Washers
What Are Washers?
Washers are mechanical components used alongside bolts, nuts, and screws to improve the performance, safety, and reliability of a joint. They are usually thin, flat discs with a hole in the centre.
In A Level Product Design, washers are important because they: - Improve joint strength - Protect materials - Prevent loosening - Increase safety and durability
How Washers Work
A washer works by: 1. Sitting between the nut or bolt head and the surface of the material 2. Spreading the clamping force over a larger area 3. Reducing pressure on the material 4. Improving friction and stability
This helps prevent damage and joint failure.
Main Functions of Washers
Washers are used to: - Spread load - Prevent surface damage - Reduce loosening - Improve joint reliability - Compensate for oversized holes - Improve appearance (in some cases)
Common Types of Washers
Plain Washer
- Flat, circular washer
- Most common type
Purpose: - Spreads load - Protects material surface
Used for: - General fixing - Wood, metal, and plastic joints
Spring Washer
- Split or coiled washer
Purpose: - Applies tension - Prevents loosening due to vibration
Used for: - Machinery - Moving parts - Automotive products
Penny Washer
- Large‑diameter washer with small central hole
Purpose: - Spreads load over a very large area
Used for: - Soft materials (wood, plastics) - Thin sheet materials
Star (Shakeproof) Washer
- External or internal teeth
Purpose: - Bites into surfaces - Prevents rotation and loosening
Used for: - Electrical components - High‑vibration environments
Nylon / Plastic Washer
- Made from plastic or nylon
Purpose: - Electrical insulation - Prevents scratching - Corrosion resistance
Used for: - Electronics - Decorative products
Sealing Washer
- Includes rubber or neoprene insert
Purpose: - Creates a watertight seal
Used for: - Outdoor products - Plumbing - Weatherproof assemblies
Materials Used to Make Washers
Washers are commonly made from: - Steel - Stainless steel - Brass - Aluminium - Nylon / plastic - Rubber (sealing washers)
Material choice affects: - Strength - Corrosion resistance - Cost - Electrical insulation
Advantages of Using Washers
- Improve joint strength
- Protect surfaces from damage
- Reduce loosening
- Increase joint lifespan
- Low cost
- Easy to use
- Improve safety
Disadvantages of Using Washers
- Additional components increase assembly time
- Small parts can be lost
- Incorrect washer choice can reduce effectiveness
- Slight increase in cost and weight
Washers vs No Washers
| Feature | With Washer | Without Washer |
|---|---|---|
| Load distribution | ✅ Good | ❌ Poor |
| Surface protection | ✅ Yes | ❌ No |
| Loosening risk | ✅ Reduced | ❌ Higher |
| Joint reliability | ✅ High | ❌ Lower |
Washers significantly improve joint performance.
Typical Uses in Product Design
Washers are used for: - Furniture assembly - Flat‑pack products - Machinery - Automotive parts - Electrical products - Outdoor structures - Prototypes - Engineering assemblies
They are used in almost all bolted joints.
Health and Safety Considerations
- Use correct washer size
- Ensure washer sits flat
- Do not stack washers incorrectly
- Check for sharp edges
- Secure joint properly before use
Incorrect washer use can cause joint failure.
Sustainability Considerations
Advantages
- Extend product lifespan
- Allow disassembly and repair
- Support Design for Disassembly (DfD)
- Reusable components
Disadvantages
- Metal production is energy‑intensive
- Small parts may be lost
Washers contribute to repairable and sustainable design.
Suitability for A Level Product Design
Washers are suitable when: - Load needs to be spread - Soft materials are used - Vibration is present - Joint reliability is important - Products require maintenance or repair
They are less suitable when: - Space is very limited - Alternative locking methods are used - One‑off decorative joints are required
Exam Tips (A Level)
- Define washers clearly
- State their purpose (spread load, prevent damage)
- Name specific types (plain, spring, penny)
- Link washer choice to material
- Compare with joints without washers
- Mention vibration and safety
- Use examples (e.g. furniture, machinery)
Key Keywords
- Washer
- Plain washer
- Spring washer
- Penny washer
- Load distribution
- Mechanical fixing
- Vibration resistance
- Design for Disassembly
Overall Summary
Washers are simple but essential mechanical components used with screws, bolts, and nuts to improve joint performance, safety, and durability. By spreading load, protecting materials, and reducing loosening—especially under vibration—washers significantly increase the reliability of mechanical joints. Available in many forms such as plain washers, spring washers, penny washers, and locking washers, they are widely used in furniture, engineering, automotive, and product design. In A Level Product Design, washers should be evaluated in terms of their function, material choice, joint reliability, sustainability, and contribution to safe, repairable products.