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Castle and Slotted Nuts
Tuesday 8th November 2022
Trojan Special Fasteners Ltd can manufacture all manner of slotted and castle nuts.
Castle nuts are typically hex nuts with usually 6 slots (60 degrees apart) in a reduced diameter round section above the wrenching part. When a castle nut (or any radially slotted nut) is applied to a threaded section, it is tightened so that its slot is aligned with a predrilled hole in the bolt or threaded rod, into which a cotter pin, split pin, a lock wire or a spring pin is typically inserted to stop the nut from rotating.
These kind of nuts are unsuitable when a specific preload is required because the torque can't be fine-tuned - a result of rotating a nut to align it with a hole for pin insertion. Additionally, such nuts require an additional component and alignment time.
Typically split pins, cotter pins, R clips or safety wires can be used to stop the castle nut from loosening.
Castellated, slotted and castle nuts are commonly used on axles and are even called axle nuts in some applications. Sometimes they are used on trailers too. They are also used as hub nuts which hold the driveshaft within the wheel hub assembly.
In addition to standard preferred sizes, we also manufacture non-preferred and non-standard or special thread and nut forms and sizes. If you have a drawing or a sample Trojan Special Fasteners Ltd will make what you want.
We can manufacture from single quantities all the way up to the thousands.
What are slotted nuts used for?
Castle and slotted nuts are primarily locking nuts, which means that once they are fixed they are designed to lock into position. This is achieved by using a cotter, split or taper pin or wire which winds around the castle or slotted portion of the nut and through a pre-drilled hole in either a bolt or portion of threaded rod. In this way, the pin stops the nut from moving free by impeding its movement due to the slots it passes through.
What is the difference between a castle nut and a slotted nut?
The primary difference is that castle nuts have a turned-down (turret) portion on the slotted end. With a castle nut, a pin can be wound around and pinned against the turret portion in order for the pin not to stick out too much. Otherwise castle and slotted nuts are effectively the same.
This is the singular main item we help our customers with. Nomenclature is key to ensure you get the right nut for the right job.
Why do castle and slotted nuts have slots?
Castle nuts and slotted nuts have slots so that they can accommodate a cotter, split or taper pin or wire, which prevents the nut from loosening.
