The old machinist in Wichita who caught my crash by sound alone
About 6 months back I was running a Haas VF2 on a Friday afternoon and I thought everything sounded fine. This machinist named Ray, 34 years on the floor, walked by, stopped, and said "you lose a tool or are you trying to break that spindle?" I pulled the door open and turns out one of my roughers had pulled out of the holder about 0.040 and was cutting way too deep. He told me he heard it from 30 feet away because the spindle load had that high whine instead of the normal hum. Honest truth, most of us are staring at the load meter instead of actually listening to the machine anymore. I always keep my ear on the cut now, and if you spend all day with headphones in you are going to eat a crash you could have heard coming. So what do you guys hear that tells you something is off before the meter does?
I'm so bad at this that I once heard a weird noise and just turned the feed down til it "sounded normal" again, turned out my insert was toast. Ray would have slapped me. Now I catch myself taking my earbuds out just to listen, which feels kinda dumb til it saves you a spindle.