Air Grinders

Air grinders – also known as pneumatic grinders – are versatile, high-speed tools powered by compressed air and used for grinding, cutting, deburring, polishing, and surface preparation tasks. They’re a staple in engineering workshops, automotive body shops, metal fabrication environments, and construction settings where precision, power, and continuous use are essential.

At Pipestock, we stock a carefully selected range of high-performance air grinders, including die grinders, angle grinders, and straight grinders, designed for professional use across a variety of materials. When paired with the correct accessories and a suitable air compressor, these tools offer outstanding speed, control, and reliability.

An air grinder is a handheld pneumatic tool that uses compressed air to power a high-speed rotary motion for material removal. It functions in a similar way to electric grinders but is powered by an external air compressor rather than an onboard motor. The term can apply to several tool types, including:

• Die grinders: For precision grinding, porting, and polishing
• Angle grinders: For heavy-duty cutting, grinding, and sanding
• Straight grinders: For extended reach into tight spaces

Air grinders are commonly used on metal, plastic, stone, and wood and are highly favoured in professional workshops for their lightweight design, long run-times, and minimal overheating during continuous use.

Using an air grinder correctly is essential for safety, tool longevity, and job quality. Improper use can lead to injury, while neglecting maintenance can cause tool failure or reduced performance.

• Choose the right tool: Select between a die grinder, angle grinder, or straight grinder based on the task.
• Connect to compressor: Use a secure airline and ensure pressure is set according to the manufacturer's guidance (usually 90 PSI)
• Check attachments: Install the correct grinding, cutting or sanding accessory. Ensure it’s rated for the tool’s RPM.
• Secure your workpiece: Use clamps or a vice to prevent movement.
• Wear Suitable PPE: Safety glasses, gloves, and hearing protection are essential. For cutting or grinding metal, a face shield is also recommended.
• Start the tool: Hold firmly with both hands if possible. Press the trigger gradually and begin working the tool over the material using light pressure.
• Maintain control: Avoid forcing the tool. Let the high-speed rotation do the work.
• Shut off and disconnect: When finished, release the trigger, disconnect the airline, and store the tool safely.

Air grinders work by converting compressed air pressure into mechanical rotation using an internal rotary vane motor. When the tool’s trigger or lever is pressed:

1. Air enters the motor housing via the inlet port.

2. The air expands inside the internal motor, spinning it.

3. This spinning motion drives the tool’s output shaft, which in turn spins the grinding attachment.

4. Releasing the trigger shuts off the air flow, stopping the tool.

Most air grinders are designed to run at 90 PSI (6.2 bar) and spin at 10,000 to 25,000 RPM, depending on the tool type and intended use. Speed and torque can be controlled using a variable-speed trigger or by adjusting the airline regulator.

Proper maintenance keeps your air grinder operating safely and efficiently, especially under regular use. Pneumatic grinders are simple in design, but neglect can lead to wear, seizing, or unsafe operation.

• Daily oiling: Use pneumatic air tool oil (such as ISO 22) before and after use. Add a few drops into the air inlet to lubricate internal parts. Alternatively, use an in-line lubricator or filter-regulator-lubricator unit to maintain clean and lubricated airflow.
• Check air lines: Ensure hoses are free from leaks, kinks, and moisture. This is also vital to ensure user safety.
• Drain compressors daily: Prevent water vapour from entering and corroding the tool, as well as rusting the compressor tank.
• Store properly: Keep the tool in a dry place and ideally in a case when not in use.
• Inspect discs and burrs: Check for wear, cracks or imbalance. Replace if necessary.
• Grease internal gears: Use manufacturer-approved lubricant when required.