What type of washer is designed specifically to help prevent loosening of fasteners?

• A. Flat washer
• B. Lock washer
• C. Fender washer
• D. Galvanized washer

Answer: (B)

A lock washer is specifically designed to prevent the loosening of fasteners due to vibrations or movement. These washers are commonly used in mechanical assemblies where constant movement occurs. Their unique shape often includes a split or bent design that creates tension against the nut or bolt, thereby increasing friction and resisting any motion that might cause the fastener to loosen over time.

In contrast, flat washers are primarily used to evenly distribute the load of a fastener across a surface. While they may provide some benefits in terms of surface protection and load distribution, they do not actively serve to secure the fastener against loosening.

Fender washers, known for their larger outside diameter relative to their inner diameter, are used in applications where a larger surface area is needed. They help to distribute load as well but do not have any locking mechanism to prevent loosening.

Galvanized washers, coated with zinc for corrosion resistance, similarly do not possess features that specifically address the prevention of loosening; they primarily serve a protective function.

Therefore, the lock washer is the most effective choice for applications where the goal is to maintain the integrity of the fastening joint under dynamic conditions.