Types of washers
Contents |
[edit] Introduction
A washer is a thin disc-shaped plate, typically with a hole through the centre, that is used in conjunction with a threaded fastener (such as a screw or bolt) to:
Washers are most commonly made from metal or plastic, although rubber and fibre versions are also available.
Although they can vary widely, in general, washers have an outer diameter that is approximately twice the inner diameter.
There are three main categories of washer:
[edit] Plain washers
Also known as a flat washer, this type of washer is a flat annulus or ring which is used to spread the load of a screwed fastening and prevent damage to the surface being fixed.
Types of plain washer include:
- Penny washer (or Fender washer): A flat washer with a larger outer diameter proportional to the central hole, meaning it can distribute loads more widely.
- Spherical washer: Consists of one radiused surface which, when used with a mating nut, allows for several degrees of misalignment between parts.
- C-washer: Can be slid in and out of position on a bolt or shaft.
- Countersunk washer: When secured, this type of washer creates a flush surface.
[edit] Spring washers
This type of washer has axial flexibility which helps prevent fastening or loosening as a result of vibrations or shock.
Types of spring washer include:
- Belleville washer: Has a slight conical shape which helps maintain tension in assemblies where there is thermal expansion and contraction.
- Curved disc spring: Is only curved in one direction and so is used to support relatively light loads with a wide deflection range.
- Wave washer: Has a ‘wave’ in the axial direction which makes it suitable for use as a cushion spring or spacer.
- Split washer: Has a ring that is split at one point and bent into a helical shape creating more friction and rotation resistance.
[edit] Locking washer
This type of washer is often interchangeable with spring washers and prevents fastening or loosening rotation.
Types of locking washer include:
- Helical spring: Increases the pre-load on the fastener while tightening. This provides protection against loosening.
- Toothed lock washer: Has serrations around its edge that can extend inward or outward to bite into the surface material and provide maximum torsional resistance.
- Tab washer: Has a side tab that can be bent into place against a nut, preventing rotation.
[edit] Related articles on Designing Buildings Wiki
Featured articles and news
Gregor Harvie argues that AI is state-sanctioned theft of IP.
Many resources for visitors aswell as new features for members.
Using technology to empower communities
The Community data platform; capturing the DNA of a place and fostering participation, for better design.
Heat pump and wind turbine sound calculations for PDRs
MCS publish updated sound calculation standards for permitted development installations.
Homes England creates largest housing-led site in the North
Successful, 34 hectare land acquisition with the residential allocation now completed.
Scottish apprenticeship training proposals
General support although better accountability and transparency is sought.
The history of building regulations
A story of belated action in response to crisis.
Moisture, fire safety and emerging trends in living walls
How wet is your wall?
Current policy explained and newly published consultation by the UK and Welsh Governments.
British architecture 1919–39. Book review.
Conservation of listed prefabs in Moseley.
Energy industry calls for urgent reform.
Heritage staff wellbeing at work survey.
A five minute introduction.
50th Golden anniversary ECA Edmundson apprentice award
Showcasing the very best electrotechnical and engineering services for half a century.
Welsh government consults on HRBs and reg changes
Seeking feedback on a new regulatory regime and a broad range of issues.
CIOB Client Guide (2nd edition) March 2025
Free download covering statutory dutyholder roles under the Building Safety Act and much more.