https://www.superiorwasher.com/washers/8829/Fender-Washers.html
The following clip describes washers that have a larger outer diameter in relation to the central hole or inner diameter. These are fender washers and they are used where fastening becomes difficult due to corroded and worn-out holes. Their oversized outer diameter provides more bearing surface for load distribution of the fastener.
The most common applications in which fender washers are the perfect fastening material include auto body repair, sheet metal, electrical or electronics, commercial appliances and in plumbing installations. These washers are manufactured to fit standard bolt sizes and use different materials depending on the application for which they will be used. They can be manufactured to custom specifications of the application.
Want to see more mechanical engineering instructional videos? Visit the Cal Poly Pomona Mechanical Engineering Department’s video library, ME Online (https://www.cpp.edu/meonline).