Gun Drilling Coolant Requirements: Minimum Pressure and Flow by Diameter

Every time I talk to a shop that wants to start gun drilling, the question comes up: how much coolant pressure do I really need? The manufacturer’s spec sheet usually says 1000-2000 psi. But real-world results vary depending on diameter, depth, and material. Here is what I have found works — and what does not. Pressure vs Flow: What Matters for Chip Evacuation Coolant does two jobs in gun drilling: it lubricates the cutting edge and it pushes chips back along the flute. Lubrication needs pressure. Chip evacuation needs flow. You need both. ...

June 16, 2026 · Engineer at the Deep Hole