Angle Grinder Guide: Choosing and Using Safely

Angle grinders are among the most versatile and most dangerous tools on site. Understanding what they can do - and their limitations - helps you work safely and effectively.

Size Matters

Angle grinders come in different disc sizes:

• 115mm (4.5"): Light work, tight spaces, one-handed operation
• 125mm (5"): Good all-rounder, most common size
• 230mm (9"): Heavy cutting, deeper capacity, two-handed operation

Bigger isn't always better. A 230mm grinder cuts deeper but is heavier, harder to control, and more dangerous if things go wrong. Choose the smallest size that does the job.

Disc Selection

Different discs for different tasks:

• Cutting discs: Thin (1-1.6mm), for clean cuts in metal
• Grinding discs: Thicker, for removing material and shaping
• Flap discs: For finishing and blending welds
• Diamond blades: For cutting masonry, concrete, tile
• Wire brushes: For rust removal and surface preparation

Safety Non-Negotiables

Angle grinders spin fast - typically 10,000+ RPM. At those speeds, disc failure sends fragments flying like shrapnel. Always:

• Wear safety glasses or a face shield
• Use ear protection
• Check disc ratings match the grinder speed
• Never remove the guard
• Let the disc reach full speed before cutting
• Keep bystanders clear of the work area

Cutting Technique

Let the disc do the work. Forcing it generates heat, wears the disc faster, and increases the chance of kickback. Keep a firm grip with both hands on larger grinders. Cut with the grain of the material where possible.

Corded vs Cordless

Modern cordless grinders from brands like DeWalt and Makita rival corded performance. The freedom from cables improves safety and convenience. Battery runtime has improved significantly - a 5Ah battery handles most daily tasks.

Maintenance

Keep vents clear of dust. Check the disc guard moves freely. Inspect discs before use - cracks or chips mean immediate replacement. Store in a case to protect against damage.