I have to train our GSAs (graduate studio assistants) on 3D cutting using the CNC machine today. I thought I would brush up on my skills. These are some solid maple boards. Oddly enough hardwood mills much faster than other materials. I am using a 1/2" ball end mill. Three roughing passes running at 4.1 IPS (inches per second) 18,000 rpms and two finishing passes running at 8 IPS and 18,000 rpms.