Here's something that might be of interest to the machining guy's here.....the part being machined in the video is D-2 Tool Steel that is heat treated to 60-62 Rc..........these are Embossing Punches for one of our customers and there is a .250 transition radius between the flats....we used to grind all the flats and then Paddle on the Radius in the Jig Grinder....It used to take about 2-2 1/2 hours in grinding..........Watch the chips flying of the punch......Remember.....the part is 60-62Rc............It's all in the coating of the carbide end mill...........Wild Stuff......Between 16 pc's we held size w/ .0002
Ken