Quick-Reference

The Five-Step Troubleshooting Sequence When something goes wrong during a deep hole drilling job, I teach operators a five-step sequence. This sequence solves about 80% of all problems without needing engineering support. I post this sequence on every machine in the shop. The sequence follows the most likely cause first. Starting with the most common problem saves time. Do not skip steps and do not jump to conclusions. Step 1: Check Coolant Pressure Low coolant pressure is the root cause of more problems than anything else in deep hole drilling. It causes chip packing, tool breakage, poor surface finish, and oversized bores. ...

Overview Deep hole drilling brings its own set of challenges that standard drilling does not. The high length-to-diameter ratio (typically above 5:1), the reliance on high-pressure coolant for chip evacuation, and the single-lip cutting action of gun drills all create failure modes that are unique to this process. This guide covers the most common problems I encounter and their solutions. I use this page as my starting point when something goes wrong. Most problems have simple causes that can be checked in minutes: coolant pressure, guide bushing condition, and tool condition. I always check these three things before changing process parameters. ...

How to Use This Card I designed this quick reference card to be posted on every machine in the shop. It covers the six most common gun drilling problems and their solutions. Each entry follows the same format: symptom, most likely cause, first action. Operators who use this card solve most problems without waiting for a setup technician or engineer. I’ve seen operators resolve coolant pressure issues in under two minutes by following the card instead of waiting 20 minutes for a technician to arrive. The card does not cover every possible problem, but it covers the 90% that happen regularly. ...