Downtime

A deep hole drilling machine that is down costs more per hour than almost any other machine in the shop. The hourly burden rate is high, the parts going through it are usually high-value, and the whole production schedule backs up when one machine stops. I have spent years learning what keeps these machines running, and most of what works is not in the maintenance manual. Here is my approach to reliability — what I actually do, not what the textbook says. ...

Deep hole drilling machines are specialized equipment. When a part fails, you can’t always get a replacement quickly. Having the right spares on hand can mean the difference between hours of downtime and days. Here’s what I’ve learned about stocking spares. Critical Spares These are parts that fail without warning and cause immediate downtime: Part Why It Fails Cost Lead Time Rotating union seal Wear, normal $50-$200 2-5 days Coolant hose Burst from pressure cycling $100-$500 1-3 days Guide bushing Wear, normal $50-$200 1-5 days Spindle drive belt Fatigue $100-$300 2-5 days Door interlock switch Coolant contamination $50-$150 2-5 days I keep at least one of each of these on hand for every machine. ...