Choosing the Right Industrial Drill Bit for Metal

Drilling through metal requires more than just a powerful drill. The bit you choose can make the difference between a clean, accurate hole and a costly mistake. Whether you’re fabricating stainless steel pipe, assembling structural frames, or maintaining heavy-duty machinery, selecting the right drill bit ensures better results, faster work, and longer tool life.

At BC Industrial Supply, we understand the demands of professional metalworking and carry a wide range of high-performance drill bits for ferrous and non-ferrous metals. We also offer expert guidance, fast nationwide shipping, and tool repair services to keep your operations running smoothly.

This guide covers how to choose the right industrial drill bit for metal, based on the material you’re drilling, the task at hand, and the performance you need.

Understanding Metal Types and Their Challenges

Not all metals respond the same way to drilling. Some are soft and pliable, while others are tough and heat-resistant. Knowing the type of metal you’re working with is the first step in selecting the proper bit.

Mild Steel and Low Carbon Steel

These are among the most common metals used in industrial applications. They’re relatively soft, making them easier to drill. High-speed steel (HSS) drill bits typically perform well here, but bit geometry and coating still play a role in performance and longevity.

Stainless Steel

This alloy resists corrosion and adds strength, but it’s much harder than mild steel. Stainless tends to work-harden when drilled, which can cause rapid dulling of the bit. Cobalt drill bits or titanium-coated HSS bits are better suited for this application.

Aluminum and Other Non-Ferrous Metals

Aluminum is lightweight and soft, but it has a tendency to gum up drill flutes. Using a sharp HSS bit with a parabolic flute or a polished finish helps clear chips and maintain speed. Brass and copper require similar considerations but generally offer less resistance.

Hardened Steel and Tool Steel

These materials are designed to resist deformation, which also makes them difficult to drill. Cobalt and carbide drill bits offer the best results here. Slower speeds, steady pressure, and frequent lubrication are essential to prevent overheating.

Drill Bit Materials and Their Applications

The material of the drill bit determines how it handles heat, pressure, and wear. Matching the bit material to the job saves time and extends tool life.

High-Speed Steel (HSS)

HSS bits are an economical option for general metalworking. They offer decent hardness and heat resistance, making them suitable for mild steel, aluminum, brass, and similar materials. However, HSS bits wear quickly when used on harder alloys.

Cobalt (M35 or M42)

Cobalt bits are made from an alloy with 5–8% cobalt added to HSS. This makes them more brittle but significantly more heat-resistant and durable. They excel in stainless steel, cast iron, and other hard metals. Cobalt bits can often be sharpened multiple times without losing effectiveness.

Carbide

Solid carbide or carbide-tipped bits are among the hardest and most wear-resistant. They’re ideal for hardened steel, high-speed machining, and repetitive production work. However, they are more expensive and prone to breaking under improper handling or unstable drilling conditions.

Choosing the Right Bit Geometry

Bit geometry affects how the tool cuts, removes chips, and manages heat. Choosing the right point angle, flute design, and coating ensures smoother operation and less downtime.

Point Angle

A 118° point angle is standard and works well for softer metals. For harder materials, a 135° split point is preferred. It reduces walking on the surface and requires less force, which helps prevent overheating and breakage.

Flute Design

Flutes are the channels that carry chips away from the hole. Standard flutes work for general use, but specialized geometries—such as parabolic or wide flutes—help reduce clogging in aluminum and other soft metals. Deep-hole drilling often requires extended-length flutes for effective chip evacuation.

Coatings

Coated bits last longer by reducing friction and heat. Common coatings include:

Black Oxide: Provides mild corrosion resistance and reduces chip welding in softer metals.

Titanium Nitride (TiN): Gold in color, TiN increases wear resistance and is suitable for a wide range of metals.

Titanium Aluminum Nitride (TiAlN): With superior heat resistance, TiAlN is a good choice for stainless steel and high-speed drilling.

When to Use Lubricants or Coolants

Drilling generates friction, especially in metals. Without proper cooling, bits overheat, dull prematurely, and can even warp. Applying cutting fluid or coolant extends tool life and improves hole quality.

For general steel or aluminum, a standard cutting oil works well. When drilling stainless steel or hard alloys, use a high-pressure coolant or a specialized lubricant to prevent work-hardening. Some machines use flood coolant systems, but handheld applications benefit from tapping fluids applied directly to the bit and workpiece.

In production settings, consider mist or through-tool coolant systems for continuous drilling. Regularly clear chips to prevent re-cutting and heat build-up.

Matching Drill Bit Size and Type to the Task

Industrial metalworking involves a wide variety of applications—each with unique requirements for precision, durability, and hole quality.

Pilot Holes and Step Drilling

When working with thick metal, start with a smaller pilot hole to reduce stress on the bit and improve accuracy. Step drilling also helps when a large-diameter hole is needed.

Countersinking and Spot Drilling

Use a spot drill to create a precise starting point before using a twist drill. This reduces walking and ensures better hole alignment. For fastener applications, countersinking tools add a beveled edge for flush installation.

Twist Drills vs. Specialty Bits

Twist drills are the go-to for most metalworking jobs, but specialized bits may offer better performance. For example, annular cutters create cleaner holes with less effort, especially in structural steel or pipe work. Step bits allow drilling multiple hole sizes in thin sheet metal without changing tools.

Drilling Thin Metal or Sheet Stock

Thin materials are prone to tearing or deforming. Use a step drill or a bit with a flatter point angle to prevent grabbing and ensure clean holes. Clamping the workpiece tightly prevents vibration and misalignment.

Safety and Best Practices

Proper technique matters as much as the tool itself. Always wear safety glasses and gloves when drilling metal. Use a secure vise or clamp to stabilize the workpiece. Let the bit do the work—applying too much force can cause breakage or damage to the surface.

Pay attention to the RPM settings on your drill. Softer metals allow higher speeds, while harder metals require slower RPMs. If the bit starts smoking or discoloring, stop immediately, let it cool, and consider changing the bit or using a better lubricant.

Frequent inspection helps spot wear before it leads to poor results or safety risks. Replace dull bits or resharpen as needed.

Final Thoughts

Choosing the right drill bit for metal isn’t just about grabbing the nearest tool off the shelf. It’s about matching the bit’s material, design, and coating to the specific metal, application, and equipment being used. A bit that works perfectly on aluminum might fail quickly on stainless steel.

At BC Industrial Supply, we help professionals across manufacturing, maintenance, and construction find the right tools for the job. Whether you need high-performance cobalt bits, carbide-tipped options, or just advice on what works best for your next project, our team is here to help you make it happen.

The right drill bit saves time, reduces waste, and protects your tools and materials. Choose wisely—and drill with confidence.