DIN 25201 NORD-LOCK Original Type Washer

DIN 25201 wedge lock washers secure threaded connections under load. They are used in industry and construction where increased connection reliability is required under vibration loads.

The Nord-Lock design uses a wedge configuration: the washer creates bolt tension and prevents it from self-loosening during operation.

Advantages of DIN 25201 washers:

• Connection reliability
• Resistance to vibration loads
• Easy installation
• Long service life
• Compatibility with various bolt types

The material is carbon steel or stainless steel, with optional protective zinc coating. This allows the washers to be used in various operating conditions, including aggressive environments. The washer diameter is selected according to the size of the matching bolt.

FLOK supplies original Nord-Lock products as well as equivalents meeting the standard’s requirements.

DIN 25201 wedge lock washers, NORD-LOCK type

The 2fix anti-vibration washer DIN 25201 Nord-Lock secures the bolted connection through tension. The system consists of two washers with wedges on one side and radially arranged teeth on the other side. The wedge-lock effect occurs because the wedge angle «α» is greater than the thread pitch «β». This reliably prevents the threaded connection from self-loosening.

Comparative analysis of connections using 2fix washers and spring lock washers

2fix lock washers	Spring lock washer
Wedge-lock technology	Not suitable for critical connections
Secure bolted connection under vibration and dynamic loads	Risk of contact surface deformation
Prevents the bolted connection from rotating relative to the part	Risk of the spring lock washer being squeezed out from under the nut
Possibility of adjustment or maintenance of the mechanism	Cannot be reused
Eliminates spontaneous loosening	Reduced friction (frictional engagement, friction) and no effect when a plain washer is placed under the spring lock washer

Advantages of 2fix lock washers compared to the Swedish-made equivalent

2fix lock washers	Nord-Lock lock washers
Manufactured to DIN 25201	Manufactured to DIN 25201
Technical test certificate to ISO 16130:2015
Available in sizes from M3 to M130	Available in sizes from M3 to M130
Registered in the Russian Register of Technical Specifications of the Certification System, TU 25.94.12-001-7318210009-2023	No representatives in Russia or Belarus; supply only possible through intermediaries
Delivery time: from stock, 1 day after payment	Unpredictable delivery times (from 2 months)

Advantages of 2fix lock washers compared to a set of: Type 2 bolt, castle nut, cotter pin

2fix Nord-Lock lock washer, Type 1 bolt 12x40, nut	Type 2 bolt 12x40, washer, castle nut, cotter pin
Assembly time: 30 seconds	Assembly time: 90 seconds

Size table

d	d1	d2	s
M3	3.4	7.0	1.8
M4	4.4	7.6	1.8
M4 SP	4.4	9.0	1.8
M5	5.4	9.0	1.8
M5 SP	5.4	10.8	1.8
M6	6.5	10.8	1.8
M6 SP	6.5	13.5	2.5
M8	8.7	1.3.5	2.5
M8 SP	8.7	16.6	2.5
M10	10.7	16.6	2.5
M10 SP	10.7	21.0	2.5
M12	13.0	19.5	2.5
M12 SP	13.0	25.4	3.4
M14 SP	15.2	30.7	3.4
M16	17.0	25.4	3.4
M16 SP	17.0	30.7	3.4
M20	21.4	30.7	3.4
M20 SP	21.4	39.0	3.4
M22 SP	23.4	42.0	4.6
M24	25.3	39.0	3.4
M24 SP	25.3	48.5	4.6
M27	28.4	42.0	6.6
M30	31.4	47.0	6.6
M33	34.4	48.5	6.6
M36	37.4	55.0	6.6

