Washers are essential components in mechanical assemblies, serving various purposes such as load distribution, spacing, and sealing. They come in numerous types, each designed to meet specific requirements in bolting applications. This article explores four common types of washers used with bolts and screws, detailing their unique characteristics and applications.
What is a Washer?
A washer is a small, round, flat disc with a hole in the middle, made from materials like brass, stainless steel, carbon steel, ceramics, phenolics, and plastics. Its primary function is to distribute the load of a threaded fastener over a larger area. Placed between a bolts and a screw, a washer acts as a spacer, reduces vibration from equipment or machinery, and prevents corrosion.
What are Washers For?
Washers serve to enhance the performance of threaded fasteners and protect surfaces from damage during tightening. They provide a larger bearing surface, preventing distortion of weaker materials. Even with identical materials, washers like lock washers can prevent loosening.
- Absorbs vibrations
- Provide interval protection for bolts and screws
- Prevents fastener movement
- Enhances application lifespan
- Distributes the load to prevent material damage
- Provide anti-corrosion and rust prevention protection
Commonly Used Materials for Washers
Washers are made from a variety of materials, each chosen based on specific application requirements such as load, environment, and compatibility. Here are the most commonly used materials for washers:
Nylon Washers
Nylon washers are lightweight and resistant to abrasion and chemicals. They find applications in industries where non-metallic, non-conductive materials are preferred, such as electronics and automotive.
Key Characteristics:
- Abrasion Resistance: Nylon washers withstand wear and tear, maintaining their integrity over time.
- Chemical Resistance: They resist degradation from various chemicals, ensuring long-term performance.
Rubber Washers
Rubber washers, made from various synthetic rubber compounds like nitrile or EPDM, are flexible and resilient. They excel in sealing applications where vibration damping and noise reduction are important, such as in automotive and machinery.
Key Characteristics:
- Flexibility: Rubber washers conform well to irregular surfaces, ensuring a tight seal.
- Vibration Damping: They reduce vibration and noise, enhancing equipment performance and longevity.
Metal Washers
Metal washers are available in various types and grades, each offering distinct advantages. Stainless steel washers are particularly prized for their corrosion resistance and ability to form strong seals, effectively preventing leaks and drips. Additionally, washers made from softer metals, such as copper, can reduce machine vibration, thereby enhancing connection safety.
Key Characteristics:
- Corrosion Resistance: Stainless steel washers are resistant to corrosion and provide reliable sealing.
- Vibration Dampening: Copper and other soft metal washers can help to minimize machine vibrations.
Here’s a table listing the physical characteristics of commonly used metals for washers:
| etal | Density (g/cm³) | Melting Point (°C) | Hardness (Mohs) | Electrical Conductivity (MS/m) | Thermal Conductivity (W/m·K) | Tensile Strength (MPa) | Young’s Modulus (GPa) |
|---|---|---|---|---|---|---|---|
| Stainless Steel | 7.8 | 1400-1450 | 3-4 | 1.4-1.8 | 15-45 | 500-2000 | 193-200 |
| Copper | 8.96 | 1084 | 2.5 | 58.0 | 401 | 210-350 | 110-130 |
| Aluminum | 2.7 | 660 | 2-2.9 | 37.7 | 237 | 70-700 | 69 |
| Brass | 8.4-8.73 | 900-940 | 3 | 15.0-28.0 | 109 | 340-520 | 100-125 |
| Bronze | 7.8-8.8 | 950-1030 | 3 | 6.7-14.0 | 60 | 240-550 | 110-125 |
| Titanium | 4.5 | 1668 | 6 | 5.7 | 21.9 | 240-1100 | 116 |
Plastic Washers
Plastic washers, typically produced via injection molding, offer a cost-effective alternative to metal washers. They are suitable for applications that do not demand high strength. Plastic washers are particularly advantageous for their electrical isolation properties and vibration resistance, making them ideal for use in electronics. These washers are available in a variety of colors and can also be found in clear versions.
Key Characteristics:
- Cost-Effectiveness: Plastic washers are generally more affordable than their metal counterparts.
