[Tristan Lall]

Extrusion requires a difficult setup and expensive tooling; it's only cheap in huge volumes. But what about graphite permanent mould casting? If you can get a local casting shop to sponsor you, it wouldn't take much to make a few hundred links.

Basically, you'd need to mill out the mould into two graphite halves with sprues, vents and risers as necessary (usually CNC—a casting shop will be able to do this easily), and it's just a matter of mounting it to a standard fixture (which opens and closes the halves) before you're ready to pour metal (e.g. 390 aluminum).