Its shape is like a round ring. Before tightening the nut and bolt, it is fitted on a stud or bolt. It is used to secure the tightness of a joint, screw, etc. and it becomes easy to open the nut-bolts and their threads are protected.
Even if the fit is a bit larger than the diameter of the bolt, with the washers help nut bolt can be tightened easily.
Also, check out the different types of nuts and bolts used in industries. You may like to know about types of threads in the designing of nuts and bolts. Furthermore, check out different types of screwdrivers for tightening and loosening and screws.
Types of Washers
Following are the types of washers, as per their utility and functions:
- Spring washer
- Belleville or conical washer
- Dome spring washer
- Wave spring washer
- Finger spring washer
- Crescent spring washer
- Lock washer
- Split lock washer
- External tooth lock washer
- Internal tooth lock washer
- Torque Washer
- Plain washer
- Torque washer
- Flat washer
- Fender washer
- Finishing or Countersunk washer
- Shoulder washer
- C-washer
- Specialized washers
- Keps Nut.
- Top Hat Washers.
- Keyed Washers.
- Insulating Washers.
- Gaskets.
- Retaining Push Nuts.
- Spherical Washer.
- Structural Washers.
#1. Spring Washer.
This spring steel washer is in the shape of a ring that has been cut out. Its ends are slightly raised up and down because of spring tension. These washers are placed above or below the nut or bolt and tighten so much that both of their ends face each other and become level.
These washers are used to prevent a nut from becoming loose. This is used where there is vibration, or jolts occur. This applies pressure against the nut to prevent it from turning and becoming loose.
There are several forms of spring washers. Each has its own advantages.
There is the single pattern spring washer, standard pattern spring washer, double pattern spring washer, grip pattern spring washer and girder pattern spring washer. These are the structures of spring washer.
#1. Belleville or Conical Washer.
The Belleville washer consists of sides that kink under heavyweight force without changes in length. It is also called a conical spring washer.
These washers hold an assembly under tension for thermal expansion or contraction requirements. The conical washer load-deflection characteristics depend on its height and thickness ratio. It is used for incidents in thermal expansion.
#2. Dome Spring Washer.
The dome spring washer is very similar to a Belleville washer, with a rounded side. Dome spring washers yield very high load capabilities with a relatively small load-deflection range.
They have ground curves so that a flatter load-bearing surface is formed. It is used wherever you would use a crescent spring washer, and there is also a need to have a flat surface.
#3. Wave Spring Washer.
These washers rotate in two different directions, taking on a wave-like form. Wave spring washers have enough load capacity and deflection available.
The washers are used as cushion springs or spacers on a shaft. Wave washers are average load capacity and deflections. It is most frequently used as a cushion or spacer.
#4. Finger Spring Washer.
Finger spring washers have three curved flanges. Finger spring washers are used for the purpose of reducing the damper and noise, representing less wear, vibration, and skidding wear of revolving parts.
Finger spring washers are made of carbon steel. They take the flexible load of a casing washer, with the given point of load, for creating the planned load point of a wave washer.
#5. Crescent Spring Washer.
Crescent spring washers look like flat washers that are somewhat bent to provide lighter pressure while still being flexible in shape. It is also known as a curved spring washer. They provide almost small loads, with a much wider range of deflection.
Crescent spring washers have even uniform spring rates delivered over the deflection range, and they have linear load and deflection. They are to be used in flexible and load-cycling goods; they are also used to absorb movement.
#2. Lock Washer.
This type of lock washer prevents nuts and bolts from loosening. There are many kinds, with six or more leaves extending past the outer diameter.
After you apply this washer, its leaves are bent against the sides of the nut or bolt, effectively locking it in to prevent loosening. It is used primarily with automobiles.
#1. Split Lock Washer
A split lock washer is a non-continuous ring washer with its ends bent slightly outward from each other in opposite directions. When you apply a split lock washer it digs in on the ends into the surfaces it is being fastened. This type of washer sometimes is called a helical washer.
A split lock washer develops preload on the screw when you tighten the screw. The preload does provide security against loosening during vibration and corrosion. A split lock washer typically will also hold a bolt in place.
#2. External Tooth Washer
This type of lock washer has many teeth on the outer diameter that cut into a surface while keeping a good compression force in the assembly. An external tooth washer will help keep a fastener head from loosening by utilizing the strut action of the teeth on the washer.
An external toe washer will work best with larger heads screws and give maximum resistance to torsion forces. External tooth washers are used to lock bolts with deep heads in place.
#3. Internal Tooth Washer
An internal tooth washer is similar to an external tooth washer, except the teeth are on the inner diameter of the washer, and when you apply an internal tooth washer it digs into the threaded part of the bolt or nut to help retain the squeezing action.
The teeth on an internal tooth washer will help absorb a shock or appreciable amount of vibration while keeping the nut or bolt tight by again using the strut action of the washers teeth. Internal tooth washers are mostly used with shallow-headed fasteners.