- Electrical Isolation: They are excellent for applications requiring electrical isolation.
- Vibration Resistance: Plastic washers effectively reduce vibrations, making them suitable for sensitive applications.
Here’s a table listing the physical characteristics of commonly used plastic for washers:
| Plastic Type | Density (g/cm³) | Melting Point (°C) | Hardness (Shore D) | Flexural Strength (MPa) | Tensile Strength (MPa) | Young’s Modulus (GPa) | Thermal Conductivity (W/m·K) |
|---|---|---|---|---|---|---|---|
| Polyethylene (PE) | 0.91-0.97 | 115-135 | 50-70 | 10-35 | 10-20 | 0.1-1.0 | 0.35-0.51 |
| Polypropylene (PP) | 0.89-0.91 | 130-171 | 70-110 | 10-35 | 20-40 | 1.0-2.2 | 0.1-0.22 |
| Polyvinyl Chloride (PVC) | 1.3-1.45 | 75-100 | 75-85 | 40-60 | 45-60 | 1.4-2.8 | 0.14-0.22 |
| Polystyrene (PS) | 1.04-1.06 | 100-120 | 70-90 | 40-80 | 40-60 | 3.0-3.5 | 0.13-0.17 |
| Nylon | 1.12-1.15 | 220-260 | 70-120 | 40-80 | 50-80 | 2.0-4.0 | 0.25-0.3 |
| Polymethyl Methacrylate (PMMA) | 1.17-1.20 | 160-180 | 85-105 | 65-95 | 70-90 | 2.0-3.0 | 0.15-0.19 |
4 Different Types of Washers
Washers play crucial roles in various industries by distributing loads, preventing corrosion, and enhancing fastening efficiency. Here are four common types:
1. Plain Washers
Plain washers are fundamental components in various assembly applications, designed to distribute load and provide stability to fastened connections.
Flat Washer
Flat washers, also known as disc washers, feature a central hole and are ideal for distributing load in small screws. They prevent surface damage and ensure even pressure distribution. These washers are commonly used in woodworking and general assembly to provide stability and reduce wear on fastened surfaces.
Fender Washer
Fender washers have a larger outer diameter and a small central hole. Commonly used in automotive and plumbing industries, they spread loads over a broader area. This design helps prevent pull-through in thin materials and provides a larger bearing surface under the fastener head.
2. Spring Washers
Spring washers offer dynamic solutions for applications requiring flexibility and vibration resistance.
Belleville Washer
Conical in shape, Belleville washers maintain tension during thermal expansion. They are crucial for applications requiring high spring rates and minimal deflection. Belleville washers are used in bolted joints subjected to thermal cycling or where preload requirements are critical to joint integrity.
Wave Washer
Curved in two directions, wave washers act as cushions or spacers. They provide moderate load support and help mitigate surface wear. These washers are often used in assemblies where some flexibility is needed to compensate for tolerance variations or thermal expansion.
3. Lock Washers
Lock washers are essential for maintaining bolted joint integrity under mechanical stress and environmental conditions.
Split Lock Washer
Helical in shape, split lock washers prevent fasteners from loosening due to vibrations. They bite into the mating surface, enhancing grip and security. Split lock washers are commonly used in applications where maintaining preload on bolts and nuts is crucial, such as machinery and automotive assemblies.
External Tooth Lock Washer
Featuring external teeth, these washers resist loosening under torsional forces. They are effective with bolts that have larger heads, providing robust compression resistance. External tooth lock washers are ideal for applications where high vibration or dynamic loads may cause traditional fasteners to loosen over time.
Internal Tooth Lock Washer
Internal tooth lock washers have teeth on the inner diameter, securing shallow-head fasteners and reducing noise and vibration. They are commonly used in electrical equipment, appliances, and machinery where preventing loosening due to vibration is critical for operational reliability.
4. Specialized Washers
Specialized washers cater to specific industry needs, providing unique functionalities beyond standard applications.
Keps Nut
Also known as K-lock nuts, Keps nuts incorporate built-in washers for efficient assembly, particularly useful in industries requiring quick installations. These nuts are commonly used in electronics, automotive, and consumer goods industries to secure components without the need for additional washers.
