Not all drilling jobs are created equal — especially when working with tough or high-value materials like stainless steel, titanium alloys, or heat-treated tool steels. In these applications, coolant hole carbide drill bits (also known as internal coolant drills) can significantly improve machining results.
This article explains which materials benefit most from coolant-through carbide drills, and why internal coolant is essential for productivity, tool life, and hole accuracy when dealing with difficult-to-machine metals.
Unlike standard solid carbide drills, coolant-through drills are designed with internal channels that deliver high-pressure coolant directly to the cutting edge. This feature enhances chip evacuation and heat control — two critical factors when machining hard metals or deep holes.
Stainless steel is notoriously challenging to drill due to:
Low thermal conductivity
High work hardening rate
Tendency to generate built-up edge (BUE)
Coolant-through carbide drills solve these issues by providing consistent cooling and lubrication at the cutting zone. This reduces heat concentration and prevents premature tool wear.
Recommended for:
Food-grade stainless (304, 316L)
Martensitic stainless (420, 440C)
Austenitic and duplex grades
Try our Carbide Twist Drills for Stainless Steel with Coolant Holes
Titanium alloys are lightweight but extremely tough, with low thermal conductivity and high chemical reactivity at elevated temperatures. They are also prone to chip adhesion and workpiece deformation if coolant is not properly applied.
Using internal coolant drills helps to:
Lower surface temperatures
Prevent chemical bonding with the tool
Reduce galling and burr formation
Recommended for:
Aerospace titanium parts
Medical implant machining
Precision titanium components
Did you know? According to a 2022 study in Journal of Materials Processing Technology, internal coolant drills improved tool life by up to 60% when drilling Ti-6Al-4V compared to standard carbide drills.
Tool steels like H13, D2, and SKD11 become very abrasive once heat-treated. They generate excessive heat and wear conventional drills rapidly, especially when hole depth exceeds 3×D.
Internal coolant systems allow high-pressure fluid to reach the cutting edge, dramatically reducing friction and improving dimensional control.
Recommended for:
Mold & die industries
Injection mold base drilling
Automotive stamping tools
Explore Coolant-Through Carbide Drills for Hardened Steels
These “superalloys” are used in high-temperature and high-stress environments (aerospace turbines, chemical reactors). They are extremely heat-resistant but difficult to machine — often causing thermal damage and excessive tool wear.
Internal coolant helps:
Maintain cutting edge temperature
Flush out hard, abrasive chips
Improve surface finish and reduce microcracks
Recommended for:
Jet engine parts (Inconel 718, 625)
Chemical processing equipment
These materials are known for toughness and strain hardening. Drilling them without proper cooling often results in vibration, chip welding, and breakage.
Coolant-through carbide drills reduce vibration and maintain cutting fluid access even in deep, narrow holes.
Recommended for:
Mining, energy sector parts
Structural and wear-resistant components
Yes, but it depends. Aluminum is easier to machine and often doesn't require internal coolant unless:
You're drilling deep holes (>10×D)
You're machining aluminum alloys with high Si content (abrasive)
In most shallow applications, external coolant is sufficient.
| Material | Internal Coolant Recommended? | Notes |
|---|---|---|
| Stainless Steel | ✅ Strongly recommended | Prevents BUE and overheating |
| Titanium Alloys | ✅ Essential | Avoids thermal damage and tool bonding |
| Hardened Steels | ✅ | Improves tool life and accuracy |
| Inconel/Nickel Alloys | ✅ | For superalloy resistance |
| Cast Iron | ❌ Not necessary | Chips break naturally, low heat |
| Aluminum | ⚠️ Conditional | Needed only for deep holes or certain alloys |
Look for coolant-through carbide drills with:
Helical or straight internal channels
135° split point geometry
High-performance coatings (TiAlN, AlTiN)
H6 tolerance for high precision
Need help choosing the right drill? Check out our Full Range of Coolant Hole Carbide Drills for CNC applications in demanding metals.
Coolant hole carbide drill bits are an investment — but for hard metals, heat-sensitive alloys, and deep-hole CNC jobs, they pay off in tool life, part quality, and process stability.
Whether you're in aerospace, medical, mold-making, or general machining, using the right drill for the right material makes a measurable difference.
Contact our experts today for a free quote or technical consultation.