Castle Nuts in Brass

Locking Nuts for use with a Cotter Pin or Safety Wire

Castle nuts are used in conjunction with a cotter pin to prevent loosening. This nut has slots (notches) cut into one end. The name comes from the nut's resemblance to the parapets of a castle.

Castle nuts are installed much like any other hex nut, simply being fastened to a bolt or axle. The installation differs in that the bolt or axle has one or two holes drilled through its threaded end. If the castle nut's slot isn't aligned with the bolt or axle's hole, the nut is rotated to the nearest slot. The nut is then secured with a cotter pin or safety wire to the bolt or axle. This cotter pin is then bent to secure the castle nut to the bolt. This completes the locking action.

Castellated nuts are used in low-torque applications, such as holding a wheel bearing in place.

Brass

Brass is an alloy made of copper and zinc. The color of brass can vary from dark to light based on the zinc content; more zinc content produces lighter brass. Brass is prized for its appearance and is often used decoratively. However, it is quite soft, so it is not suitable for all applications. Brass conducts electricity and is also a good conductor of heat.

Nut Sizes Width Across Flats Overall Height
1/4"-20 0.434" REF 0.281" REF
5/16"-18 0.499" REF 0.326" REF
3/8"-16 0.562" REF 0.410" REF
1/2"-13 0.745" REF 0.569" REF
5/8"-11 0.934" REF 0.724" REF
3/4"-10 1.125" REF 0.820" REF

FAQs

What is a castle nut used for?

Castle nuts, or castellated nuts, are used in low-torque applications as a kind of lock nut. They, combined with a cotter pin, lock an assembly down. A notable example of their use is in holding a wheel bearing.

What is the difference between a slotted nut and a castle nut?

The main difference between the two is that castle nuts have a round section at the top where the slots are. Slotted nuts have their slots cut into the nut itself. While functionally the same, the added rounded top of the castle nut allow the installed cotter pin to be installed closer to the nut, almost flush, for added secureness.

What fasteners are used to lock castle nuts?

Tradiationally, castle nuts are locked with cotter pins or split pins. R-Clips and safety wire have also been known to be used for installing castle nuts.

How strong is brass?

Brass is stronger and harder than copper, but not as strong or hard as steel. It has great formability and is resistant to saltwater corrosion.

What is brass made of?

Brass is an alloy of copper and zinc. The color of brass can vary from dark to light based on the zinc content; more zinc content produces lighter brass.