Installing A Castle Nut

Castle nuts are nuts that look like crowns or parapets of mid evil castles. These nuts are used together with a bolt and a cotter pin to create a secure nut in place so that it cannot be tightened or loosened.

Before We Begin:

In order to install a castle nut you will need:

• Castle Nut
• Cotter Pin
• A Bolt with a hole

You can find bolts that come with pre-drilled holes for castle nuts, but you must know the length of the bolt you will need. If you do not have a bolt with a pre-drilled hole, you may drill your own, we can talk about that in another post. In this post, we will drill out own hole to show you how to make one yourself for better sizing.

Step One:

Now that you are ready to begin, slide the bolt through the installation material and screw the castle nut onto the other side. You can use a sharpie or pencil to mark the area where you need the hole to be (inside the peaks of the nut). Then remove the nut and bolt and place the bolt into a vice.

Step Two:

Screw the nut back onto the bolt and align it with the mark you drew earlier. This will serve as the drilling point. Use a punch to create an indent into the bolt so your drill bit has a starting point. Make sure you drill perpendicular to the hole so that it comes out in between the peaks on the other side as well.

Step Three:

After you have drilled your hole, remove from the vice and place back into your installation material. For the purpose of this blog, we have left ours in the vice as we did not have an installation material readily available. Once it is back in the material place your cotter pin through the hole. Take a pair of pliers and bend the cotter pin out away from the center on each side. This will create a locking effect and the pin will not be able to fall out.