I always ran my roughing passes dry until a guy at the Tulsa shop showed me his inserts
I ran carbide dry for 6 years because that is what the old timers in my first shop taught me. Last March I was at a job in Tulsa and the lead guy watched me burn through 4 inserts on one 4140 block in a single shift. He told me to flood the roughing pass and stop being stubborn. I tried it on the next part and the same insert lasted the rest of the week. I went from going through about 80 inserts a month to maybe 25. The chips come off cooler and the finish on the rough cut is way more consistent too. I still run some finishing passes dry but not roughing. Anybody else out there still running everything dry or did you switch over at some point?