Top Hat Washer
Top hat washers are commonly used in plumbing applications, especially for tap repairs, providing stability and leak prevention. Their unique shape allows them to fit securely around plumbing fixtures, ensuring a tight seal and preventing water leaks.
Insulating Shoulder Washer
Made from insulating materials like nylon or plastic, these washers isolate electrical currents, essential in electronics and electrical installations. Insulating shoulder washers prevent electrical shorts and ensure reliable performance in circuits and electronic devices.
At a Glance: Types and Uses of Washers
- Plain Washers: Distribute force and protect surfaces.
- Lock Washers: Prevent loosening under vibration.
- Spring Washers: Absorb vibrations and maintain tension.
- Specialized Washers: Serve unique functions in assembly and insulation.
How do You Choose the Right Lock Washer?
Choosing the right lock washer depends on specific application requirements and conditions. Split lock washers are typically used in standard bolt connections, providing additional fastening force due to their split design. External tooth lock washers use external teeth to prevent loosening of nuts or bolt heads, ideal for applications requiring high torsional resistance.
Which Washers are Best for Preventing Bolts or Nuts From Loosening?
Spring washers and lock washers are ideal for preventing loosening under vibration. Spring washers maintain tightness through elastic deformation, while lock washers like split lock washers and external tooth lock washers prevent loosening through their specific designs.
What Types of Washers are Suitable for Electronic or Electrical Equipment Installation?
Insulating shoulder washers are specifically designed for installation in electronic and electrical equipment. Made from insulating materials, they prevent direct contact between screws or nuts and conductive surfaces, minimizing the risk of electrical shorts or interference.
How Do You Choose Washers for Specific Engineering Projects?
Choosing the right washers depends on the project’s requirements. For instance, projects requiring maintenance of tightness under thermal expansion may necessitate the use of Belleville or conical washers.
Which Type of Washer is Suitable for Dispersing Load on Small Screws?
For applications where weight needs to be dispersed on small screws, flat washers are ideal. They are typically disc-shaped with a central hole, effectively distributing the pressure of the screw head and preventing damage to the surface during assembly.
Should I Use a Washer Or a Spacers?
Washers and spacers serve similar functions but differ in design and application specifics. Washers are typically thinner and designed to distribute load, prevent wear, and manage friction between surfaces. On the other hand, spacers are often thicker and used to precisely position components, providing clearance or alignment.
Key Differences:
| Feature | Washers | Spacers |
|---|---|---|
| Thickness | Typically thinner | Generally thicker |
| Design Purpose | Distribute load, prevent loosening, temporary | Create precise gaps or distances, permanent |
| Primary Function | Load distribution, friction management, temporary spacers | Consistent separation, long-term support |
| Application | Quick adjustments, temporary use until proper spacer installed | Long-term precise spacing in mechanical assemblies |
Choosing Between Washers and Spacers
- Temporary vs. Permanent: Washers can serve as immediate solutions in machines until replaced by spacers for more permanent positioning.
- Friction Management: Washers mitigate friction that can hinder movement, whereas spacers provide stable and exact spacing between components.
Whether to use a washer or a spacer depends on the application’s requirements for load distribution, alignment, and long-term stability. Washers can function as temporary spacers, but for precise and permanent spacing needs, spacers are the optimal choice.
How to Apply Washers to Bolts and Screws?
Washers play a crucial role in securing bolts and screws, providing stability, preventing damage, and improving joint strength. Here’s how to correctly apply washers depending on your assembly scenario:
Taking spring washers and locking washers as examples
1. Spring Washers:
- Placement: Spring washers should always be placed on the nut side of the assembly. They help maintain tension and prevent loosening due to vibrations.
2. Lock Washers:
- General Rule: For applications using lock washers, place the washer on the side that will turn and drive into the surface during tightening. This is typically the nut side unless specified otherwise.
- Specific Scenarios:
- To Prevent Loosening: Place the lock washer on the side that will turn (usually the nut side).
- Threaded Bolt: If the bolt is threading into any part of the assembly, place the lock washer on the bolt side.
