Night-Shift

It was 1:47 AM on a Wednesday in March, and I was already in trouble before I touched the control panel. The day shift guy, Danny, had flagged the handover log as urgent. “Drill acting weird near the end of the shift,” he wrote. “Reduced feed rate to try to finish the last part. Might need looking at.” The log was sitting on the desk in the break room where he’d left it, next to an empty coffee cup and a half-eaten granola bar. I read it, nodded to myself, and walked straight past the machine to clock in. That decision cost us almost two thousand dollars. ...

I volunteered for the night shift about five years ago and never looked back. Most guys hate it – the weird sleep schedule, the social isolation, not seeing your family for dinner. But for running a deep hole drilling machine, night shift is the best time to work, and I will die on that hill. The day shift at our shop starts at 6 AM and by 7:30 the place is a zoo. The material handling guy is dropping off pallets of blanks. The quality engineer is walking around with a stack of inspection reports, asking questions about every job. The production manager is running around putting out fires. There are safety meetings, toolbox talks, lunch orders, visitors from the front office walking through with hard hats. ...

I’d set up a job on the day shift — a 16 mm gun drilling job in 4140 steel. The setup was running perfectly. I went home feeling good about the day’s work. At midnight, my phone rang. It was the night shift operator. The machine was making a strange noise and the surface finish was poor. Could I come in and look at it? The Setup I Thought Was Perfect Let me describe what I had done that morning. The job was a batch of hydraulic spools, each requiring a 16 mm through-hole in 4140 pre-hardened steel at about 32 HRC. The bore depth was 480 mm, giving a depth-to-diameter ratio of 30:1. I had selected a new carbide-tipped gun drill, checked the guide bushing clearance with a feeler gauge, set the coolant pressure to 75 bar, and dialed in the feed at 0.06 mm/rev with a spindle speed of 4000 RPM. ...