The Bantam Tools Desktop CNC 4th Axis Accessory supports both index milling and continuous milling. If you’re programming parts that call for index milling, you can use a free version of Autodesk’s Fusion 360 for personal use. The free version of Fusion 360 only supports 2- and 3-axis machining. Remember, index milling is very similar to 3-axis machining because the 4th axis will rotate the part, but come to a stop before the Bantam Tools Desktop CNC Milling Machine starts milling. For many designs, you will be fine using the indexing approach for 4th axis machining.
However, if your designs call for continuous milling—true 4th axis machining, where the rotational axis is turning while you’re milling—you need to purchase Autodesk’s Machinist Extension for Fusion 360. Once you’ve chosen your plan, follow Autodesk’s instructions to download and install Fusion 360. Please reach out to the team at Autodesk if you have any questions.
Note: If you discover other ways to generate continuous milling toolpaths, let us know.