- Protecting Surface: Place the washer on the side that will press against the surface during tightening to prevent damage.
- Thin Material: Use a larger washer to distribute load and pressure more effectively, placing it against the material.
3. Order of Washers:
- Lock Washer and Flat Washer: If there’s a risk of the washer mushrooming during tightening, use a flat washer with a smaller diameter first, followed by the larger lock washer.
Tips for Effective Use:
- Material Compatibility: Consider the material of both the washer and the fastener to ensure compatibility and prevent corrosion.
- Multiple Washers: When necessary, use multiple washers to achieve the desired spacing or load distribution.
Size Chart of Different Types of Washers
Flat Washer Sizes
Flat washers are essential components used to distribute load, prevent damage to surfaces, and ensure secure fastening in various applications. They are standardized by two main systems: SAE (Society of Automotive Engineers) and USS (United States Standards). Here’s a detailed size chart for SAE and USS flat washers:
SAE Flat Washers
| Size(in.) | Inside Diameter (in. / mm) | Outside Diameter (in. / mm) | Thickness (in. / mm) |
|---|---|---|---|
| #6 | 5/32 (4 mm) | 3/8 (10 mm) | 3/64 (1.2 mm) |
| #8 | 3/16 (5 mm) | 7/16 (11 mm) | 3/64 (1.2 mm) |
| #10 | 7/32 (6 mm) | 1/2 (13 mm) | 3/64 (1.2 mm) |
| 1/4 | 9/32 (7 mm) | 5/8 (16 mm) | 1/16 (1.6 mm) |
| 5/16 | 11/32 (9 mm) | 11/16 (18 mm) | 1/16 (1.6 mm) |
| 3/8 | 13/32 (10 mm) | 13/16 (21 mm) | 1/16 (1.6 mm) |
| 7/16 | 15/32 (12 mm) | 59/64 (24 mm) | 1/16 (1.6 mm) |
| 1/2 | 17/32 (14 mm) | 1-1/16 (27 mm) | 3/32 (2.4 mm) |
| 9/16 | 19/32 (15 mm) | 1-3/16 (30 mm) | 3/32 (2.4 mm) |
| 5/8 | 21/32 (17 mm) | 1-5/16 (33 mm) | 3/32 (2.4 mm) |
| 3/4 | 13/16 (21 mm) | 1-1/2 (38 mm) | 9/64 (3.6 mm) |
| 7/8 | 15/16 (24 mm) | 1-3/4 (44 mm) | 9/64 (3.6 mm) |
| 1 | 1-1/16 (27 mm) | 2 (51 mm) | 9/64 (3.6 mm) |
| 1-1/8 | 1-3/16 (30 mm) | 2-1/4 (57 mm) | 9/64 (3.6 mm) |
| 1-1/4 | 1-5/16 (33 mm) | 2-1/2 (64 mm) | 9/64 (3.6 mm) |
| 1-3/8 | 1-7/16 (37 mm) | 2-3/4 (70 mm) | 5/32 (4 mm) |
| 1-1/2 | 1-9/16 (40 mm) | 3 (76 mm) | 5/32 (4 mm) |
USS Flat Washers
| Size (in.) | Inside Diameter (in. / mm) | Outside Diameter (in. / mm) | Thickness (in. / mm) |
|---|---|---|---|
| 3/16 | 1/4 (6 mm) | 9/16 (14 mm) | 3/64 (1.2 mm) |
| 1/4 | 5/16 (8 mm) | 3/4 (19 mm) | 1/16 (1.6 mm) |
| 5/16 | 3/8 (10 mm) | 7/8 (22 mm) | 5/64 (2 mm) |
| 3/8 | 7/16 (11 mm) | 1 (25 mm) | 5/64 (2 mm) |
| 7/16 | 1/2 (13 mm) | 1-1/4 (32 mm) | 5/64 (2 mm) |
| 1/2 | 9/16 (14 mm) | 1-3/8 (35 mm) | 7/64 (2.8 mm) |
| 9/16 | 5/8 (16 mm) | 1-1/2 (38 mm) | 7/64 (2.8 mm) |
| 5/8 | 11/16 (18 mm) | 1-3/4 (44 mm) | 9/64 (3.6 mm) |
