Twin-Wedge (Paired) Lock Washer Twin Lock

The Twin Lock twin-wedge lock washer is an Italian copy of the Nord Lock brand product. These fasteners are purchased in pairs and installed with their inner teeth facing each other. As the threaded fastener is tightened, the locking elements shift relative to one another, reinforcing the joint.

This feature helps secure the joint more reliably and prevents bolts and nuts from self-loosening even under demanding operating conditions. The same purpose is served by the teeth radially positioned on the outer side of the Twin Lock washer. The diameter of the center hole must match the size of the metric fastener.

Types of Twin Lock twin-wedge washers

FLOK supplies two types of paired lock washers: standard versions and large-diameter versions. Standard washers are made of carbon steel with a hardness of 465–550 HV 10, hardened and tempered, as well as of AISI 316 chromium-nickel steel. This type of washer is used with bolts, screws and studs with metric thread sizes from M5 to M36.

Twin Lock twin-wedge lock washers with a larger outer diameter are better suited for joining loose materials and holes fitted with slots. The materials used are the same as for standard washers. Both carbon-steel variants are additionally protected against corrosion by electroplated zinc coating. These products are used with bolted fasteners with threads from M6 to M20.

The advantages of this fastener include reliable locking during tightening with forces ranging from low to very high. It offers high performance and installation qualities, as well as reusability. The washer protects the surface of the base material from deformation and can operate under a wide range of temperature fluctuations.

Where Twin Lock twin-wedge lock washers are used

Paired washers are made from various materials, so their application extends to any sector of the economy. The main function of the product is to ensure tight fixation and locking of the threaded fastening joint. The Twin Lock twin lock washer is a versatile fastener. Fasteners using it can withstand significant dynamic loads, including vibration.

The main materials used to manufacture the washers are carbon steels with or without corrosion protection by zinc or chromium, as well as austenitic alloys. If the fastening of materials requires non-magnetic properties, fasteners made of chromium-nickel stainless steel should be used.

Available sizes of the Twin Lock lock washer:

