Single Internal Tab Washer? The 128 Correct Answer

Are Nord-Lock washers reusable?

The short answer is yes. You can normally reuse Nord-Lock washers, but it is necessary to first carefully inspect both washers in the pair for signs of damage. Damaged or worn washers should not be reused as this may affect wedgelock performance and expose your bolted joints to loosening.

Because the Nord-Lock is a removable system, assemblies secured with wedge lock washers can be easily disassembled with a torque wrench. Loosening Nord-Lock washers is as easy as tightening. Note that the loosening torque is generally lower than the tightening torque as the locking function is not based on increased friction.

The pre-assembled discs are installed in pairs, cam face to cam face. After the first use, the pre-assembly adhesive is no longer effective and the pair of washers will come loose.

Before reassembly, check the reusability of all components of the assembly, including the Nord-Lock washers. Check that the cams on the inside of the washers are not completely worn, rusted or partially damaged, then check the serrations on the back.

Once the components have been inspected, the assembly can be reassembled and reused. Be sure to reinstall the washers correctly, cam face to cam face with the serrations facing out.

How many times can a Nord-Lock washer be reused?

There is no definitive answer as to how many times you can reuse the washers. Quite simply, you should check the condition of both washers in the pair each time you intend to disassemble and reuse the application.

However, there are steps you can take to increase the likelihood that your washers will stay in good condition and be reusable. Nord-Lock recommends using a high quality anti-seize lubricant to minimize changes in friction conditions and improve tightening.

Lubrication is particularly beneficial for large bolts and stainless steel applications. Although the Nord-Lock wedge-locking feature provides secure locking in both dry and lubricated conditions, the benefits of lubricated fasteners include:

Improved reusability

Reduced friction and deviation

Easier assembly and disassembly

Reduced torsional stress due to minimized thread friction

Avoids abrasion and thread scuffing

Additional protection against corrosion

For further technical assistance with wedge-lock washers or other bolting technology, contact an experienced Nord-Lock engineer at one of our Global Technical Centers now

The lock washer should be loosened with a flathead screwdriver. If you want to remove a spring washer, put the screwdriver head under it. If you want to remove a toothed washer, place the head under one of the teeth. If the screwdriver head does not open immediately, you should work it under the washer.

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DIN 93 locking plates

We manufacture locking plates according to DIN 93 from high-quality standard material or special material. Lock washers mainly made of carbon steel, alloy steel, stainless steel, austenitic steel and other standard materials. We also offer non-standard lock washers for special needs. DIN 93 is a round lock washer with an additional tab or notch that primarily helps hold the nut in place and provides a positive locking device. DIN 93 has a single long tab on the outer surface to prevent an assembly from rotating. The outer diameter of the DIN 93 is almost twice the inner diameter.

We mainly manufacture and export two types of washers including Outer Link Washers and Inner Link Washers. We also offer a combination of outer and inner disc tab to meet customer’s specific needs. The tabs or notches of the tab washers are bent over the mating pieces to form a strong connection around the bolts and nuts. DIN 93 is an external lock washer type or standard. DIN 93 Lock Washers are available in several variations, single, multiple, shaped and flat.

DIN 93 washers are removable and reusable. We offer the range of DIN 93 Locking Plates with a variety of materials, thickness, tabs, sizes, designs, strength, finishes and other configurations. DIN 93 Tab Washers are available with different types of plating, finishing or coating options such as: B. Tin, Zinc (Yellow, White, Blue, Black), Hot Dip Galvanized, Chrome, Nickel Brass, Black Oxide, Electro Tin, Phosphate, Powder Coating and others as required. We also manufacture custom lock washers that perfectly match the customer’s design and specifications.

Thin plate with a hole, typically used to distribute the load of a threaded fastener

Assorted washers: flat, split, star and insulating

A washer is a thin plate (usually disc-shaped but sometimes square) with a hole (usually in the center) that is typically used to take the load of a threaded fastener, such as a fastener. B. a screw or nut to distribute. Other uses are as a spacer, spring (Belleville washer, wave washer), wear pad, preload indicator, locking device and to reduce vibration (rubber washer).

Washers are usually made of metal or plastic. High quality bolted connections require hardened steel washers to prevent loss of preload due to knurling after torque is applied. Washers are also important to prevent galvanic corrosion, especially when isolating steel bolts from aluminum surfaces. They can also be used as bearings in rotating applications. A thrust washer is used when a roller bearing is not required for cost-benefit reasons or for reasons of space. Coatings can be used to reduce wear and friction, either by hardening the surface or by providing a solid lubricant (i.e., a self-lubricating surface).

The origin of the word is unknown; The first recorded use of the word was in 1346, however its definition was first recorded in 1611.[1]

Rubber or fiber gaskets used in faucets (or faucets or valves) to seal against water leaks are sometimes colloquially referred to as washers; But while they may look similar, washers and gaskets are usually designed for different functions and manufactured differently.