| 3/4 | 13/16 (21 mm) | 2 (51 mm) | 5/32 (4 mm) |
| 7/8 | 15/16 (24 mm) | 2-1/4 (57 mm) | 11/64 (4.4 mm) |
| 1 | 1-1/16 (27 mm) | 2-1/2 (64 mm) | 11/64 (4.4 mm) |
| 1-1/8 | 1-1/4 (32 mm) | 2-3/4 (70 mm) | 11/64 (4.4 mm) |
| 1-1/4 | 1-3/8 (35 mm) | 3 (76 mm) | 11/64 (4.4 mm) |
| 1-3/8 | 1-1/2 (38 mm) | 3-1/4 (83 mm) | 3/16 (4.8 mm) |
| 1-1/2 | 1-5/8 (41 mm) | 3-1/2 (89 mm) | 3/16 (4.8 mm) |
| 1-5/8 | 1-3/4 (44 mm) | 3-3/4 (95 mm) | 3/16 (4.8 mm) |
| 1-3/4 | 1-7/8 (48 mm) | 4 (102 mm) | 3/16 (4.8 mm) |
| 1-7/8 | 2 (51 mm) | 4-1/4 (108 mm) | 3/16 (4.8 mm) |
| 2 | 2-1/8 (54 mm) | 4-1/2 (114 mm) | 3/16 (4.8 mm) |
| 2-1/2 | 2-5/8 (67 mm) | 5 (127 mm) | 15/64 (6 mm) |
| 3 | 3-1/8 (79 mm) | 5-1/2 (140 mm) | 9/32 (7 mm) |
Spring Washers Sizes
Spring washers are designed to provide a locking action to prevent loosening under vibration and torque. They come in various types tailored to specific application needs.
Split Spring Washers
| Size (#) | Inside Diameter (in. / mm) | Outside Diameter (in. / mm) | Thickness (in. / mm) |
|---|---|---|---|
| #2 | 3/32 (2.4 mm) | 5/16 (7.9 mm) | 1/64 (0.4 mm) |
| #4 | 1/8 (3.2 mm) | 3/8 (9.5 mm) | 1/64 (0.4 mm) |
| #6 | 5/32 (4.0 mm) | 7/16 (11.1 mm) | 1/64 (0.4 mm) |
| #8 | 3/16 (4.8 mm) | 1/2 (12.7 mm) | 3/128 (0.8 mm) |
| #10 | 7/32 (5.6 mm) | 9/16 (14.3 mm) | 3/128 (0.8 mm) |
| 1/4 | 9/32 (7.1 mm) | 5/8 (15.9 mm) | 1/16 (1.6 mm) |
| 5/16 | 11/32 (8.7 mm) | 3/4 (19.1 mm) | 1/16 (1.6 mm) |
| 3/8 | 13/32 (10.3 mm) | 7/8 (22.2 mm) | 1/16 (1.6 mm) |
| 7/16 | 15/32 (11.9 mm) | 1 (25.4 mm) | 5/64 (2.0 mm) |
| 1/2 | 17/32 (13.5 mm) | 1-1/8 (28.6 mm) | 5/64 (2.0 mm) |
Conical (Belleville) Washers
| Size (in. / mm) | Inside Diameter (in. / mm) | Outside Diameter (in. / mm) | Thickness (in. / mm) |
|---|---|---|---|
| 1/4 (6.4 mm) | 5/16 (7.9 mm) | 5/8 (15.9 mm) | 0.032 (0.8 mm) |
| 5/16 (7.9 mm) | 3/8 (9.5 mm) | 3/4 (19.1 mm) | 0.039 (1.0 mm) |
| 3/8 (9.5 mm) | 7/16 (11.1 mm) | 7/8 (22.2 mm) | 0.047 (1.2 mm) |
| 7/16 (11.1 mm) | 1/2 (12.7 mm) | 1 (25.4 mm) | 0.055 (1.4 mm) |
| 1/2 (12.7 mm) | 9/16 (14.3 mm) | 1-1/8 (28.6 mm) | 0.063 (1.6 mm) |
| 5/8 (15.9 mm) | 11/16 (17.5 mm) | 1-3/8 (34.9 mm) | 0.079 (2.0 mm) |
| 3/4 (19.1 mm) | 13/16 (20.6 mm) | 1-5/8 (41.3 mm) | 0.094 (2.4 mm) |
Wave Washers
| Size (mm) | Inside Diameter (mm) | Outside Diameter (mm) | Thickness (mm) |
|---|---|---|---|
| 3 | 3.2 | 6.4 | 0.4 |
| 4 | 4.3 | 8.2 | 0.5 |
| 5 | 5.3 | 10.5 | 0.6 |
| 6 | 6.4 | 12.7 | 0.7 |
| 8 | 8.4 | 16.8 | 0.9 |
| 10 | 10.5 | 21.0 | 1.0 |
Lock Washers Sizes
Lock washers are used to prevent nuts and bolts from loosening under vibration or torque. They include various types suitable for different applications.
