How to Cut Hardened Steel Using an Angle Grinder

Hardened steel is known for its exceptional durability and strength, making it a popular choice for a wide range of applications, from construction and automotive to crafting and DIY projects. However, cutting through hardened steel can be a challenging task, even for experienced craftsmen. One effective and versatile tool for this purpose is the angle grinder. In this article, we will explore the techniques and tips you need to know to cut hardened steel with an angle grinder safely and efficiently.


Understanding the Angle Grinder


Before we dive into the specifics of cutting hardened steel, it’s essential to understand the angle grinder and its components.

  1. Angle Grinder Components

An angle grinder consists of the following key components:

Motor: The motor powers the grinder and determines its performance. Angle grinders come in various sizes and power ratings, typically measured in watts. For cutting hardened steel, you’ll need an angle grinder with a higher wattage.

Grinding Wheel or Cutting Wheel: The choice of wheel is crucial when working with hardened steel. Grinding wheels are designed for grinding and shaping, while cutting wheels are specifically designed for cutting through metal. Ensure you have a cutting wheel for hardened steel.

Guard: The guard is a safety feature that covers the wheel and protects the user from sparks and debris. It’s adjustable and can be rotated to different positions depending on the cutting angle.

Handle: The handle provides stability and control when operating the angle grinder. Always use both hands to maintain control and minimize the risk of accidents

Locking Nut and Wrench: These are used to secure and tighten the wheel onto the grinder. Make sure the wheel is correctly installed and tightened before use.

  1. Safety Precautions

Safety should always be your top priority when working with an angle grinder, especially when cutting hardened steel. Here are some essential safety precautions to follow:

Wear appropriate safety gear: This includes safety goggles, hearing protection, a dust mask or respirator, gloves, and a long-sleeved shirt to protect your arms from sparks.

Secure your workpiece: Ensure the piece you’re cutting is securely clamped or held in place. This prevents it from moving during the cutting process.

Work in a well-ventilated area: Cutting hardened steel generates a significant amount of dust and sparks. Make sure you’re in a space with good ventilation to reduce the risk of inhaling harmful fumes.

Inspect your equipment: Before starting, check the angle grinder, wheel, and accessories for any damage or wear. Replace any damaged parts immediately.

Maintain a firm grip: Hold the angle grinder with both hands and maintain a firm grip at all times. Keep a safe distance from the wheel.

Follow manufacturer’s guidelines: Read and follow the instructions provided by the manufacturer for your specific angle grinder model.


Choosing the Right Cutting Wheel

Selecting the appropriate cutting wheel is critical when cutting hardened steel. The wrong wheel can lead to inefficient cutting, excessive wear, and potential safety hazards. Here are some factors to consider:

  1. Material Compatibility

Ensure that the cutting wheel you choose is designed for cutting hardened steel. Look for labels or markings on the wheel that specify its compatibility with metal or steel. Using a wheel not intended for steel can result in accidents or damage to the wheel.

  1. Wheel Size

Angle grinder cutting wheels come in various sizes, typically ranging from 4 to 9 inches in diameter. Choose a size that is suitable for your project and the available space. Larger wheels allow for deeper cuts, but they may be challenging to maneuver in tight spaces.

  1. Wheel Thickness

The thickness of the cutting wheel also plays a role in its cutting efficiency. Thicker cutting wheels can withstand more lateral pressure, making them suitable for heavy-duty cutting. However, thinner cutting wheels create less friction and generate fewer sparks. Choose a wheel thickness that matches your specific cutting needs.


Preparing for the Cut

Once you’ve selected the right cutting wheel, it’s time to prepare for the cut. Proper preparation ensures a smooth and safe cutting process.

  1. Mark Your Cutting Line

Use a marker, chalk, or scribe to mark the precise cutting line on the hardened steel. This will serve as your guide during the cutting process and help you achieve the desired cut.

  1. Secure the Workpiece

Place the hardened steel workpiece on a stable surface or clamp it securely to a workbench. Ensure that the piece is firmly held in place to prevent movement while cutting.

  1. Adjust the Angle Grinder

Before turning on the angle grinder, adjust the guard to the desired position. The guard should cover the wheel but allow enough clearance for the material being cut. Adjust the handle to a comfortable and stable grip.

  1. Install the Cutting Wheel

Use the provided locking nut and wrench to attach the cutting wheel to the angle grinder’s spindle. Make sure the wheel is correctly centered and tightened securely.


Cutting Hardened Steel

With your angle grinder properly prepared and safety precautions in place, it’s time to cut the hardened steel. Follow these steps for a successful cut:

  1. Position Yourself

Stand in a stable and balanced position with your feet shoulder-width apart. Hold the angle grinder with both hands, ensuring a firm grip on the handle and the auxiliary handle (if equipped).

  1. Start the Angle Grinder

Before making contact with the steel, start the angle grinder and allow it to reach full speed. This reduces the risk of kickback when you make the initial cut.

  1. Begin Cutting

Gently lower the cutting wheel onto the marked cutting line while maintaining a steady and controlled movement. Apply light pressure to the angle grinder, letting the wheel do the cutting. Avoid forcing or pushing too hard, as this can overheat the wheel and reduce its effectiveness.

  1. Maintain a Steady Pace

Continue moving the angle grinder along the cutting line at a steady pace. Keep the wheel in contact with the steel, but avoid pressing too hard, as this can cause excessive friction and overheating.

  1. Coolant for Cooling

If you’re cutting a large or thick piece of hardened steel, it’s advisable to use a coolant or lubricant to keep the cutting wheel and steel cool. A cutting oil or water-based coolant can help prolong the life of the wheel and improve the quality of the cut. Apply the coolant as needed during the cutting process.

  1. Monitor the Cut

Pay close attention to the progress of the cut. Ensure that the angle grinder stays on the marked cutting line and that the cutting wheel is making steady and even progress through the hardened steel.

  1. Complete the Cut

Once you’ve cut through the hardened steel along the entire marked line, turn off the angle grinder and allow the wheel to come to a complete stop before setting it down.


Post-Cutting Steps

After successfully cutting through the hardened steel, there are a few essential post-cutting steps to follow:

  1. Allow Cooling

Give the cut steel some time to cool down, especially if you used a coolant. Hot steel can be a safety hazard, so exercise caution when handling it immediately after cutting.

  1. Inspect the Cut

Examine the cut surface for any imperfections, burrs, or rough edges. If necessary, use a deburring tool or a sandpaper to smooth out the edges for a clean finish.

  1. Clean the Work Area

Clean up the work area by removing any debris, metal shavings, or leftover coolant. Dispose of these materials safely to prevent accidents or contamination.



Cutting hardened steel with an angle grinder is a practical skill that can open up a world of possibilities for DIY enthusiasts and professionals alike. By selecting the right cutting wheel, following safety precautions, and employing proper cutting techniques, you can achieve precise and efficient cuts in hardened steel. Remember to prioritize safety at all times, and practice your skills on scrap pieces before tackling more significant projects. With practice and experience, you’ll become proficient in cutting hardened steel with an angle grinder, expanding your capabilities and boosting your confidence in metalworking projects.