Washing machine types[ edit ]

Most washers can be classified into three broad types;

Washers, which distribute a load and prevent damage to the surface being fastened, or provide some form of isolation, e.g. B. electric

that distribute a load and prevent damage to the surface to be fastened, or provide some form of insulation, such as

that are axially flexible and used to prevent tightening or loosening due to vibration lock washers that prevent tightening or loosening by preventing unscrewing rotation of the fastener; Lock washers are usually also spring washers.

Washers [ edit ]

Name(s) Image Description Washer (or “flat washer”) A flat ring or ring, often metal, used to distribute the load of a bolted fastener. Additionally, a washer can be used if the hole has a larger diameter than the mounting nut.[2][3] Fender Washer (US), Penny Washer, Mudguard Washer or “Repair Washer” (UK) A flat washer with an extra large outside diameter in relation to its central hole. These are commonly used to spread the load on thin sheet metal and are named for their use on car fenders. They can also be used to connect to a hole enlarged by rust or wear. In Britain, the name originally came from the size of the old British penny. In the UK, most industries refer to all large OD washers as penny washers, even if the OD is twice the old penny. An archaic form of this washing machine was sold as a “pot flicker”, usually in small quantities through a hardware store. This included two washers, a nut and bolt, and a rubber, cork, or fiberboard gasket. They can be used to seal small holes, rust spots or removed pipe connections in water tanks or large cooking vessels. nut and bolt with spherical washer part of a self-aligning nut; It is a flat washer with a rounded surface designed to be used in conjunction with a mating nut to allow for up to several degrees of misalignment between parts. Anchor Plate or Shear A large plate or washer connected to a tie rod or bolt. Anchor plates are used on the exterior walls of masonry buildings for structural reinforcement. Since many anchor plates are visible, they are decorative.[5] Torque washer Used in woodworking in combination with a carriage bolt; It has a square hole in the center that fits the square of the carriage bolt. Teeth or prongs on the washer bite into the wood and prevent the bolt from turning freely when tightening a nut.[6]

Spring washers and lock washers[ edit ]

Name(s) Image Description Belleville washer, also known as Belleville washer or conical washer A slightly conical washer that generates an axial force when deformed. The surface may be serrated, which will have enhanced locking capabilities.[7] Curved Belleville Spring Similar to a Belleville spring, except the washer is only bent in one direction, so there are only four points of contact. In contrast to Belleville washers, they exert only light pressure.[8] Wave washers A washer with an axial “wave” that creates spring pressure when compressed. Comparable sized wave washers do not produce as much force as Belleville washers. In Germany they are sometimes used as lock washers, but are less effective than other alternatives.[a][9] Split washer or spring lock washer A ring that is split at one point and bent into a spiral shape. This causes the washer to exert a spring force between the fastener head and the substrate, forcing the washer hard against the substrate and the bolt threads hard against the nut or substrate threads, creating more friction and resistance to rotation. Applicable standards are ASME B18.21.1, DIN 127 B and the United States Military Standard NASM 35338 (formerly MS 35338 and AN-935).[10] Spring washers are a left-hand helix and only allow the thread to be tightened in the right-hand direction, i.e. clockwise. When a counter-clockwise rotation is performed, the raised edge bites into the underside of the bolt or nut and the part it is bolted to, resisting rotation. Therefore, spring washers are ineffective on left-hand threads and hardened surfaces [citation needed]. Also, they must not be used in conjunction with a flat washer under the spring washer as this will keep the spring washer from biting into the non-rotating component. The use and effectiveness of spring washers has been debated, with some publications[11][who?] advising against their use because when solid the washer lies flat on the substrate and offers no more resistance to rotation than a normal washer with the same torque . A 1990 NASA manual states: “In summary, a lockwasher of this type is useless for locking.” [7][12] However, a spring washer still holds the screw against the substrate and maintains friction when loosened slightly, while a smooth flat washer does not.[a] The advantage of spring washers is the trapezoidal shape of the washer. When compressed to loads close to the bolt’s yield strength, it twists and flattens. This reduces the spring rate of the bolted joint, allowing more force to be sustained for the same vibration levels. This prevents loosening.[13] Star Washer, Serrated Washer, or Star Washer[9] A washer with serrations that extend radially inward or outward to engage the bearing surface. This type of washer is particularly effective as a lock washer when used with a soft substrate such as aluminum or plastic,[9] and can resist rotation on hard surfaces more than a plain washer because of the tension applied between the washer and the surface is over a much smaller area (the teeth). There are four types: internal, external, combination and countersunk. The inner style has the prongs along the inside edge of the washer, making it more aesthetically pleasing.[14] The outer style has the prongs around the outer rim, which provides better holding power due to the larger circumference.[15] The combo style has serrations on both edges for maximum holding power.[16] The countersunk version is designed for use with countersunk screws.[17] Star washers are also used for grounding where a metal lug or object needs to be electrically connected to a surface. The washer’s teeth cut through surface oxide, paint or other coatings, creating a gas-tight conductive path. In these applications, the washer is not placed under the bolt head (or under the nut), but is placed between the surfaces to be bonded.[18] Lock Washer A lock washer that works by having a side tab that can be bent against a nut. Metallic or non-metallic, the lock washer notch prevents rotation relative to the shaft or fastener. Variations include single, multiple, shaped, and flat.[19] Wedge-Lock Washer A two-piece washer with radial teeth on one side and wedging the halves where they join. Although these washers are generally more expensive per piece, they offer the most protection from vibration loosening.[20]

