A split pin has two long tines that are bent to hold it in place. 50 out of 5 stars 9.

Amazon Com Blue Print Adn187137 Tie Rod End With Castle Nut
Castle nut cotter pin. With a finger or tool bend the long end up and over the end of the bolt or shaft tap it down tight. One leg of the pin is bent back against the flat of the nut the other is bent up around the end of the axle and pressed tight against the axle end. 50 out of 5 stars 7. In this example note the head of the cotter pin is set parallel to the length of the axle and is actually set down into one of the notches of the castle nut. Also known as castle nuts secure these nuts by inserting a cotter pin or safety wire through the slots and a drilled hole in your bolt for mild loosening resistance. The flat sides of slotted nuts extend fully from the top to the bottom of the nut.
This pin prevents the nut from turning and loosening. Maybe they will be ok but why take a chance. I just wanted to show you how this would work. A few specs on this the length on the bolt from the underneath of the head to the end is 4 1116. King kutter rotary cutter castle nut and cotter pin code 501110. If you use a castle nut and wire or cotter pin the nut will never come off.
Height includes the slots. Use cotter pins to lock a castle nut or secure a clevis pin. Not true with the prevailing torque or nylock nuts. Caltric set of 2 rear axel castle nuts pins compatible with honda trx300 fourtrax 300 1988 2000. Theyre not recommended for use on parts exposed to high vibration because the pin is prone to shearing under prolonged stress. Bend the short end down over the face of the nut trimming as required to prevent snagging yourself later.
Both castellated and slotted nuts are designed to use a pin usually a cotter pin that fits through the slots and through a hole in the screw to which the nut is attached. It includes the castle nut and the cotter pin to lock it into place. Hairpin clips also called r clips are designed to slip on with no bending required. I too was schooled to move the nut to the closest location for the hole in the rod bolt. Cotter pins are not included. A cotter pin is easy to install and remove and is commonly used to secure a wheel or machine component on an axle.
The diameter is 78 of an inch. The longer end of the cotter pin is up so its easy to grab.