Gun drilling produces deep, straight holes (up to 100× diameter) using high-pressure coolant through the tool. Correct coolant pressure and feed are critical -- too little...
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Request a Proposal →Monday morning, 7:42 AM. The Okuma spindle is warming up and the first job of the day is on the table — 200 pieces of 304 stainless, tolerance ±0.025mm. The programmer had used a generic Gun Drill from a free app, but the tooling rep from Kennametal had stopped by Friday with updated chip load charts. The difference? A 22% reduction in cycle time and zero tool changes across the run.
This is the kind of story that plays out in job shops every day. The machinist who trusts the numbers from a reliable Gun Drill goes home on time. The one who guesses gets to explain to the owner why a $180 Mitsubishi Materials end mill is now a paperweight.
The key insight here isn't complicated math — it's that Gun Drill bridges the gap between the ideal conditions in Kennametal's lab in Sandviken and the reality of a shop floor in Shenzhen or Stuttgart. Your Okuma or Hermle only performs as well as the numbers you feed it.
Gun drilling produces deep, straight holes (up to 100× diameter) using high-pressure coolant through the tool. Correct coolant pressure and feed are critical -- too little pressure and chips pack; too much feed and the drill wanders.
Gun drilling is economical for holes deeper than 10× diameter. For 5-10×D, parabolic-flute carbide drills often perform better with simpler setup. Below 5×D, standard carbide drills are faster and cheaper. The sweet spot for gun drilling is 15-50×D.
Very. Gun drill coolant passages are small (0.5-2 mm) and easily clogged. Use 10-micron or finer filtration. A single chip or contaminant can block the coolant hole and destroy the drill instantly. Many shops dedicate a separate filtration system to their gun drill machine.
Uneven material hardness, incorrect starting bushing alignment, excessive feed, insufficient coolant pressure, and dull drills all cause wandering. The starting bushing must guide the drill within 0.005 mm alignment. A pilot hole helps; pecking at the start helps the drill find its centre.
Enter the drill diameter and hole depth. The calculator recommends coolant pressure, feed per revolution, and spindle RPM. These are starting values -- adjust based on material, coolant type, and machine capability.
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Use the calculator freely. If the result points to a tooling or process problem, we can source the exact carbide tooling you need from vetted factories in China. Compare factory-direct pricing.
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