Universal Milling Arsenal
4 Axis CNC Machining in 2021: The Definitive Guide used universal mill arsenal fu 251. CHAPTER 1: Introduction to 4 Axis CNC. 4th Axis machining is an interesting and important subpart of the CNC milling world. Haas actually got it's start building a 4th axis before it ever built entire CNC machines (pictured on the right).