There are many websites that will show you how to manufacture chain maille items, focusing on the different styles of 'weave' (how to combine metal rings together to make a protective and attractive garment) that you can use. Unfortunately, most of these guides assume that the reader already has a supply of suitable rings, and seldom guide the reader in creation of their own rings. While you can purchase pre-made rings from a number of places online, I wanted to make my own rings.
In this Instructable, I describe how to take steel wire for making electrical fences and turn it into split rings suitable for creating a chain maille garment.
While other instructables document weaving rings into garments, or how to construct a mandrel (winding rod and stand), the originality in this instructable is in the winding tool that allows for very reliable, high speed winding, that creates perfect coils of wire every time. (see step 3)
This project is also documented at my personal website