Materials and comparative characteristics of Nord-Lock wedge lock washers

Specifications	Steel washers	Stainless steel washers (ss)	254 SMO® washers	INCONEL®/HASTELLOY® C-276 washers	INCONEL® 718 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
Application examples	Standard steel structures	Standard stainless steel structures. Chlorine-free / acid-free environment	Standard structures for salt water, pumps, heat exchangers, nuclear facilities, desalination equipment, food production and medical equipment	Standard structures related to acidic environments, processing and chemical industry, evaporators, deep-well equipment	Structures related to high temperatures, gas turbines, turbochargers, incineration furnaces
Used for bolts with sizes	M3-M130	M3-M80	M3-M39	M3-M39 available to order	M3-M39 available to order
Washer types	Washers with standard outer diameter (NL3–NL130) Washers with increased outer diameter (NL3.5sp–NL36sp)	Washers with standard outer diameter (NL3ss–NL80ss) Washers with increased outer diameter (NL3.5spss–NL30spss)	Washers with standard outer diameter (NL3ss-254–NL39ss-254) Washers with increased outer diameter (NL3.5spss-254– NL27spss-254)	Washers with standard outer diameter (NL3ss-276–NL39ss-276) Washers with increased outer diameter (NL3.5spss-276– NL27spss-276)	Washers with standard outer diameter (NL3ss-718–NL39ss-718) Washers with increased outer diameter (NL3.5spss-718– NL27spss-718)
Processing/protective coating	Through hardening, Delta Protekt® base coat (KL100) and top coat (VH302GZ)	Surface hardening	Surface hardening	Surface hardening	Surface hardening
Washer hardness	≥ 465 HV1	≥ 520HV0.05	≥ 600HV0.05	≥ 520HV0.05	≥ 620HV0.05
Corrosion resistance properties	Minimum 600 hours of salt spray testing (to ISO 9227)	PREN 27	PREN 45	PREN 68	PREN 29
Bolt property classes	Up to 12.9	Up to A4-80	Up to A4-80	Up to A4-80	Up to A4-80
Temperature range	-20°C to 200°C	-160°C to 500°C	-160°C to 500°C	-160°C to 500°C	-160°C to 700°C

Dimensions of Nord-Lock wedge-locking washers, EN 1.7182 steel or equivalent, zinc flake coating (Delta Protekt®), hardened

Washer size	Bolt size	Øi, mm	Øo, mm	Thickness T, mm	Min. packaging (in pairs)	Weight kg/100 pairs
NL3	M3	3.4	7.0	1.8	200	0.03
NL3.5	M3.5	3.9	7.6	1.8	200	0.04
NL3.5sp	M3.5	3.9	9.0	1.8	200	0.06
NL4	M4	4.4	7.6	1.8	200	0.04
NL4sp	M4	4.4	9.0	1.8	200	0.06
NL5	M5	5.4	9.0	1.8	200	0.05
NL5sp	M5	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
NL8	M8	8.7	13.5	2.5	200	0.15
NL8sp	M8	8.7	16.6	2.5	200	0.28
NL10	M10	10.7	16.6	2.5	200	0.22
NL10sp	M10	10.7	21.0	2.5	200	0.47
NL11	M11	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	0.93
NL14	M14	15.2	23.0	3.4	100	0.56
NL14sp	M14	15.2	30.7	3.4	100	1.41
NL16	M16	17.0	25.4	3.4	100	0.67
NL16sp	M16	17.0	30.7	3.4	100	1.28
NL18	M18	19.5	29.0	3.4	100	0.85
NL18sp	M18	19.5	34.5	3.4	100	1.58
NL20	M20	21.4	30.7	3.4	100	0.93
NL20sp	M20	21.4	39.0	3.4	100	2.03
NL22	M22	23.4	34.5	3.4	100	1.29
NL22sp	M22	23.4	42.0	4.6	50	3.31
NL24	M24	25.3	39.0	3.4	100	1.68
NL24sp	M24	25.3	48.5	4.6	50	4.51
NL27	M27	28.4	42.0	5.8	50	3.29
NL27sp	M27	28.4	48.5	5.8	25	5.39
NL30	M30	31.4	47.0	5.8	50	4.20
NL30sp	M30	31.4	58.5	6.6	25	8.96
NL33	M33	34.4	48.5	5.8	25	3.97
NL33sp	M33	34.4	58.5	6.6	25	8.31
NL36	M36	37.4	55.0	5.8	25	5.59
NL36sp	M36	37.4	63.0	6.6	25	9.15
NL39	M39	40.4	58.5	5.8	25	6.28
NL42	M42	43.2	63.0	5.8	25	7.47
NL45	M45	46.2	70.0	7.0	25	10.20
NL48	M48	49.6	75.0	7.0	25	12.00
NL52	M52	53.6	80.0	7.0	25	13.00
NL56	M56	59.1	85.0	7.0	10	13.50
NL60	M60	63.1	90.0	7.0	10	15.20
NL64	M64	67.1	95.0	7.0	10	16.70
NL68	M68	71.1	100.0	9.5	1	28.19
NL72	M72	75.1	105.0	9.5	1	30.70
NL76	M76	79.1	110.0	9.5	1	33.31
NL80	M80	83.1	115.0	9.5	1	36.02
NL85	M85	88.1	120.0	9.5	1	37.84
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

