FASTENERS 101™

Washer FAQ

Frequently Asked Questions (FAQ) About Washers

Washers FAQs

Quick answers to common questions about washers.

Will zinc washers rust?

Zinc washers may rust in harsh (or marine) environments or if marring occurs.

What are washers?

Washers are thin round spacers that are usually fitted on the end of a bolt before a nut to provide a smooth even surface for the nut to tighten against.

What determines the size of a washer?

A washer's size is determined by the inner diameter of the washer.

Will galvanized washers rust?

Galvanized washers will rust in very harsh environments but are considered to be one of the more corrosive resistant finishes available.

What is a lock washer?

A lock washer is a washer that adds extra tension to an assembly to make it less likely to loosen by accident or vibration.

Can washers rust?

Washers can rust, always use washers in a material appropriate to your environment to deter rust.

Can lock washers get reused?

Some lock washers can be reused. Internal and external tooth lock washers cannot typically get reused as they have teeth that get bent when installed. Split ring lock washers can be reused.

Where are washers used?

Washers are used on a bolt, between the installation material and the nut to provide a smooth even surface area for the nut to tighten against. They also help distribute pressure over a wider area.

Are washers important?

Washers are important. They ensure that a nut is installed properly and prevent softer materials from damage by distributing the pressure over a greater surface area.

Are washers necessary?

Washers are not always necessary but it is common practice to use them anyway.

How do spring washers work?

Spring washers add tension to a fastener assembly and are used to absorb a shock or vibrations.

How many washers per bolt?

Typically, only one washer is used on the nut side of a bolt and nut assembly but more can be used depending on the application.

How do lock washers work?

Lock washers have some characteristic that adds tension to an assembly reducing the chance of accidental loosening.

How are washers sized?

Washers are sized by their inner diameter.

Where can I buy washers?

You can start here: Washers

Why use washers with bolts?

Washers are used with bolts to give the nut a smooth, even surface to tighten against, better distribute pressure on softer materials and prevent pull-through.

When are lock washers needed?

Lock washers are needed when the fastener assembly is subject to vibration or wherever back off is considered an issue.

When should I use washers with bolts?

Always use a washer between the installation material and the nut.

What do washers do?

Washers provide a smooth, even surface to tighten against, better distribute pressure on softer materials and prevent pull-through.

What is the difference between flat washers and fender washers?

Fender washers have a much larger outer diameter than standard flat washers, allowing for better load distribution and coverage of larger holes.

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