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An angle grinder is the most useful tool most people do not own, and the one most likely to hurt you. This answers which to buy, then how not to regret it.

The short answer

Occasional home use — cutting tile, a bolt, light rust removal: a corded 100mm (4") grinder, $52 to $70. Cheap enough to own before you need it.

Regular work: a 100mm from Makita, DeWalt or Bosch around $85 to $90, with a paddle switch and an electric brake.

Site work, or you already own batteries: cordless brushless, so you are not hunting for a socket in a half-built flat.

4-inch or 5-inch?

Singapore runs overwhelmingly on 100mm (4"). Discs are cheaper and everywhere, the tool is lighter, and it fits where a bigger one will not. Cutting depth is around 25mm, which covers tile, rebar, bolts and section.

125mm (5") buys you roughly 30mm of depth and more motor. Worth it if you cut thicker material regularly. For a flat, it is usually more tool than the job needs.

Whatever you choose, discs must match the guard size. You cannot safely run a 125mm disc on a 100mm machine.

Paddle switch or slide switch — this one matters

A paddle switch must be held down. Let go, drop the tool, catch your hand in it — and the motor stops. Many Singapore worksites now require them, and for a home user who uses a grinder twice a year, it is the safer default.

A slide switch stays on until you switch it off. Better for sustained work where holding a paddle is tiring. Less forgiving if the tool binds and jumps.

If you are not sure, buy the paddle.

What else to look for

• Electric brake — stops the disc in seconds rather than letting it spin down. The single feature most worth paying for
• Anti-kickback / soft start — cuts power if the disc jams, and stops the tool lurching on startup
• Toolless guard adjustment — you will move the guard constantly, and if it needs a spanner you will stop bothering, which is how people get hurt
• Weight — you will hold this at arm's length. Half a kilo matters more than the spec sheet suggests

Three to buy

• Cheapest worth owning — Bosch GWS 700, 4", 710W, $52. A real Bosch Professional at an entry price. Fine for occasional work.
• Best value for regular use — Makita GA4030, $88.41. The one most tradesmen here actually own. Reliable, repairable, parts available.
• Safest for an inexperienced user — DeWalt DWE8200PL with deadman switch, $89.99. Releases the moment you do.

See the full grinder range, or try them at our Geylang showroom.

The discs matter more than the grinder

A grinder is a motor that spins whatever you fit to it, so the disc decides the job:

• Cutting discs — thin, for metal or masonry. Never grind with the side of one; they are not made for lateral load and they shatter
• Grinding discs — thick, for removing material and dressing welds
• Diamond blades — for tile, concrete and stone
• Flap discs — for finishing and blending
• Wire cup brushes — for rust, scale and paint

Match the disc to the material, and check the disc's maximum RPM is at least your grinder's speed.

Safety, briefly and seriously

More people are injured by angle grinders than by any other power tool. Three rules cover most of it:

Goggles, not glasses. Grinders throw sparks and particles from every direction, and a disc that shatters sends fragments sideways.

Keep the guard on. It exists to put metal between you and a disintegrating disc. Removing it to reach something is how people lose fingers.

Let the tool reach full speed before it touches the work, and never start a cut with the disc already loaded.

Working indoors on tile or concrete? Use dust extraction. Silica dust is a genuine long-term health hazard, not just a mess.

Need discs as well? See diamond blades and core bits for tile and concrete, wire brushes for rust, and abrasives for finishing.