Washer size	Thread diameter, mm	Thread diameter, inches	”d min.- max."	"D min.- max."	"Steel h pair min.- max."	"A4 h pair min.- max.”	Packaging
3.4x7.0	M3	#5	3.3-3.5	6.8-7.2	1.55-2.05	1.75-2.25	200
3.9x7.6	M3.5	#6	3.8-4.0	7.4-7.8	1.55-2.05	1.75-2.25	200
3.9x9.0			3.8-4.0	8.8-9.2	1.55-2.05	1.75-2.25	200
4.4x7.6	M4	#8	4.3-4.5	7.4-7.8	1.55-2.05	1.75-2.25	200
4.4x9.0			4.3-4.5	8.8-9.2	1.55-2.05	1.75-2.25	200
5.4x9.0	M5	#10	5.3-5.5	8.8-9.2	1.55-2.05	1.75-2.25	200
5.4x10.8			5.3-5.5	10.6-11.0	1.55-2.05	1.75-2.25	200
6.5x10.8	M6		6.4-6.6	10.6-11.0	1.55-2.05	1.75-2.25	200
6.5x13.5			6.4-6.6	13.3-13.7	2.25-2.75	1.75-2.25	200
7.2x11.5	1/4”		7.1-7.3	11.3-11.7	1.55-2.05	1.75-2.25	200
7.2x13.5	-		7.1-7.3	13.3-13.7	1.55-2.05	1.75-2.25	200
8.7x13.5	M8	5/16”	8.6-8.8	13.3-13.7	2.25-2.75	1.75-2.25	200
8.7x16.6			8.6-8.8	16.4-16.8	2.25-2.75	1.75-2.25	200
10.3x16.6	3/8”		10.2-10.4	16.4-16.8	2.25-2.75	1.75-2.25	200
10.3x21.0			10.2-10.4	20.8-21.2	2.25-2.75	1.75-2.25	200
10.7x16.6	M10		10.5-10.9	16.4-16.8	2.25-2.75	1.75-2.25	200
10.7x21.0			10.5-10.9	20.8-21.2	2.25-2.75	1.75-2.25	200
11.4x18.5	M11	7/16”	11.2-11.6	18.3-18.7	2.25-2.75	1.75-2.25	200
13.0x19.5	M12		12.8-13.2	19.3-19.7	2.25-2.75	1.75-2.25	200
13.0x25.4			12.8-13.2	25.2-25.6	3.15-3.65	2.75-3.25	100
13.5x19.5	1/2”		13.3-13.7	19.3-19.7	2.25-2.75	1.75-2.25	200
13.5x25.4			13.3-13.7	25.2-25.6	3.15-3.65	2.75-3.25	100
15.2x23.0	M14	9/16”	15.0-15.4	22.8-23.2	3.15-3.65	2.75-3.25	100
15.2x30.7	-	-	15.0-15.4	30.5-30.9	3.15-3.65	2.75-3.25	100
17.0x25.4	M16	5/8”	16.8-17.2	25.2-25.6	3.15-3.65	2.75-3.25	100
17.0x30.7			16.8-17.2	30.5-30.9	3.15-3.65	2.75-3.25	100
19.5x29.0	M18		19.3-19.7	28.8-29.2	3.15-3.65	2.75-3.25	100
19.5x34.5			19.3-19.7	34.3-34.7	3.15-3.65	2.75-3.25	100
20.0x30.7	3/4		19.8-20.2	30.5-30.9	3.15-3.65	2.75-3.25	100
20.0x39.0			19.8-20.2	38.8-39.2	3.15-3.65	2.75-3.25	100
21.4x30.7	M20		21.2-21.6	30.5-30.9	3.15-3.65	2.75-3.25	100
21.4x39.0			21.2-21.6	38.8-39.2	3.15-3.65	2.75-3.25	100
23.4x34.5	M22	7/8”	23.2-23.6	34.3-34.7	3.15-3.65	2.75-3.25	100
23.4x42.0			23.2-23.6	41.8-42.2	4.35-4.85	2.75-3.25	50
25.3x39.0	M24		25.1-25.5	38.8-39.2	3.15-3.65	2.75-3.25	100
25.3x48.5			25.1-25.5	48.3-48.7	4.35-4.85	2.75-3.25	50
27.9x39.0	1		27.7-28.1	38.8-39.2	3.15-3.65	2.75-3.25	100
27.9x48.5			27.7-28.1	48.3-48.7	4.35-4.85	2.75-3.25	50
28.4x42.0	M27		28.2-28.6	41.7-42.3	5.55-6.05	6.30-6.80	50
28.4x48.5			28.2-28.6	48.2-48.8	5.55-6.05	6.30-6.80	25
31.4x47.0	M30	1 1/8”	31.2-31.6	46.7-47.3	5.55-6.05	6.30-6.80	50
31.4x58.5			31.2-31.6	58.2-58.8	6.35-6.85	6.30-6.80	25
34.4x48.5	M33	1 1/4”	34.2-34.6	48.2-48.8	5.55-6.05	6.30-6.80	25
34.4x58.5			34.2-34.6	58.2-58.8	6.35-6.85		25
37.4x55.0	M36	1 1/8”	37.2-37.6	54.7-55.3	6.35-6.85	6.30-6.80	25
37.4x63.0			37.2-37.6	62.7-63.3	6.35-6.85		25
40.4x58.5	M39	1 1/2”	40.2-40.6	58.2-58.8	6.35-6.85	6.30-6.80	25
43.2x63.0	M42		43.0-43.4	62.7-63.3	6.35-6.85	6.30-6.80	25

The equivalent of the Twin Lock lock washer is the Nord Lock twin-wedge lock washer (full equivalent).

How to buy Twin Lock twin-wedge lock washers

FLOK supplies washers and other fasteners in any batch size: small and large wholesale lots, as well as retail. All products are certified in accordance with the requirements of current standards.