Tolerances for Nord-Lock locking washers:

NL3 – NL8 Øi ±0.1 mm; NL10 – NL42 Øi ±0.2 mm; NL45 – NL130 Øi +0.5 / -0.0 mm.

NL3 – NL24 Øo ± 0.2 mm; NL27 – NL42 Øo ± 0.3 mm; NL45 – NL130 Øo +0.0 / -2.0 mm.

NL3 – NL42 T ± 0.25 mm; NL45 – NL130 T ± 0.75 mm.

Nord-Lock washers with a thickness of 6.6 mm have a thickness tolerance of +0.0 / -0.5 mm.

Tightening torque for zinc-plated 8.8 bolts with Nord-Lock wedge-locking washers (zinc flake coated steel)

Washer size	Bolt size	Thread pitch, mm	Oil GF=75% μth= 0.10, μb = 0.16		Cu/C lubricant, GF=75% μth = 0.11, μb = 0.16		Dry, GF=62% μth = 0.15, μb= 0.18
			Torque, Nm	Axial force, kN	Torque, Nm	Axial force, kN	Torque, Nm	Axial force, kN
NL3	M3	0.5	1.3	2.4	2.1	2.4	1.3	2.0
NL4	M4	0.7	3.1	4.2	4.4	4.2	3.1	3.5
NL5	M5	0.8	6.0	6.8	8.0	6.8	6.0	5.6
NL6	M6	1.0	10.5	9.7	13.2	9.7	10.5	8.0
NL8	M8	1.25	25	18	30	18	25	15
NL10	M10	1.5	49	28	49	28	50	23
NL12	M12	1.75	85	40	83	40	85	33
NL14	M14	2.0	135	55	131	55	136	46
NL16	M16	2.0	205	75	197	75	208	62
NL18	M18	2.5	288	92	275	92	291	76
NL20	M20	2.5	402	118	382	118	408	97
NL22	M22	2.5	548	146	517	146	557	120
NL24	M24	3.0	693	169	652	169	703	140
NL27	M27	3.0	1010	221	945	221	1028	182
NL30	M30	3.5	1379	269	1286	269	1401	222
NL33	M33	3.5	1855	333	1722	333	1889	275
NL36	M36	4.0	2394	392	2219	392	2436	324
NL39	M39	4.0	3087	468	2852	468	3145	387
NL42	M42	4.5	3820	538	3525	538	3890	445

Cu/C lubricant = copper-graphite lubricant (Molykote® 1000)

GF = yield ratio

μth = thread friction

μb = washer friction

1 N = 0.225 lb

1 Nm = 0.738 ft-lb

Dimensions of Nord-Lock 254 SMO® stainless locking washers, EN 1.4547 steel or equivalent, surface hardened

