Washers should be used to distribute the load of threaded fasteners, prevent looseness, and protect surfaces from damage.
Key Uses for Washers
Based on their design and function, washers play crucial roles in fastening applications. According to the reference provided:
Washers are used to distribute the load of a threaded fastener, such as a bolt or nut.
This means that when you tighten a bolt and nut, the washer spreads the pressure over a larger area. This is particularly important when fastening softer materials or when dealing with oversized holes.
Furthermore, the reference states:
Before a screw or bolt is driven into a surface, a washer may be placed in order to prevent looseness and provide protection.
Placing a washer under the head of a screw or bolt, or under a nut, helps create a smooth bearing surface, which can contribute to more consistent torque and clamping force. Some types of washers are specifically designed to resist loosening caused by vibration or expansion/contraction.
Finally, the reference highlights another key benefit:
This also prevents the bolt head and nut from damaging the surfaces of the two fastened parts.
Without a washer, the rotating bolt head or nut can dig into the material being fastened, potentially causing deformation or scratches. The washer acts as a sacrificial layer, protecting the underlying material.
Here's a summary of when washers are typically used:
- To Distribute Load: Essential for preventing damage to materials under the stress of a tightened fastener.
- To Prevent Looseness: Certain types (like lock washers) are specifically designed to add friction or mechanical interference to resist vibration.
- To Protect Surfaces: Shields the material from scoring or indentation caused by the fastener head or nut during tightening.
- To Provide a Smooth Bearing Surface: Helps achieve more accurate torque readings.
- As Spacers: Can be used to adjust the distance between components.
Practical Scenarios
Consider these common situations where washers are beneficial:
- Woodworking: Prevents bolts from sinking into wood surfaces.
- Metal Fabrication: Ensures even pressure distribution, especially on thin sheets.
- Automotive Repairs: Helps maintain tightness and prevents loosening from engine vibration.
- Plumbing: Often used with rubber washers to create watertight seals.
Common Washer Types and Uses
While the reference primarily describes the function of flat washers, it's helpful to know that different types exist for specific purposes:
| Washer Type | Primary Use | Benefit |
|---|---|---|
| Flat Washer | Load distribution, surface protection, spacing | Standard use, versatile |
| Lock Washer | Prevents loosening from vibration | Added security against unintentional unscrewing |
| Fender Washer | Distributes load over a very large area | Ideal for soft materials or large holes |
| Finishing Washer | Provides a clean, flush surface finish | Aesthetic appeal and load distribution |
Using the correct washer for the application is crucial for the longevity and integrity of the fastened joint. They are small components but play a significant role in ensuring the fastener performs as intended.
