer

Torque [Nm]

Untightening Tightening When using Nord-Lock washers, sliding always occurs between the
upper washer and the bolt head / nut. At a given torque, the preload
will be the same, regardless of the contact material.
Regular nut M8
on steel with
Nord-Lock
Nord-Lock provides customized torque guidelines for your application,
washers
contact your nearest representative.

Regular nut M8 on
aluminium with
Nord-Lock washers

Torque [Nm] 13
Nord-Lock® washers
Nord-Lock® washers can be used on standard grade as well as high grade bolts.
Assembly examples

Nord-Lock® can be used Nord-Lock® can also be Please note that Nord-
with bolts in tapped used in counter-bored Lock® cannot be used
holes. holes. on washers that are not
locked in place.

Nord-Lock® secures Use Nord-Lock® to lock For larger holes or

bolts and nuts in the nut, and there is on soft materials, use
through holes. no need for adhesives a flange nut/bolt in
Note: Keep the bolt to lock the stud bolt. combination with Nord-
secured when Nord-Lock® secures the Lock® sp (washers with
tightening the nut. joint. larger outer diameter).

Advantages
• Resists loosening caused by vibration and dynamic loads
• Ease of assembly and disassembly
• Locking function is not lost by lubrication
• Positive locking at low or high preload levels
• Same temperature characteristics as standard bolt/nut
• Minimum surface marring or scratching
• Reusable
• Achieves maximum safety when locking fasteners

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