Combustion Disc Cutters

A petrol handheld power cutter is driven by a two-stroke petrol engine usually rated 4–6 hp (about 3–5 kW) and needs no mains power, which suits sites in the field. An electric cutter needs a 230 V socket, while a cordless one relies on a charged battery that typically lasts several to a dozen minutes of cutting. Both those drives run with no exhaust fumes and quieter operation.

A petrol handheld power cutter takes diamond blades for mineral materials — concrete, asphalt and paving blocks — and abrasive (corundum) blades for steel and rebar. Diamond blades are usually 300–400 mm and cut wet, using about 0.5–1 litre of water per minute, cutting dust by more than 90%. Abrasive blades run dry only and wear faster.

A typical petrol handheld power cutter for concrete and asphalt has a two-stroke engine rated 4–6 hp (about 3–5 kW). Lighter 300–350 mm blade models deliver about 4–5 hp, while 400 mm units for reinforced concrete run about 6 hp. Higher power means steadier revs but more weight, reaching 9–11 kg without a blade.

A concrete cutter runs a diamond blade whose segments need water cooling at about 0.5–1 litre per minute. A steel cutter uses an abrasive (corundum) blade that cuts dry only and wears many times faster than a diamond one. The same petrol handheld power cutter, with a 300–350 mm blade for example, handles both materials — you only need to swap the blade.

Feeding water to the diamond blade on a petrol handheld power cutter cuts dust by more than 90% and extends the blade's working life. Most models have a spigot and valve for a hose or a pressurised tank, using water at about 0.5–1 litre per minute. Dry cutting is possible in short passes with cooling breaks, but it raises far more dust, so water or dust extraction is recommended indoors.

Cutting depth follows from blade diameter — roughly the diameter divided by about 2.8, since part of the blade hides inside the guard. A 300 mm blade gives a depth of about 100 mm, a 350 mm blade about 125 mm, and a 400 mm blade up to about 145 mm. A 300 mm blade is enough for slabs and paving blocks; thick reinforced concrete needs a 350–400 mm blade and a 5–6 hp engine.

The price of a professional-grade petrol handheld power cutter depends mainly on engine power and blade diameter — 300–350 mm, 4–5 hp models usually cost less than 400 mm, 6 hp units for reinforced concrete. Running costs are also shaped by diamond blades, worn out after a few hundred metres of cutting, plus the drive belt and air filter. Current prices are on the product pages.

Clean the air filter every few to a dozen hours of work, more often in dusty conditions, since a clogged filter cuts power and raises fuel use. Replace the spark plug after about 100–150 hours. The engine runs on a petrol-oil mix in the ratio given by the manufacturer's manual (typically 1:25–1:50), and the drive belt is checked every few dozen hours for wear.