Makita GA9020 110V Angle Grinder 230mm (9")

Who is this for

The Makita GA9020 110V is used primarily by steel fixers, groundworkers, fabricators, and site operatives on UK construction sites where 110V reduced low voltage supply is the standard working practice under HSG107 guidance. It is suited to any professional requiring a large-wheel grinder for sustained grinding, cutting, and surface preparation tasks on metal, concrete, and stone in a site environment. It is equally relevant to utilities and civils operatives working on infrastructure projects where 110V tool compliance is a site rule rather than a preference.

Typical applications

• Grinding and dressing welds on structural steelwork during fabrication and on-site steel erection.

• Cutting rebar, steel plate, and structural sections to length during reinforced concrete and groundwork operations.

• Surface preparation of concrete slabs, steel surfaces, and masonry prior to coating, overlay, or further treatment.

• Cutting concrete, block, and stone during civils, drainage, and groundwork operations on construction sites.

• Removing rust, mill scale, and surface contamination from structural steel prior to welding or protective coating application.

• Disc sanding and surface finishing on metal fabrication and site metalwork tasks.

• Cutting and shaping stone and masonry materials during groundwork, landscaping, and civils finishing work.

How to use

Step 1: Confirm the supply voltage is 110V. This tool is rated 110V only and must not be connected to a 230V or 240V mains supply. A 32A supply is recommended; 16A is acceptable but may limit sustained performance under heavy load.

Step 2: A plug is not supplied with this tool. Fit the appropriate 110V plug before connecting to site supply. Ensure all connections comply with site electrical safety requirements.

Step 3: Install the side handle and wheel guard before use. The wheel guard is mandatory for all grinding, cutting, and sanding operations. Never operate without the guard fitted.

Step 4: Select the correct disc or wheel for the intended application. Check the disc's rated speed is at least equal to the grinder's no-load speed of 6,600 rpm. Inspect the disc for cracks, chips, or damage before fitting. Do not fit a damaged disc.

Step 5: Mount the disc using the inner flange, disc, and lock nut in the correct order. Press the spindle lock button and tighten the lock nut firmly with the supplied lock nut wrench. Release the spindle lock before starting.

Step 6: Start the grinder before bringing the disc into contact with the workpiece. Never start with the disc already in contact with the material.

Step 7: Hold the tool firmly with one hand on the rear handle and the other on the side handle. Keep the disc edge at approximately 15 degrees to the workpiece surface for grinding operations.

Step 8: After use, switch off and wait for the disc to come to a complete stop before setting the tool down.

Common mistakes

• Connecting to 230V supply: This is a 110V tool. Connecting to a standard 230V mains socket will destroy the tool and creates a serious electrical hazard. Always confirm supply voltage before connecting.

• Operating without a wheel guard: The wheel guard is not optional. Operating without it exposes the operator to disc fragments, sparks, and loss-of-control risk. Refit the guard before every use.

• Using an undersized supply: Running a 2,000W 110V tool on a 16A supply under heavy continuous load can cause circuit protection to trip. A 32A supply is the recommended specification for sustained site use.

• Fitting a damaged or incorrect disc: A cracked, chipped, or incorrectly rated disc can shatter at speed. Inspect every disc before fitting and confirm its maximum rated speed meets or exceeds 6,600 rpm.

• Side grinding with a cut-off wheel: Cut-off wheels are designed for peripheral cutting only. Applying lateral pressure to a cut-off wheel causes it to shatter. Use a grinding disc for surface grinding operations.

• Neglecting air vent cleaning: The motor fan draws dust into the housing. On site, dust and metal particle build-up in the air vents accelerates motor wear even with labyrinth protection. Clean the vents regularly with compressed air.

Safety

This tool operates at 110V and must only be connected to a correctly rated 110V site supply. Do not connect to 230V or 240V under any circumstances. A plug is not supplied; fitting must be carried out by a competent person in accordance with the Electricity at Work Regulations 1989. Always fit the wheel guard before operation. Wear face protection, eye protection, hearing protection, and appropriate gloves for all grinding and cutting operations. Do not use liquid coolants with this tool. Do not use this tool on materials containing asbestos. The disc continues to rotate after switching off; do not set the tool down until the disc has come to a complete stop. If the disc binds during cutting, switch off immediately and hold the tool still until the disc stops before investigating.

Maintenance

Clean air vents regularly using dry compressed air to prevent dust and metal particle build-up. Do not use solvents, petrol, thinners, or alcohol on any part of the tool as these cause discolouration, deformation, and cracking of housing components. Carbon brushes are externally accessible; inspect at regular intervals and replace both brushes simultaneously when the resin insulating tip becomes exposed. Use only identical replacement carbon brushes. For all other repairs and adjustments, use a Makita authorised service centre. Inspect the disc, inner flange, spindle, and lock nut before each use and replace any damaged components before operating.