Free Online Handbook on CNC

A free online guide to CNC is available from Autodesk‘s HSMWorks group who develop CAM solutions for both Autodesk Inventor and SolidWorks. If you ever wanted to better understand the process machining and milling using CNC this would be a great resource.

CNC Handbook http://www.hsmworks.com/docs/cncbook/en/ 

Contents
Introduction & CNC Process Overview
Shop Safety
CNC Tools
Coordinate System
CNC Programming Language
CNC Operation
2D Milling Toolpaths
CNC Turning
3D Toolpaths
Milling Setups