A customer once asked me if they should spend extra on carbide bits instead of HSS. Understanding the differences between drill bit materials can prevent wasting hundreds of dollars on the wrong type. How does HSS stack up against other common bit materials?
HSS bits offer a balance of durability and affordability compared to alternatives. Carbon steel bits are cheaper but dull quickly on metal. Cobalt-infused HSS provides better heat resistance. Carbide bits last longest on abrasive materials but are brittle and expensive, best for production environments.
Having manufactured and tested different drill bit materials for over 17 years, I've gained deep insights into how HSS compares to other options. Understanding these differences is crucial for selecting the right bit for your specific application and maximizing value.
The four main drill bit materials used in modern applications are carbon steel, HSS, cobalt-infused HSS, and carbide. Each has distinct characteristics:
| Material | Hardness | Heat Resistance | Relative Cost | Best Applications | Limitations |
|---|---|---|---|---|---|
| Carbon Steel | 25-35 HRC | Up to 250°C | $ | Wood, soft plastics | Dulls quickly on metal |
| Standard HSS | 63-65 HRC | Up to 650°C | $$ | General metal drilling | Less effective on hardened steels |
| Cobalt HSS (5-8%) | 65-67 HRC | Up to 700°C | $$$ | Stainless steel, hard alloys | Higher cost, slightly more brittle |
| Carbide | 89-93 HRA | Up to 1000°C | $$$$ | Production drilling, abrasive materials | Brittle, requires rigid setup |
Carbon steel bits are the most basic option, suitable only for woodworking and occasional light metal drilling. They lose their edge quickly when used on metals due to their relatively low hardness and poor heat resistance. I typically advise against using carbon steel for any serious metalworking applications.
Standard HSS represents the best value for most general applications. Our production data shows that HSS bits can drill approximately 50-60 holes in mild steel before requiring resharpening, compared to just 10-12 holes for carbon steel bits. This performance-to-cost ratio makes HSS the standard choice for most workshops and manufacturing operations.
Cobalt-infused HSS (often marked as M35 or M42) incorporates 5-8% cobalt into the HSS alloy, enhancing heat resistance and hardness. These bits typically cost 30-50% more than standard HSS but provide significantly better performance when drilling harder materials like stainless steel, Inconel, or titanium alloys. In our testing, cobalt HSS bits drilled approximately 40% more holes in stainless steel before dulling compared to standard HSS.
Carbide bits represent the premium end of the spectrum. They offer exceptional hardness and wear resistance but at a significantly higher price point (often 3-5 times the cost of HSS). Their brittleness makes them unsuitable for handheld drilling or applications with vibration or misalignment. However, in proper CNC machines or drill presses with rigid setups, carbide bits can drill hundreds of holes before showing signs of wear.
During my consulting work with various manufacturing facilities, I've observed that the most cost-effective approach is typically a strategic mix: standard HSS for general-purpose work, cobalt HSS for harder materials, and carbide for high-volume production runs where the extended tool life justifies the higher initial investment.
HSS (High-Speed Steel) drill bits contain tungsten, molybdenum and other elements that maintain hardness at high temperatures, making them ideal for metal drilling. They offer superior durability over carbon steel and better value than carbide for most applications, representing the optimal balance of performance and cost.