Castle Nuts 304 Stainless Steel, also known as 18-8 Stainless Steel. Castle nuts are used in conjunction with a cotter pin to prevent loosening. A castellated nut, also called a castle nut or slotted nut, is a nut with slots (notches) cut into one end.
The bolt or axle has one or two holes drilled through its threaded end. The nut is torqued properly and then, if the slot isn't aligned with the hole in the fastener, the nut is rotated to the nearest slot. The nut is then secured with a cotter pin or safety wire. Castellated nuts are used in low-torque applications, such as holding a wheel bearing in place.
304/18-8 Stainless Steel is the fastener industry standard grade for Stainless Steel, and has corrosion resistant properties making 304 Stainless Steel Castle Nuts suitable for fresh water, external, and long lasting applications.