ESAn angle grinder is one of the most useful tools on a stone or tile job and one of the most dangerous. It spins a hard, brittle accessory at high speed, and a blade that grabs or fails can cause serious injury in an instant. Most grinder accidents come from a small number of avoidable mistakes, and a simple checklist before every cut removes almost all of them.
Before you pick up the tool
- Check the accessory's maximum RPM against the grinder's no-load speed. The accessory rating must be at least the tool's speed. This is the single most important check - see matching RPM ratings.
- Inspect the accessory for cracks, missing segments, bends and damage. A damaged blade goes in the bin, not on the grinder.
- Check the markings are legible - especially the RPM rating and intended use.
- Fit the guard and make sure it is adjusted to cover as much of the accessory as practical.
- Fit the side handle and check the tool and cable are undamaged.
- Match the bore or thread to the spindle, and confirm the accessory seats flat and true.
Personal protective equipment
- Eye protection - goggles rather than glasses, plus a face shield for cutting where fragments fly.
- Hearing protection - grinders are loud and the exposure is cumulative.
- Dust mask or respirator - cutting stone and concrete produces silica dust; a light mask is not enough.
- Gloves - cut-resistant, though keep them clear of a spinning accessory.
- Workwear - close-fitting, with no loose cuffs or cords to catch.
Preparing the workpiece
- Support and clamp the material so it cannot move or pinch the blade.
- Support both sides of a cut, especially the exit, so the material does not flex and grab.
- Clear the area of people; fragments travel further than expected.
- Know where the power cable is, and keep it clear of the cut.
- Set up water or extraction so dust is controlled from the start.
Cutting safely
- Start the grinder away from the material and let it reach full speed before contact.
- Cut away from your body, and never cut towards yourself.
- Hold the tool with both hands on the body and handle, and keep a stable stance.
- Feed steadily and let the blade cut; forcing it causes kickback and heat.
- Do not twist or steer the blade in the cut - that is how blades grab and shatter.
- Do not reach under the material or put a hand in the line of the cut.
- Switch off and let the blade stop before setting the tool down or reaching near it.
Kickback, and how to avoid it
Kickback happens when the blade binds or catches and the grinder is thrown back at the operator. It is most likely when the blade is pinched by material closing on the cut, when the blade is twisted, or when it is fed too fast. The prevention is to support the workpiece, avoid twisting, feed steadily and stand clear of the kick path. Be especially careful at the end of a cut and when the piece is under any stress.
Safety
Keep the guard fitted at all times, respect the RPM rating, wear full PPE, keep water away from electrical connections with an RCD or GFCI and follow the manufacturer's instructions for the tool and the accessory. Do not remove the guard to make a cut - a cut that cannot be made safely should not be made that way. For blade marking, see reading diamond blade labels, and for the tool side, browse the diamond tool ranges.
Checklist in short
- RPM, accessory condition, guard, handle, PPE - every time.
- Support and clamp the work; support both sides of the cut.
- Feed steadily, never twist, never cut towards yourself.
- Kickback is preventable with support, steady feed and a stable stance.
