The document discusses the manufacturing process and material selection for different parts of a knuckle joint. It describes how the fork, eye, pin, collar, and split pin can be cast, fabricated, or forged from steel or wrought iron. It notes that in the illustrated knuckle joint, the rods are integral with the eye and fork. Bearings may be provided in the fork. Good proportions for a steel knuckle joint without bearings are also provided.