I've built a few 3D printers, but I'd like to build either a 4 axis or 5 axis router/or mill. I'm thinking more of a 4 axis lathe type setup, but I have a couple questions: 1.) Are there currently any opensource CAM programs for 4 or 5 axis machines? 2.) I'd like to use my arduino Mega 2560 and RAMPs, but I'm concerned with computing power for the rotary axis. Also I'm a noob with programming, what would be the best firmware and/or how to modify it for 4 axes? 3.) Any low cost suggestions for alternatives to the above? Thanks for the info!