• A lock washer is used to prevent a bolt or nut from loosening under vibration.
• The split ring lock washer is being rapidly replaced by lock washers designed for specific applications.

• Split lock washers are helical-shaped split rings.
• When fastened, the two ends exert a spring force on the fastener to create increased friction and resistance to motion.
• Helical spring lock washers are the most common form of the lock washer and are best suited to applications with smaller loads.

Types of washers:

• plain or flat washers
• taper washers
• spring washers
• tab washers
• toothed lock washers

Tooth-type lock washers:

• These washers have teeth that bite deep into both the screw head and work surface.
• Their design is such that they actually lock lighter as vibrations increase.