Washer size	Bolt size	Øi, mm	Øo, mm	Thickness T, mm	Min. packaging (in pairs)	Weight kg/100 pairs
NL3ss-254	M3	3.4	7.0	2.2	200	0.04
NL3.5ss-254	M3.5	3.9	7.6	2.2	200	0.04
NL3.5spss-254	M3.5	3.9	9.0	2.2	200	0.07
NL4ss-254	M4	4.4	7.6	2.2	200	0.04
NL4spss-254	M4	4.4	9.0	2.2	200	0.07
NL5ss-254	M5	5.4	9.0	2.2	200	0.06
NL5spss-254	M5	5.4	10.8	2.2	200	0.11
NL6ss-254	M6	6.5	10.8	2.2	200	0.09
NL6spss-254	M6	6.5	13.5	2.2	200	0.16
NL8ss-254	M8	8.7	13.5	2.0	200	0.12
NL8spss-254	M8	8.7	16.6	2.2	200	0.22
NL10ss-254	M10	10.7	16.6	2.0	200	0.18
NL10spss-254	M10	10.7	21.0	2.2	200	0.37
NL11ss-254	M11	11.4	18.5	2.2	200	0.26
NL12ss-254	M12	13.0	19.5	2.0	200	0.23
NL12spss-254	M12	13.0	25.4	3.0	100	0.82
NL14ss-254	M14	15.2	23.0	3.0	100	0.49
NL14spss-254	M14	15.2	30.7	3.2	100	1.31
NL16ss-254	M16	17.0	25.4	3.0	100	0.59
NL16spss-254	M16	17.0	30.7	3.2	100	1.13
NL18ss-254	M18	19.5	29.0	3.2	100	0.80
NL18spss-254	M18	19.5	34.5	3.2	100	1.56
NL20ss-254	M20	21.4	30.7	3.0	100	0.82
NL20spss-254	M20	21.4	39.0	3.2	100	1.98
NL22ss-254	M22	23.4	34.5	3.2	100	1.19
NL22spss-254	M22	23.4	42.0	3.2	50	2.44
NL24ss-254	M24	25.3	39.0	3.2	100	1.65
NL24spss-254	M24	25.3	48.5	3.2	50	3.50
NL27ss-254	M27	28.4	42.0	5.8	50	3.10
NL27spss-254	M27	28.4	48.5	5.8	25	5.85
NL30ss-254	M30	31.4	47.0	5.8	50	4.04
NL33ss-254	M33	34.4	48.5	5.8	25	4.25
NL36ss-254	M36	37.4	55.0	5.8	25	5.96
NL39ss-254	M39	40.4	58.5	5.8	25	6.74

Tolerances for Nord-Lock 254 SMO® stainless washers:

NL3ss-254 – NL8ss-254 Øi ±0.1 mm; NL10ss-254 – NL39ss-254 Øi ±0.2 mm.

NL3ss-254 – NL24ss-254 Øo ± 0.2 mm; NL27ss-254 – NL39ss-254 Øo ± 0.3 mm.

NL3ss-254 – NL39ss-254 T ± 0.25 mm.

Tightening torque for stainless bolts with Nord-Lock 254 SMO® stainless washers coated with copper-graphite lubricant (Molykote® 1000)

Washer size	Bolt size	Thread pitch, mm	A4-70, Cu/C lubricant, GF=65% μth = 0.12, μb = 0.14		A4-80, Cu/C lubricant, GF=65% μth = 0.12, μb = 0.14
			Torque, Nm	Axial force, kN	Torque, Nm	Axial force, kN
NL3ss-254	M3	0.5	1.5	1.5	1.7	2.0
NL4ss-254	M4	0.7	3.0	2.6	3.6	3.4
NL5ss-254	M5	0.8	5.5	4.1	6.7	5.5
NL6ss-254	M6	1.0	8.1	5.9	11.2	7.8
NL8ss-254	M8	1.25	18	11	21	14
NL10ss-254	M10	1.5	26	17	34	23
NL12ss-254	M12	1.75	41	25	62	33
NL14ss-254	M14	2.0	68	34	101	45
NL16ss-254	M16	2.0	108	46	157	61
NL18ss-254	M18	2.5	157	56	224	75
NL20ss-254	M20	2.5	223	72	318	95
NL22ss-254	M22	2.5	310	89	438	118
NL24ss-254	M24	3.0	397	103	558	137
NL27ss-254	M27	3.0	589	134	823	179
NL30ss-254	M30	3.5	815	164	1132	219
NL36ss-254	M36	4.0	1445	239	1993	319

Cu/C lubricant = copper-graphite lubricant (Molykote® 1000)

GF = yield ratio

μth = thread friction

μb = washer friction

1 N = 0.225 lb

1 Nm = 0.738 ft-lb

Materials and properties of Nord-Lock X-series spring lock washers, carbon steel

Steel type	Application examples	Washer types	Treatment Protective coating	Washer hardness	Corrosion resistance	Strength	Temperature range
EN 1.7225 or equivalent	General steel applications	Standard outer diameter Increased outer diameter (sp)	Through-hardened Base coat Delta Protekt® (KL100) and top coat (VH302GZ)	≥ 485 HV1	At least 600 hours in salt spray test (per ISO 9227)	Up to 12.9	From -40°C to 150°C

