Difference Between Shim and Washer

Shim and Washer might seem the same but when used in the real world are completely different. These tools serve different purposes and at times one can be more beneficial than the other. In simple words, Shim is used to adjust the gap, and Washer is used to distribute the load of screws/nuts.

Shim vs Washer

The main difference between Shim and Washer is Shim is used as a spacer, to adjust the gap between uneven objects. On the other hand, Washer is used to distribute the load in case of a threaded fastener. These two objects are often used interchangeably to accomplish any project.

Shim and Washer

A shim is a thin tapered piece of material that is used to adjust the space between two objects. A shim can be made up of various materials such as wood, metal, plastic, and stone. An object subject to wear and tear is often prevented for so using a shim.

A washer is shaped like a thin plate or doughnut-shaped with an outer radius bigger than the inner one. The small hole structure helps to distribute the load of a screw or nut. When a washer is used, there is a lesser or negligible chance for the fastener to break into a heavyweight situation.

Comparison Table Between Shim and Washer

Parameters of ComparisonShimWasher
Definition/purposeUsed to adjust the space between two surfacesUsed to distribute the load of a bolt or nut
Material usedWood, metal, plastic, stoneMetal, plastic
ShapeWedged or tapered or any shapedonut
Contribution to reducing frictionPrevents wear and tearPrevents the fastener to break
Commercial uselaminatedSteel

What is Shim?

Shim is a thin material whose shape depends on the space where it is to be used. It helps in the prevention of wear and tear by leveling the surface. High-quality shims are available for commercial purposes in laminated form but in practical life, a shim is made at the spot to level an uneven surface.

In the automobile industry, shims are placed between the bucket tappets controlling the valve clearance which can further be adjusted by thinning or thickening the shim.

In the assembly of any object, precision metal shims are used to furnish the finalized product in the way specified by the product’s drawing specialist. In machinery installations, shims are required to adjust the flexibility of motors, pumps, etc.

The most common situation to observe the importance of shim is carpentry. During the construction of wooden structures, small pieces of wood are used to fill the gaps between large timbers.

Musicians also use a shim to adjust the pitch and tones of their musical instruments. To prevent heat sinks in the central processing unit of printed circuit boards, CPU shims are used.

Shims are used to obtain pure Lorentzian line shapes with differing spectrums. This is done by my manual shimming of individual shims or automatic shimming process.

What is Washer?

A washer is a disk-shaped material that distributes the load concentrated on a screw or bolt or nut. It is used as a spacer, locking device, reduces vibration or friction, wear and tear or can be used as an insulating device. The first use of a washer was recorded back in 1346 but the proper definition was explained back in 1611 as per reports.

 High-quality hardened steel washers are used to prevent pre-load caused due to brinelling (permanent indentation of a surface) after torque is applied. They are also used to prevent galvanic corrosion by insulating the surface. Lubrications or coatings are done to tackle wear and tear.

Washers are used in tube wells for the smooth drawing of water from underground. Washers are often mistaken with gaskets which are used as a seal against water leaks.

Washers can be divided into three types – Plain washers, spring washers, locking washers.

Plain washers – spreads the load and prevents damage to fixed surfaces by providing insulation. For example, electrical. Anchor plate or wall washer also comes under this category.

Spring washers – come with axial flexibility and prevent fastening or loosening caused due to vibrations. It is also called a Belleville washer or cupped spring washer or conical washer (depending on its shape). Other types of Spring washers are curved disc springs, wave washers, tab washers, wedge lock washers.

Locking washers – prevents fastening or loosening caused by the rotation of the fastening device or over time.

Spring and locking washers are similar in some cases.

Main Differences Between Shim and Washer

  • Shim is used to providing an even surface by filling the gaps, giving support to the structure whereas the washer is paired with a screw or bolt or nut to increase the durability of the system.
  • Shim has no specific type rather comes in different shapes, often instantly made considering the gap whereas washers come in three types depending on torque, rotation, friction, or vibration.
  • Shim can be a wooden block, a steel plate, a small plastic piece, etc. whereas a washer is available in the form of metal or plastic only.
  • Shim might be needed in any everyday lifehacks whereas washers are specially used in the automobile industry or construction sites.
  • There is no specific year when the use of shim was first observed whereas washer is recorded to be used since 1346.


Shim and washers are two important materials that help to overcome issues of stability in construction or prevent unwanted friction that leads to wear and tear. Shim can be easily made using some other material to fill a space but the washer needs proper measurement like the diameter of the outer circle should be twice that of the inner one and there should be a hole. Also, it should fit against the nut or screw or bolt for which you need it. Washers and shims can be used interchangeably to meet any certain need. Be it adjusting the uneven leg of a table or fitting the tap of the basin, shim and washer work appropriately in such situations.  


  1. https://journals.lww.com/implantdent/FullText/2012/04000/Effect_of_Using_a_Titanium_Washer_on_the_Removal.15.aspx
  2. https://journals.sagepub.com/doi/abs/10.1177/0954406215622496
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