Hey guys, I was milling some hot rolled steel on my diy cnc, my feed rate was 59 inches per minutes, 0.039 inch depth of cut, 0.60 inch radial cut, at 15,000 rpm on a 5/8" single carbide insert cutter. I am not using any water coolant, there were many sparks, many blue chips, I was expecting my insert to be destroyed... when I stopped the spindle, I felt my end mill & insert, it was cold, not even warm, it was flat out cold. How is this possible? The blue chips were extremely really hot & my work piece was warm. Is this some kind of anomaly?