Deep hole drilling—defined as any hole with a depth-to-diameter ratio greater than 10:1—is common in industries such as aerospace, mold making, medical, and energy. However, the deeper the hole, the greater the risk of tool overheating, chip clogging, and premature wear. That’s where carbide drill bits with coolant holes come in as a solution that professionals across sectors trust.
Carbide drill bits with coolant holes (also called internal coolant drill bits) are precision tools made from tungsten carbide, designed to channel coolant directly through the body of the drill to the cutting edge. The result is faster chip evacuation, better temperature control, and longer tool life, especially in demanding deep-hole or high-speed drilling applications.
As drilling depth increases, so does friction and heat at the drill point. If not properly cooled, heat can cause rapid tool wear and dimensional inaccuracy.
Coolant-through drill bits address this by delivering coolant directly to the cutting zone, maintaining thermal stability even under aggressive cutting parameters.
According to a 2021 study published in the International Journal of Machine Tools and Manufacture, internal coolant systems reduce cutting zone temperatures by up to 40% compared to external methods.
Chips that don’t evacuate properly become compacted in the flutes, leading to tool breakage or bore damage.
Coolant pressure helps flush out chips continuously—keeping the flutes clear and preventing downtime.
Though carbide drills with coolant holes cost more upfront, they offer significantly longer service life and reduce tool replacement frequency, especially in stainless steel, titanium, and Inconel machining.
Coolant drills reduce deflection, minimize built-up edge, and help maintain straightness over long drilling distances, delivering better tolerance and finish.
Aerospace Components: High-strength alloys, tight tolerances
Mold and Die Industry: Deep waterline or ejector pin holes
Medical Implants: Clean boreholes in titanium or stainless steel
Oil & Gas Industry: Long hole drilling in tool steels and superalloys
When you experience tool chipping or breakage during deep drilling
When surface finish or hole straightness is below spec
When external coolant fails to prevent overheating
When drilling materials like Hardened Steel (HRC>40), Stainless Steel, or Nickel Alloys
Look for these features when selecting your drill:
Coolant Channel Design: Straight or helical for high-pressure flow
Point Angle: 135° split point for self-centering and reduced thrust
Coating: TiAlN or TiCN for improved heat and wear resistance
Material: HRC55+ grade carbide or sub-micron grain for toughness
Explore our selection of Carbide Twist Drills with Coolant Holes optimized for stainless steel and deep-hole CNC applications.
Carbide drill bits with coolant holes are not just another tool—they’re a strategic investment for anyone serious about high-performance, deep-hole drilling. With enhanced productivity, extended tool life, and superior accuracy, these drills deliver measurable ROI in demanding production environments.
A: Most coolant-through carbide drill bits operate efficiently at 20–70 bar (300–1000 psi), depending on tool diameter and material. For deep hole applications, high-pressure coolant (50+ bar) is recommended.
A: Only if your machine supports internal coolant supply through the spindle. Otherwise, external coolant would be required, which reduces the effectiveness of internal coolant drills.
A: Stainless steel, titanium, Inconel, and hardened tool steels—all of which generate significant heat and chips during drilling—benefit greatly from internal coolant delivery.
A: Yes, but the minimum diameter is usually limited by the tool design. Common sizes start from around Ø2mm, depending on the manufacturer. Always check the coolant hole size relative to drill diameter.
A: Use clean, filtered coolant and regularly inspect coolant lines. Also avoid drilling dirty or contaminated materials that may contain abrasive particles.
Contact our experts today for a free quote or technical consultation.