When Should You Use Coolant Through Carbide Drill Bits

A practical decision framework for CNC shops to improve tool life, chip control, and productivity—only where it truly pays off.

By Senior Application Engineer, Amony Cutting Tools    ·    Published: December  30,  2025     ·     Views: 1086

Coolant through carbide drill bits feature precision-engineered internal channels running from the shank to the cutting edge. High-pressure coolant (typically 10–50 bar) exits directly at the tip—exactly where heat and chips are generated.

Compared to standard external flood cooling, internal coolant delivery offers measurable advantages in demanding CNC drilling operations.

Why shops switch to thru-coolant drilling:
  • Direct cooling: reduces cutting-zone temperature by up to 200°C

  • Superior chip evacuation: prevents packing and re-cutting

  • Improved lubricity: minimizes built-up edge (BUE)

  • Extended tool life: typically 2–3× longer in difficult applications

On this page
  1. 8 key scenarios when thru-coolant drilling makes sense

  2. Quick decision rule

  3. Benefits vs. drawbacks

  4. Implementation tips

  5. Real-world aerospace case study

8 Key Scenarios When You Should Use Coolant Through Carbide Drill Bits

#ScenarioWhy Use Thru-CoolantKey BenefitsTypical Applications / MaterialsRecommended Series
1Deep Hole Drilling (L/D > 5×D)Chips struggle to evacuate naturally; heat builds deep in the holePrevents chip packing, reduces peck cycles, improves straightnessStructural steel, aluminum stacks, L/D 10–30×DAmony LXD Series + ICF
2High-Speed Machining (>2000 RPM)Higher surface speeds generate heat rapidlyMaintains edge sharpness, supports aggressive feedsTitanium, Inconel, high-temperature alloysAmony ICF Series
3Difficult-to-Machine MaterialsSticky or abrasive materials cause BUE and rapid wearImproved lubrication and cooling at the cutting interfaceStainless 304/316, HRSA alloysAmony ICF Series
4High-Volume Production RunsDowntime from tool changes becomes costly2–3× longer tool life, consistent hole qualityAutomotive components, aerospace partsAmony UPX / ICF Combo
5Precision or Tight-Tolerance HolesThermal expansion affects size and surface finishReduces thermal distortion, improves roundnessMedical devices, hydraulic fittingsAmony UPX Series (Coolant Option)
6Poor Chip Formation EnvironmentsLong, stringy chips overwhelm external coolingForces chips upward for stable evacuationAluminum alloys, low-carbon steelsAmony ICF Series
7MQL or Near-Dry MachiningExternal coolant delivery is limited or absentEnsures consistent lubrication at the cutting edgeEco-focused shops, selected compositesAmony ICF Series
8Stacked or Multi-Material DrillingExternal coolant cannot penetrate between layersCools and lubricates throughout full depthComposite-metal stacks, laminated partsAmony LXD / ICF Series

Quick Decision Rule

If your hole depth exceeds 5× diameter, you are running high speeds or feeds, or you are machining  heat-sensitive or sticky materials—coolant through drilling is strongly recommended.

For shallow holes (<3×D) in mild steel with effective external flood cooling, standard carbide drills are often sufficient.

Benefits vs. Drawbacks — A Balanced View

Advantages
  • Tool life extension: 100–300% in deep-hole applications

  • Higher productivity: feeds increased by 20–50%

  • Improved hole quality: better roundness, fewer burrs

  • Reduced machine load and vibration

Drawbacks
  • Higher initial cost (typically 20–50%)

  • Requires thru-coolant capable spindle and toolholder

  • More complex regrinding requirements

In most production environments, productivity gains offset the added cost—often within the first batch.

Real-World Example: Aerospace Supplier Cuts Costs by 40%

An aerospace supplier was drilling deep holes (15×D) in Ti-6Al-4V components.  Using external coolant drills, they averaged only 80 holes per tool with frequent peck cycles.

After switching to Amony ICF Series coolant through drills, the process ran continuously at higher feeds.  Tool life increased to 250+ holes per drill, peck cycles were eliminated, and cycle time dropped by 25%.

Result: 40% reduction in tooling cost and significantly more stable production.

Ready to Optimize Your Drilling Process?

Coolant through carbide drill bits are not a luxury—they are a necessity when heat and chip control limit efficiency. The key is using them only where the application demands it.

Explore our ICF and LXD coolant through series or contact us for a free application review, sample testing, or custom quotation.

Ready to Improve Your Machining Performance?

Contact our experts today for a free quote or technical consultation.