Old timer told me to run a 1/2 inch end mill at 800 SFM in 6061. Sounded crazy but I tried it.
He said the high speed would work if I kept the chip load light, like 0.003 per tooth. My machine is a 2015 Fadal. I ran it, and the finish was perfect, no chatter at all. But my lead hand says that's way too fast and will wear the spindle bearings. Who's right here? Has anyone else pushed speeds that high on older machines?