Quick Answer

To grind concrete with a Makita grinder, fit a diamond cup wheel or trapezoid disc rated for concrete, install the side handle and guard, set the speed (if variable) to the disc's rated range, connect a dust shroud and vacuum, and grind in overlapping passes with the disc flat. A 125 mm Makita grinder with a diamond trapezoid grinding disc handles most concrete grinding jobs. Always use the guard and eye and hearing protection.

Choose the Right Disc

Use a diamond grinding disc rated for concrete: a cup wheel for general material removal and edge work, or a trapezoid disc with segmented diamonds for flatter coverage on floors. Match the disc size to the grinder (125 mm or 180 mm), check the arbor matches, and confirm the disc's maximum RPM is at or above the grinder's no-load speed. For heavy coating removal choose a PCD disc; for smoothing and level spotting use a metal-bond diamond disc. Never fit a wood or metal disc to concrete work.

Fit the Guard, Handle, and Shroud

Mount the guard so it covers the disc at the rear and deflects debris away from you. Fit the side handle firmly; grinding concrete needs two hands for control, and the handle prevents the grinder from twisting on kickback. If you are dry grinding, fit a dust shroud over the guard that seals against the floor and connects to a vacuum; the shroud skirt must sit flat on the surface to capture dust at the source. For wet grinding, fit a water feed adapter and connect a supply.

Set the Speed

On variable-speed Makita grinders, set the dial within the disc's rated range: typically 6 000-8 000 RPM for grinding concrete with a 125 mm disc, and lower for 180 mm discs. Start on the lower end until the disc is seated, then increase as needed. Running a diamond disc too fast on concrete burns the bond and shortens disc life; too slow makes the disc bounce and leave chatter marks. Mark the dial position for concrete work so it is not accidentally changed mid-job.

Connect Dust Control

Dry grinding concrete produces fine silica dust. Connect a HEPA-rated vacuum to the shroud with the correct adapter and a short hose so suction stays strong. Check the seal between shroud and floor before starting; a visible gap means dust escapes. Empty the vacuum before it is half full, because concrete dust packs and reduces airflow. Wear an N95 or better respirator even with the vacuum connected, plus eye protection, gloves, and hearing protection.

Grinding Technique

Hold the grinder with both hands, keep the disc flat against the concrete, and move in overlapping passes. Do not press down hard; the machine's weight is enough, and pressure causes gouges and overheating. Let the disc glide, lift it between passes, and check your work often. For deep material removal, make several passes rather than one heavy pass. On edges, tilt the grinder slightly so only the outer edge of the cup contacts, and keep it moving. Stop and inspect the disc if the motor labours or the surface glazes.

Finishing and Maintenance

After grinding, vacuum the floor and inspect the surface with a straightedge; high spots need more passes, low spots may need a patch. Switch to a finer grit disc or polishing pads to blend the ground area with the surrounding finish. Clean the Makita grinder after use: blow dust out of the vents, remove the disc and store it flat and dry, and wipe the machine body. Check the carbon brushes periodically and replace them when short, and keep the guard and shroud in good condition.

For dependable concrete grinding, equip your machine with a diamond trapezoid grinding disc matched to the concrete hardness.

See the diamond grinding cup wheels to keep every stage of the job running with quality consumables.