Split Lock Washers
| Size (#) | Inside Diameter (in. / mm) | Outside Diameter (in. / mm) | Thickness (in. / mm) |
|---|---|---|---|
| #2 | 3/32 (2.4 mm) | 5/16 (7.9 mm) | 1/64 (0.4 mm) |
| #4 | 1/8 (3.2 mm) | 3/8 (9.5 mm) | 1/64 (0.4 mm) |
| #6 | 5/32 (4.0 mm) | 7/16 (11.1 mm) | 1/64 (0.4 mm) |
| #8 | 3/16 (4.8 mm) | 1/2 (12.7 mm) | 3/128 (0.8 mm) |
| #10 | 7/32 (5.6 mm) | 9/16 (14.3 mm) | 3/128 (0.8 mm) |
| 1/4 | 9/32 (7.1 mm) | 5/8 (15.9 mm) | 1/16 (1.6 mm) |
| 5/16 | 11/32 (8.7 mm) | 3/4 (19.1 mm) | 1/16 (1.6 mm) |
| 3/8 | 13/32 (10.3 mm) | 7/8 (22.2 mm) | 1/16 (1.6 mm) |
| 7/16 | 15/32 (11.9 mm) | 1 (25.4 mm) | 5/64 (2.0 mm) |
| 1/2 | 17/32 (13.5 mm) | 1-1/8 (28.6 mm) | 5/64 (2.0 mm) |
External Tooth Lock Washers
| Size (in. / mm) | Inside Diameter (in. / mm) | Outside Diameter (in. / mm) | Thickness (in. / mm) |
|---|---|---|---|
| #4 | 1/8 (3.2 mm) | 5/16 (7.9 mm) | 1/32 (0.8 mm) |
| #6 | 5/32 (4.0 mm) | 3/8 (9.5 mm) | 1/32 (0.8 mm) |
| #8 | 3/16 (4.8 mm) | 7/16 (11.1 mm) | 1/32 (0.8 mm) |
| #10 | 7/32 (5.6 mm) | 1/2 (12.7 mm) | 1/16 (1.6 mm) |
| 1/4 | 9/32 (7.1 mm) | 5/8 (15.9 mm) | 1/16 (1.6 mm) |
| 5/16 | 11/32 (8.7 mm) | 3/4 (19.1 mm) | 1/16 (1.6 mm) |
| 3/8 | 13/32 (10.3 mm) | 7/8 (22.2 mm) | 1/16 (1.6 mm) |
| 7/16 | 15/32 (11.9 mm) | 1 (25.4 mm) | 5/64 (2.0 mm) |
| 1/2 | 17/32 (13.5 mm) | 1-1/8 (28.6 mm) | 5/64 (2.0 mm) |
Specialized Washers Sizes
Specialized washers serve specific purposes beyond general fastening, tailored to unique application needs.