Lock washers, lock nuts, lock nuts, and thread-locking fluid are means of preventing vibration from loosening a bolted joint.

seals [ edit ]

The term washer is often used for different types of gaskets, e.g. B. those used to seal the control valve in faucets.

Name Image Description Flanged Washer A type of washer with an integral cylindrical sleeve. Used as a barrier between dissimilar metals and as a seal.[21] This term is also used for electrically insulating grommets.[22] Crush washer A washer made of soft metal such as aluminum or copper. For sealing liquid or gas connections found in hydraulic systems and internal combustion engines.

Specialized Types[ edit ]

Name(s) Image Description Keps Nut or K-Lock Nut A nut with an integral free-spinning washer; Installation is easier because the washer cannot be lost. Self-Aligning Washer A two-piece washer: One piece has a convex spherical surface that mates with a concave surface on the other piece to allow tightening on a surface that is not perpendicular to the axis of the bolt or nut, similar to a spherical washer and a self-aligning mother. Insulating Washer Used to electrically insulate a fastener screw from the surface that secures it. These are often made of nylon, but also made of Teflon, PEEK or other plastics to withstand higher temperatures. Keyed Washer A washer with a key to prevent rotation and is used to secure two nuts in place without the torque applied to the top nut causing the bottom nut to rotate as well ( e.g. a threaded headset on a bicycle). Torque Limiting Washer A type of washer used in a variety of torque sensitive applications and designed to limit torque to a predetermined level and not beyond. Dowty Washer Features a central rubber ring to provide a strong seal against high pressure liquids or gases.

The DIN 125 metric washer standard refers to sub-types A and B. ISO 7089 calls this shape A and ISO 7090 calls it shape B. They are all the same overall size, but shape B is beveled on one side.

materials [edit]

Washers can be made from a variety of materials including but not limited to:[23]

Corrosion resistance[ edit ]

A number of techniques are used to improve the corrosion resistant properties of certain washer materials:

Metal Coatings – Typical coatings used to manufacture corrosion resistant washers are zinc, cadmium and nickel. The zinc coating acts as a sacrificial surface layer that will fall victim to corrosive materials before the washer material can be damaged. Cadmium creates a high quality protective surface but is both biologically and ecologically toxic. Nickel coatings only offer protection against corrosion if the surface is dense and non-porous.

Electroplating – In this process, the washer is coated with metals such as chrome or silver by electrolytic deposition.

Phosphating – A resistant but abrasive surface is achieved by incorporating a zinc phosphate layer and an anti-corrosion oil.

Blackening or Blueing – When the washer (usually steel) is exposed to a chemical compound or an alkaline salt solution, an oxidizing chemical reaction is initiated, resulting in the creation of a corrosion-resistant, colored surface. Coating integrity can be improved by treating the finished product with a water-displacing oil.

Chemical Plating – This technique uses a nickel-phosphorus alloy that is applied to the surface of the washer, creating an extremely corrosion and abrasion resistant surface.[26]

Type and shape[ edit ]

A flat washer and a spring washer are placed on a bolt between the nut (at the end of the thread) and the bolt head.

The American National Standards Institute (ANSI) provides standards for washers for general use. Type A is a range of steel washers with wide tolerances where precision is not critical. Type B is a series of tighter tolerance flat washers where the outside diameters are categorized as “narrow”, “regular” or “wide” for specific bolt sizes.[27]

“Type” is not to be confused with “shape” (but it often is). The British Standard for Metric Series Metal Washers (BS4320), written in 1968, coined the term “shape”. The shapes go from A to G and specify the outer diameter and thickness of the washers.

Shape A: Normal diameter, normal thickness

Form B: Normal diameter, small thickness

Form C: Large diameter, normal thickness

Form D: Large diameter, small thickness

Shape E: Normal diameter, normal thickness

Form F: Large diameter, normal thickness

Form G: Largest diameter, greater thickness.

