Gun Drilling Machines

What Is a Gun Drilling Machine?

A gun drilling machine is a deep hole drilling machine built to run the gun drilling process — a single-lip gun drill fed through a hole while high-pressure coolant is pumped through the tool. The drill guides itself on its own support pads, which is what keeps the hole straight over depths a twist drill cannot reach. A deep hole drilling machine that uses the gun drilling method holds small diameters — from under 1 mm up to about 50 mm, and 60 mm on some models — straight and round at depth ratios a twist drill cannot hold.

That capability is why gun drilling machines show up wherever a thin, deep, precise hole has to be drilled in one pass: mold cooling channels, ejector pin holes, shaft and round rod center bores, crankshaft oil holes, hydraulic components, and medical parts. For a fuller introduction to the process, see what deep hole drilling is.

Gun Drilling vs. BTA: When Each Machine Applies

Gun drilling machines and BTA deep hole drilling machines are the two main families of deep hole drilling equipment, and they split by diameter. Gun drilling covers small bores — typically about 1 mm to 50 mm — at extreme depth ratios, using external chip evacuation through the drill's V-flute. BTA takes over for larger diameters, roughly 20 mm upward, where metal removal rate matters and chips are evacuated internally through the tool.

Some RuidCNC platforms carry both processes. A gun drilling machine with an optional BTA system, for example, drills 3–50 mm by gun drilling and then switches to BTA tooling for 25–80 mm bores on the same frame. For a fuller comparison see our large-diameter deep hole drilling service and the guide to choosing a deep hole drilling machine.

What to Compare When Buying a Gun Drilling Machine

• Depth-to-diameter ratio and straightness — the machine's real job is holding a deep, small hole straight. Ask what straightness the machine holds per unit of depth, not just the diameter range.
• Coolant pressure, flow and filtration — high-pressure through-tool coolant is the machine's heart. It clears chips and keeps the cutting edge cool in holes a twist drill cannot reach.
• Worktable size and load — match the table and load rating to your longest and heaviest part, whether that is a mold plate or a 1-metre shaft.
• Guide and whip-guide support — purpose-built machines support the drill along its length, which is what separates them from a gun drilling system bolted onto a machining center.
• Spindle configuration — single spindle for flexible job-shop work, twin or multi-spindle for high-volume production of the same part.

The buying guide walks through each specification in detail. If you are drilling mold and die work, the mold & die manufacturing page shows how the machines are applied to cooling channels, ejector pins and hot runners.