Nuts and Washers

Nuts and washers are small but integral for many fastening jobs

Nuts and Washers

There are a huge variety of nut and washer types. When making a selection you nut determine what function you need them to perform.

Tip: Nuts and washers are sized in both U.S. and metric measurements.

Uses and Materials

Nuts are used to secure a bolt or screw and washers distribute pressure, relieve friction and prevent leaks. Both nuts and washers can be made from an array of metal and nonmetallic materials.

Nut Types

The best way to ensure you have the right nut is to check and see if its classification matches the screw or bolt you are using. 

Learn more about the different types of nuts available in the chart below.

Nut Type Description Applications

Acorn

  • Features a pointed top
  • Covers protruding fasteners

Cap

  • Features a rounded top
  • Covers protruding fasteners

Coupling

  • Long and slender
  • Joins together lengths of threaded rods

Hex

  • Available in a wide range of sizes
  • General uses Clamping and joining

Knurled

  • Round, textured exterior allows for easy gripping
  • Attaching diffuser shields on electrical fixtures

Locking

  • Available in different types
  • Nylon-insert locking nuts feature a nylon interference washer
  • Prevents bolts from loosening under vibration

Machine Screw

  • Used with smaller screws
  • Secures and joins machine screws

Serrated Flange

  • Features a built-in washer
  • Combines the qualities of a locking nut and a hex nut

Speed

  • Thin and flat
  • Secures fasteners where there is low clearance

Square

  • Square-shaped
  • General applications

T

  • Features three sharp prongs with short barrel lengths
  • Fastens wood, particle board and composite materials to leave a flush surface

Tensilock

  • Features ratchet teeth inside the base
  • Distributes loads during fastening Holds tightly
    under vibration

Wing

  • Features wings that allow you to twist it by hand
  • Easy-on, easy-off fastenings

Washer Types

Most washers have a constant thickness but some, like spring washers, feature an open construction that allows the thickness to vary.

Learn more about the different types of washers available in the chart below.

Washer Type Description Applications

Bonded

  • Provide a low-profile
    appearance
  • Used in conjunction with a gasket

Countersunk

  • Available in a number of
    shapes, including angle,
    flanged, 90° and more
  • Removes the need to drill a countersunk hole with
    flat-or oval-head screws

Dock

  • Has a larger outside
    diameter and thickness
  • Distributes force evenly

Fender

  • Has a large outside diameter
  • Covers large and oddly sized holes

Fiber

  • Made of vulcanized fiber
  • Used in conjunction with an insulating washer or
    gasket

Finishing

  • Available in brass and stainless steel
  • Provides a finished look with round or flat screw heads

Flat

  • May be regular or high strength
  • General uses Prevents marring of surfaces

Lock

  • Provides spring action
  • May have a high collar
  • Prevents loosening due to vibration

Machinery Bushings

  • May be made of flexible,
    nonmetallic material
  • Takes up slack between machinery parts

Rubber

  • Made of hard rubber
  • Sealing

SAE

  • Has a small outside diameter
  • Automotive

Spiral Split

  • Often used in conjunction with a flat washer
  • Locking

Spring

  • May be helical or conical
  • Increases elastic properties of a joint

Tension

  • Made of spring steel
  • Eliminates rattles, side play and lost motion in linkages
  • Connects levers and gear shift rods

Tooth Lock

  • Teeth may be internal or
    external
  • Bites into surface to lock into place

Features

Gaskets. Best used to seal areas where there s a possibility of gas or liquid leakage.

Single-Thread Nuts. Can be used instead of multiple-thread nuts for lighter-duty applications. Requires less torque and reduces the number of parts you’ll need.

Kits. Nuts and washers often available in kits providing large numbers of several different types of each.