The shape of the washer when comparing different types of washer materials is used fairly freely by specialty retailers. Specifically in relation to BS4320, washers of shapes ‘A’ to ‘D’ inclusive are referred to as ‘bare metal’ washers and are supplied hand finished in various metals including: alloy steels, brass, copper etc. Whereas BS4320 washers are ‘E’ ‘G’ through ‘G’ are designated as ‘black’ (uncoated) mild steel washers which are normally supplied with an additional protective coating.

Standard metric washer sizes[edit]

Standard metric size washers conforming to BS4320 Form A are listed in the table below. The dimensions in the table refer to the dimensions of the washers as described in the drawing. Specifications for standard metric flat washers were known as DIN 125 (withdrawn) and replaced by ISO 7089. DIN standards (Deutsches Institut für Normung – Deutsches Institut für Normung) are issued for a variety of components, including industrial fasteners as DIN 125 metric washers. The DIN standards remain widespread in Germany, Europe and worldwide, even if the transition to ISO standards takes place. DIN standards continue to be used for parts that have no ISO equivalents or for which there is no need for standardization.[28]

nominal screw

Sizes, M (mm) screw pitch

Thread, P (mm) Diameter (mm) Thickness,

H (mm) 1

choice 2

Choice Coarse Fine Internal

hole, d 1 outside,

D 2 1 0.25 1.1 3 0.3 1.2 0.25 1.3 3.5 0.3 1.4 0.3 1.5 4 0.3 1.6 0.35 1.7 4 0.3 1.7 1.8 4.5 0.3 1.8 0.35 2 0.4 2.2 5 0.3 0.3 0.5 2.7 6 0.5 2.8 7 0.5 3 0.5 3.2 7 0.5 0.6 0.7 3.7.7.7.7.7.7.7.7.7.7.37.7 0.7.7 ,7,7,7,7,7 0,5 2,8 7 0,5 3 0,5 3,5 0,5 3,5 0,6 3,7 3,7 3,7,7,7, 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7). 8 0.5 4 0.7 4.3 9 0.8 5 0.8 5.3 10 1 6 1 0.75 6.4 12 1.6 7 1 7.4 14 1.6 8 1.25 1 8.4 16 1.6 10 1.5 1.25 or 1 10.5 20 2 12 1.75 1.5 or 1.25 13 24 2.5 14 2 1.5 28 28 28 28 28 28 28 28 28 28 28 28 28 2.5 16 2 1.5 17 30 3 18 2.5 2 or 1.5 19 34 3 20 2.5 2 or 1.5 21 37 3 22 2.5 2 or 1.5 23 39 3 24 3 2 25 44 4 27 3 2 28 50 4 30 3.5 2 3.5 2 34 60 5 36 4 3 37 66 5 39 4 3 40 72 6 42 4.5 3 43 78 7 45 4.5 3 46 85 7 48 5 3 50 92 8 52 5 4 54 98 8 56 5.5 4 58 10 5 9 62 110 9 64 6 4 66 115 9 68 70 120 10 72 74 125 10 76 78 135 12 80 85 87 145 12 90 93 160 12 100 104 175 14

See also[edit]

Notes [edit]

a b [ citation needed ] Bowman’s Fastener Technical Fast of 1999 at pages 32 and 33 contains the 1969 SAE recommendation that lock washers should not be used in critical applications. A number of broken lock washers occurred on BMW motorcycles and BMW then refused to use them in U-joints due to the damage from losing the spacer and loosening the nut.

References[edit]

Further Reading[edit]

A new level of security for bolt security with the introduction of Nord-Lock’s X-Series washer, the company says. The X-Series combines the Nord-Lock company’s wedge-locking protection against spontaneous bolt loosening (due to vibration and dynamic loading) with an exclusive spring effect that protects against loosening due to settlement and relaxation. This combination makes the X-Series the first truly multifunctional design that offers the highest security for critical joints without compromise.

New technologies bring new requirements

With new technologies and requirements, joints are increasingly required to withstand loads from multiple fronts, including vibration, dynamic loading, settlement and relaxation. So far, however, no solutions have been developed on the market to secure screws from all of them at the same time. This has presented designers with the difficulty of identifying which problem – spontaneous loosening or bolt loosening – has the greatest impact on the joint and finding a solution to overcome that single problem. Nord-Lock says its X-Series ensures complete bolt security while simplifying construction and maintenance as there is no need to use and stock multiple solutions.

How it works

As with original Nord-Lock washers, each pair has lobes on one side and radial teeth on the opposite side to secure the bolted joint with tension rather than friction. The conical shape of the X-Series washers also creates an elastic reserve in the bolted joint to compensate for loss of preload and prevent loosening.

For a full video report on how X-Series washers add a new level of security to bolt security, visit www.nord-lock.com/x-series-video

North lock

www.nord-lock.com