Insulating Shoulder Washers
| Size (mm) | Inside Diameter (mm) | Outside Diameter (mm) | Thickness (mm) |
|---|---|---|---|
| M3 | 3.2 | 6.4 | 1.0 |
| M4 | 4.3 | 8.2 | 1.0 |
| M5 | 5.3 | 10.5 | 1.5 |
| M6 | 6.4 | 12.7 | 1.5 |
| M8 | 8.4 | 16.8 | 2.0 |
Gaskets
Gaskets are used to create a seal between two surfaces, preventing leaks and ensuring proper fluid or gas containment.
| Size (in. / mm) | Inside Diameter (in. / mm) | Outside Diameter (in. / mm) | Thickness (in. / mm) |
|---|---|---|---|
| 1/2 (12.7 mm) | 1/2 (12.7 mm) | 1 (25.4 mm) | 1/16 (1.6 mm) |
| 3/4 (19.1 mm) | 3/4 (19.1 mm) | 1-1/4 (31.8 mm) | 1/16 (1.6 mm) |
| 1 (25.4 mm) | 1 (25.4 mm) | 1-1/2 (38.1 mm) | 1/8 (3.2 mm) |
| 2 (50.8 mm) | 2 (50.8 mm) | 2-1/2 (63.5 mm) | 3/16 (4.8 mm) |
Note: The sizes listed above are standard dimensions and may vary based on manufacturer specifications and specific application requirements. Always select washers that match the bolt and nut sizes for optimal performance and safety in your applications.
What are the Forms of Washers?
Different forms of washers serve specific functions across various industries, from correcting angular misalignments and distributing torque to providing electrical insulation, vibration absorption, and component retention.
| Image Example | Washer Shape | Description | Typical Examples | Applications |
|---|---|---|---|---|
 | Spherical Shape | Features precise parallel planes between bolt head and nut face, corrects angular misalignments. | Fender, slotted, countersunk, flat washers | Automotive, construction, machinery |
 | Square Shape | Offers larger surface area for improved torque distribution, resists rotation, aids in electrical insulation. | Flat, structural, countersunk washers | Seismic applications, electrical insulation |
 | Shoulder Shape | Non-metallic washers, often nylon, with long or short barrels, protect fasteners from moisture and dirt. | Insulator washers | Electrical and electronic applications |
 | Wave Shape | Curved in two directions, acts as spacers or cushions, sustains loads, absorbs vibrations. | Wave washers | Automotive, aerospace, industrial equipment |
 | C-Shaped | Slides on and off bolts without loosening, retains components on grooved shafts. | Lock, slotted washers | Mechanical and automotive assemblies |
Conclusion
Choosing the right type of washer is crucial for the success of any fastening application. By understanding the characteristics and advantages of each type of washer , it can be ensured that the most suitable washer is selected during installation and maintenance to ensure safe and reliable assembly results.
BOYI provides customized machining services for your washer. Welcome to contact us for a free quote.
Let’s Start A New Project Today
Our engineers will contact you within 2 hours.
FAQ
Lock washers, such as split lock washers and external tooth lock washers, prevent bolts or nuts from loosening under vibration. Their design increases clamping force, providing additional friction or resistance to maintain stability.
Specialized washers include insulating shoulder washers, wave washers, and top hat washers. For instance, insulating shoulder washers are common in electronics for isolating metal components and reducing electrical conductivity, while wave washers are used to mitigate vibrations and compensate for surface irregularities. Top hat washers are often employed in plumbing to prevent leaks during pipe and faucet installations.
External tooth lock washers feature teeth on the outer diameter to prevent nuts or bolt heads from loosening, providing high torque resistance. In contrast, internal tooth lock washers have teeth on the inner diameter, suitable for applications requiring reduced axial space and minimizing contact area with bolt heads.
Several key washer standards include ASME ANSI B18.22.1 for plain washers, ASTM F844 for flat washers in the inch series, ASME B18.21.1 for helical spring-lock washers, DIN 125A for flat washers made from sheet metal, and DIN 6799 for retaining washers, also known as E-Rings.
Catalog: Blog
This article was written by engineers from the BOYI team. Fuquan Chen is a professional engineer and technical expert with 20 years of experience in rapid prototyping, mold manufacturing, and plastic injection molding.