Dimensions of Nord-Lock X-series spring lock washers, EN 1.7225 carbon steel or equivalent, zinc coating (Delta Protekt®), through-hardened

Washer size	Bolt size	Øi, mm	Øo, mm	Thickness T, mm	Min. packaging (in pairs)	Weight kg/100 pairs
NLX6	M6	6.3	10.8	1.8	200	0.08
NLX6sp	M6	6.3	13.5	2.2	200	0.17
NLX8	M8	8.4	13.5	2.3	200	0.14
NLX8sp	M8	8.4	16.6	2.3	200	0.27
NLX10	M10	10.5	16.6	3.0	200	0.28
NLX10sp	M10	10.5	21.0	3.5	200	0.66
NLX12	M12	12.5	19.5	3.5	200	0.45
NLX12sp	M12	12.5	25.4	4.2	100	1.17
NLX14	M14	14.6	23.0	4.1	100	0.72
NLX16	M16	16.6	25.4	4.8	100	1.01
NLX16sp	M16	16.6	30.7	4.8	100	1.84
NLX20	M20	20.7	30.7	6.1	100	1.75
NLX20sp	M20	20.7	39.0	6.1	50	3.81

Tolerances for Nord-Lock X-series locking washers:

NLX6 – NLX20 Øi ±0.2 mm

NLX6 – NLX20 Øo ± 0.2 mm

NLX6 – NLX16sp T +0.00/-0.4 mm; NLX20 – NLX20sp T +0.00/-0.5 mm

Tightening torque for 8.8 bolts with Nord-Lock X-series spring lock washers (zinc flake coated carbon steel)

Washer size	Bolt size	Thread pitch, mm	Oil GF=75% μth= 0.10, μb = 0.16		Cu/C lubricant, GF=75% μth = 0.11, μb = 0.16		Dry, GF=62% μth = 0.15, μb= 0.18
			Torque, Nm	Axial force, kN	Torque, Nm	Axial force, kN	Torque, Nm	Axial force, kN
NLX6	M6	1.0	10.5	9.7	13.2	9.7	10.5	8.0
NLX8	M8	1.25	25	18	30	18	25	15
NLX10	M10	1.5	49	28	49	28	50	23
NLX12	M12	1.75	85	40	83	40	85	33
NLX14	M14	2.0	135	55	131	55	136	46
NLX16	M16	2.0	205	75	197	75	208	62
NLX20	M20	2.5	402	118	382	118	408	97

Tightening torque for 10.9 bolts with Nord-Lock X-series spring lock washers (zinc flake coated carbon steel)

Washer size	Bolt size	Thread pitch, mm	Oil GF=71% μth= 0.13, μb = 0.14		Cu/C lubricant, GF=75% μth = 0.11, μb = 0.15
			Torque, Nm	Axial force, kN	Torque, Nm	Axial force, kN
NLX6	M6	1.0	14.1	12.9	20.1	13.6
NLX8	M8	1.25	34	23	44	25
NLX10	M10	1.5	67	37	73	39
NLX12	M12	1.75	115	54	121	57
NLX14	M14	2.0	183	74	188	78
NLX16	M16	2.0	279	100	281	106
NLX20	M20	2.5	547	156	534	165

Tightening torque for 12.9 bolts with Nord-Lock X-series spring lock washers (zinc flake coated carbon steel)

Washer size	Bolt size	Thread pitch, mm	Oil GF=71% μth= 0.13, μb = 0.12		Cu/C lubricant, GF=75% μth = 0.11, μb = 0.15
			Torque, Nm	Axial force, kN	Torque, Nm	Axial force, kN
NLX6	M6	1.0	15.8	15.4	21.8	16.3
NLX8	M8	1.25	38	28	47	30
NLX10	M10	1.5	75	44	93	47
NLX12	M12	1.75	128	65	151	68
NLX14	M14	2.0	204	89	232	94
NLX16	M16	2.0	311	120	342	127
NLX20	M20	2.5	610	188	638	198

Cu/C lubricant = copper-graphite lubricant (Molykote® 1000)

GF = yield ratio

μth = thread friction

μb = washer friction

1 N = 0.225 lb

1 Nm = 0.738 ft-lb