#4. Torque Washer
A torque washer, or a wedge lock washer, has four prongs that dig into the materials you are fastening it to, and effectively locks the bolt into place, and prevents from loosening over time. Torque washers are used a lot in woodworking.
#3. Plain Washer.
A plain washer is just a flat disk with a hole through the center that a bolt, stud, or set-screw can go through.
It levels the surface of the material under the bolt or nut (providing a flat surface) to equally distribute the pressure of the nut against the surface. The standard for a plain washer is as follows:
Diameter of inner hole = Diameter of bolt
Diameter of the washer = 2D + 1/8 (D = Diameter of bolts)
Thickness of Washer = 1/8 D
Chamfer Angle = 30°
#1. Torque Washer.
The Torque washer features a square hole and outer forks to limit the bolt from turning with it when fastening a bolt. It is primarily used with a carriage bolt in woodworking applications.
#2. Flat Washer.
The flat plain washers are flat, thin, and circular shaped with a hole in the middle. The application of flat plain washers is to give the load over a relatively large area and to support small head screws.
They are also known as Type A plain washers. The flat washer is what most people think of when they think of a normal washer. They are good for general use.
#3. Fender Washer.
The fender washers are flat washers with a small hole and outside relatively large diameter. Therefore, this type of plain washer distributes loads over a relatively much larger area than flat washers.
Fender washers are used for installing signboards, electrical applications, plumbing, sheet metal, drywall, and on automobiles. Typically, they are thin metal. They have called this a fender washer because of their general use on automobile fenders.
#4. Finishing or Countersunk Washer.
The finishing washer has a top designed to hold the fastener. It is also referred to as a countersunk washer. The Countersunk washer has a 90° or 120° counter at the top of the washer.
These washers serve as the flat washer for flat head countersunk screws. This gives a flush surface to the countersunk screw.
#5. Shoulder Washer.
Shoulder washers consist of a shoulder type structure. They are used to protect screws, wires, or any unit in the assembly from the rest of the assembly. They are available in fiber-glass, phenolic, nylon, PCTFE, PTFE, and metals.
#6. C-Washer.
These look like a flat washer; however, it has a slot cut from the center hole to from a “C” shape. A C-washer is made to slide in and out of place on the bolt or shaft.
The C-Washer used at any time may need to be adjusted or replaced, without removing the fastener.
#4. Specialized washers.
There are 8 Types of Special Washers:
#1. Keps Nut.
The Keps nut (or a K-lock nut) is designed in a nut shape with a lock washer connected to its center.
The purpose of the lock washer is to hold the lock washer in place when exposed to vibration and disturbance.
#2. Top Hat Washers.
Top hat washers have the look of a “top hat” (a flat top and a larger base) – often referred to as flanged washers.
The type of surface area provides load distributing capabilities and allows for use on softer or thinner materials to avoid damage to surface material through surface crushing/indentation.
#3. Keyed Washers.
Keyed washers are a type or style of washer that is slotted or keyed to fit into a corresponding keyway designed on a corresponding shaft.
The purpose is so that the washer does not move or turn during operation. Keyed washers are used in a variety of rotational parts, such as gears, motors and pulleys.
#4. Insulating Washers.
Insulating washers are also referred to as shoulder washers or insulating bushings. The shoulder part refers to a cylindrical raised area protruding, or raised, from the flat washer.
The shoulder adds space between the fastener and the base material. An additional purpose is to provide insulation for the fastener to the base material.
#5. Gaskets.
Gaskets are primarily either circular or rectangular in shape. The purpose of a gasket is to seal the joint between two objects or surfaces and prevent leakage of fluid or gas.
A gasket will typically be designed more complexly, often times out of more flexible material so that the gasket can conform to the surface between the two sealed components.
#6. Retaining Push Nuts.
Retaining push nuts, or push-on retainers, or push-on nuts, are another example of a fastener. The purpose of the retaining push nut is to quickly yet treaded retain components over a shaft or a stud. Retaining push nuts will typically be composed or made with a spring steel material.
To secure, the internal part of the nut will have teeth or serration when placed over the shaft or stud; this creates a resistant or tapered grip to aid in restricting loosening.
#7. Spherical Washer.
A spherical washer is another example of a specialty or unusual washer, it will feature one side that is concave spherical cap, and the other side is flat.
The spherical cap permits rotational adjustment but does keep consistent necessary contact and allows for a more even load when components are not perfectly aligned.
#8. Structural Washers.
Structural washers, also referred to as load-indicating washers, or high-strength washers, will be very thick, or heavy-duty, and will be used with high-strength fasteners. They will be slightly conical, or even a small bevel on one side, structural washers are used to help with construction of buildings, bridges, and even industrial structures using steel.
Conclusion
The washer is a disc-shaped flat plate with a hole in the center and is used to give loads over a large area and is used for spacers, pre-loading screws, springs, and vibration reduction.
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