Why Do My Drill Bits Keep Breaking? Try Carbide Instead

By Senior Application Engineer, Amony Cutting Tools    ·    Published: July  30,  2025     ·     Views: 1040

If you’ve ever snapped a drill bit mid-job, you’re not alone. Whether you’re working on steel, aluminum, or even plastic, broken drill bits are a common—and frustrating—problem. You waste time, scrap parts, and rack up tooling costs.

But here’s the good news: it’s not always operator error. In many cases, the real issue is using the wrong type of drill bit for the material or application. That’s where carbide drill bits come in.

Let’s break down the most common reasons your drill bits might be failing—and why switching to carbide could save you time, money, and production headaches.


Common Reasons Drill Bits Keep Breaking

Before we jump into solutions, it helps to understand what’s going wrong. Here are the top causes:

1. Using HSS Bits on Hard Materials

High-speed steel (HSS) bits are affordable and easy to sharpen, but they’re not designed for hard materials like stainless steel, titanium, or cast iron. If you’re drilling into these tougher metals, HSS bits will dull quickly and are likely to break under heat or pressure.

2. Incorrect Feed and Speed Settings

Running your bits too fast, too slow, or without the proper chip load can cause overheating, vibration, and premature failure. Drilling needs a balanced feed rate and RPM—especially with metals.

3. Poor Tool Holding or Setup Rigidity

Even a top-tier drill bit won’t survive long if your machine has vibration or the tool isn't properly secured. A wobbly setup increases side load on the bit, leading to fractures and micro-cracks that cause breakage.

4. Lack of Coolant or Lubrication

Drilling metal without cutting fluid is a recipe for overheating. Excessive heat softens HSS bits and weakens their edge, especially in deep-hole drilling or continuous production.

5. Incorrect Drill Geometry

Using the wrong point angle or flute design for the material can affect how chips evacuate and how much force is applied. Too much thrust = broken bit.


Why Carbide Drill Bits Are the Smarter Alternative

So, how does carbide fix these issues? Carbide drill bits—made from tungsten carbide, a hard and heat-resistant compound—are engineered to handle more demanding applications.

Here’s why more professionals are switching to carbide:

1. Superior Hardness and Wear Resistance

Carbide is significantly harder than HSS or cobalt, which means it resists dulling and holds a sharp edge longer. This directly translates to longer tool life and fewer replacements.

2. Handles Heat Better

Because carbide has a much higher melting point, it can withstand the heat of high-speed drilling—especially useful in dry or MQL machining. Less heat deformation = more accurate holes.

3. Excellent for Tough Materials

Need to drill stainless steel, hardened alloys, or cast iron? Carbide excels where HSS fails. It maintains cutting performance even in high-pressure or abrasive environments.

4. High Precision, Consistent Results

With solid carbide drills, you can expect tight tolerances and clean holes even in continuous production. That consistency helps reduce rework and improves part quality.


Carbide Drill Bit Use Cases

MaterialRecommended Bit Type
Carbon SteelCoated carbide drills
Stainless SteelSolid carbide or coolant-through
AluminumUncoated or DLC-coated carbide drills
Titanium AlloysMulti-flute carbide drills with AlTiN/AlCrN coatings
Cast IronCarbide-tipped or solid carbide drills
Plastics/CompositesPolished carbide drills for clean cutting

Thinking of Upgrading? Here’s What to Consider

  • Machine Rigidity: Carbide drills perform best on CNCs or rigid setups. Avoid them on hand drills or unstable setups—they’re brittle compared to HSS.

  • Coolant Flow: If you’re drilling deep or hard materials, look for carbide drills with internal coolant holes.

  • Coatings: Coatings like TiAlN, AlCrN, or diamond-like carbon (DLC) improve wear life and reduce chip welding.


Final Thoughts: Stop Breaking Bits, Start Drilling Smarter

Broken bits aren’t just annoying—they’re costly. If you’re dealing with frequent tool breakage, consider upgrading to carbide drill bits for longer life, better hole quality, and reduced downtime.

At Amony, we offer a full range of solid carbide drill bits and indexable carbide drills for metalworking professionals. From general-purpose machining to aerospace-grade drilling, our carbide solutions are factory-direct—engineered for performance and priced for value.

Contact us for custom sizes, coatings, or distributor inquiries.

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