How much coolant pressure does gundrilling need?

Gundrilling relies on high-pressure through-coolant to flush chips and cool the cutting edge. The exact pressure depends on diameter and depth — smaller diameters need higher pressure. Our engineers advise per application.

How to Choose a Gundrill | Specification Guide

How to choose a gundrill: diameter, material and coolant

Choosing the right gundrill comes down to a handful of factors. Get them right and you’ll hold straightness and finish while maximising tool life. Here’s the checklist we work through with customers.

1. Diameter and depth

Start with the hole: its diameter and its depth-to-diameter ratio. This sets the tool size and confirms whether gundrilling is the right method (versus BTA for larger diameters).

2. Material

The workpiece material drives the tool grade, geometry and coating. A gundrill for stainless is not the same as one for cast iron or aluminium.

3. Coolant pressure and flow

Gundrilling depends on high-pressure through-coolant to evacuate chips and cool the edge. Your machine’s coolant capability is part of the specification — insufficient pressure is a common cause of poor results.

4. Tolerance and finish

If the hole must hold tight tolerance or fine finish, the gundrill can often deliver it directly, removing a secondary operation. That target shapes the geometry.

5. Resharpening

Gundrills are designed to be reground. If uptime matters, pair the tool with an in-house resharpening machine.

Not sure where to start? Send us the part details and we’ll specify it.