Buying a concrete cutter looks simple until you actually sit down to do it. One supplier tells you a 350 mm blade is enough. Another says you need 500 mm or you’ll regret it. A third one throws horsepower numbers at you and expects you to be impressed. Meanwhile you’re just trying to work out one thing – will this machine cut what my site needs it to cut, day after day, without dying on me in month four?
At MKG, we manufacture concrete cutters and we also sell them to contractors across India, so we hear the same three questions on almost every call: how big should the blade be, how deep will it actually cut, and how much engine do I really need? This guide answers those three, in plain language, and then covers the handful of things people forget to ask about until the machine is already on site.
Let’s start with the part most buyers get backwards.
Don't start with the machine. Start with the cut.
Here’s the mistake we see most often. A contractor decides on a budget, looks at machines in that range, and then hopes whatever he buys will handle the work.
Flip it. Write down three things first:
- What are you cutting? Fresh concrete, cured concrete, asphalt, or a mix of all three across different sites?
- How thick is it, and how deep does the cut need to go? A 150 mm slab where you only need a control joint is a completely different job from a 250 mm road panel you need to cut right through.
- How often? Two hours a week, or six hours a day for the next eight months?
Those three answers decide your blade size, your depth requirement and your engine – in that order. Get them written down and the rest of this guide becomes a simple matching exercise instead of a guessing game.
Blade Size: what the diameter actually buys you
The blade diameter is the number everyone quotes, and it’s the number most people misread.
A 350 mm blade does not give you 175 mm of cutting depth. That catches out a lot of first-time buyers. The blade isn’t a floating disc – a good chunk of it is swallowed by the arbor shaft, the mounting flanges and the blade guard. What’s left sticking out below the machine is your usable depth, and as a working rule that’s roughly one-third of the blade diameter, not half.
So in practice:
- A 350 mm (12″/14″) blade gives you somewhere around 90–135 mm of usable depth
- A 500 mm (16″/20″) blade opens that up to roughly 170–270 mm
That’s exactly the spread you’ll see between our two models, and it’s why the blade size question is really a depth question in disguise.
Two more things about diameter that matter on site:
Your machine has a maximum blade rating – respect it. You cannot fit a bigger blade to a smaller cutter and expect extra depth. The guard won’t clear it, the shaft speed will be wrong for that diameter, and the blade will run outside its safe RPM. This is one of the genuinely dangerous shortcuts in concrete cutting.
The arbor hole has to match. The centre hole on the blade must sit flush on the shaft with no play. A blade that wobbles even slightly will cut wide, wander off the line and wear unevenly.
Cutting Depth: how deep do you genuinely need to go?
Here’s the good news – most buyers need less depth than they think, and a few need considerably more.
If you’re cutting control joints or expansion joints, you don’t cut through the slab at all. Standard practice is to cut roughly a quarter to a third of the slab thickness, timed within the first several hours after finishing so the concrete cracks where you want it to instead of where it feels like it. On a 150 mm floor slab, that’s a 40–50 mm cut. A 350 mm-blade machine handles this comfortably all day long.
If you’re cutting right through – road panels, slab removal, controlled demolition – you need the full thickness plus a little margin, because the blade doesn’t cut perfectly square at the very bottom of the arc. On a 200 mm road section, budget for 220 mm or so of capacity, not exactly 200 mm.
And if you’re cutting deeper than your machine’s rated depth, you go in stages. Two or three passes, each 40–60 mm deeper than the last, is standard practice and honestly it’s better for the blade and the engine than trying to force a single deep pass. A machine being pushed to its absolute depth limit on every single cut is a machine that will need service far sooner than one working at 70% of its capability.
That last point is the buying lesson: size your cutter so your typical job sits comfortably inside its range, not at the edge of it. The occasional deep cut can be handled in passes. The everyday cut shouldn’t be a struggle.
Also pay attention to how depth is set, not just how much of it there is. A handle-rotation mechanism lets you dial in depth in fine increments, which matters more than it sounds — precise, repeatable depth control is what keeps joint cutting consistent across a large floor, and it stops an operator guessing halfway through a shift.
Engine Power: the spec that decides whether the machine copes or complains
Engine power is where blade size and cutting depth come together. A bigger blade cutting deeper material needs more torque at the shaft – that’s just physics. Under-power the machine and you’ll recognise the symptoms immediately: the blade bogs down mid-cut, the engine screams, cut speed drops, and the blade wears faster because it’s spending too long in the material generating heat.
Broadly, for walk-behind cutters:
- Lower-power machines suit patch work, repair jobs, shallow joint cutting and smaller floor areas – work that’s intermittent rather than continuous
- Higher-power machines are for contractors cutting deep, cutting long runs, or cutting daily as their core business
The industry rule of thumb is that once you’re regularly cutting beyond about 100 mm deep, several days a week, you should be looking at a serious step up in power rather than trying to make a light machine work harder.
Petrol, diesel or electric? For most Indian site conditions, petrol is the practical answer:
- Petrol – portable, no dependence on a power connection, strong torque, and easy to service almost anywhere. This is why both our models run air-cooled petrol engines. Air cooling also means no radiator to maintain and better heat dissipation during long continuous cuts.
- Electric – quiet and emission-free, so it’s useful for indoor and confined work, but you’re tied to a cable or a generator
- Diesel – excellent torque at the top end of the size range, but that’s territory for very large pavement saws
The four things buyers forget to ask about
- Water tank and wet cutting. Cutting concrete dry throws out respirable silica dust, which is a genuine health hazard, and it cooks the blade. A continuous water feed cools the blade, suppresses the dust and extends blade life significantly. Look at the tank capacity – a 40 L tank means fewer interruptions to refill, which matters more than it sounds when you’re mid-way through a long run.
- Push or self-propelled. A manual-push machine is fine for shorter cuts and smaller areas. For long road runs, a semi self-propelled machine keeps the feed rate steady, which produces a straighter, cleaner cut and a much less exhausted operator by 4 pm.
- Frame rigidity and weight. Vibration is the enemy of a straight cut. A reinforced steel chassis holds the blade in alignment under load; a light, flexy frame lets the blade drift and chip the edges. Yes, a heavier machine is harder to load into a tempo – but that stability is exactly what you’re paying for.
- Spares, service and who picks up the phone. This is the one that hurts six months later. A cutter that’s down for three weeks waiting on a shaft bearing has cost you more than the price difference between a cheap machine and a good one. Check that the manufacturer stocks genuine spare parts and has a support presence near your sites before you commit.
Where MKG's cutters fit
Our concrete cutting machines come in two models, and they’re deliberately positioned at two different ends of the work:
CNO-12 | CNO-20 | |
Blade size | 350 mm (12″/14″) | 500 mm (16″/20″) |
Max cutting depth | 90–135 mm | 170–270 mm |
Engine | Air-cooled petrol, 5.6 kW | Air-cooled petrol, 8.7 kW (11.7 HP) |
Driving | Manual push | Semi self-propelled |
Water tank | 40 L | 40 L |
Weight | 83 kg | 117 kg |
- Choose the CNO-12 if your work is floor joints, industrial flooring, utility channels, repair patches and general contracting where cuts stay under about 130 mm. It’s lighter to move between sites and easier to handle in tighter spaces.
- Choose the CNO-20 if you’re in roadwork, pavement maintenance, expansion joints on highways or full-depth panel cutting. The larger blade and the extra engine capacity are what let it hold a steady feed rate through thick, reinforced sections instead of labouring.
Both run handle-rotation depth adjustment for fine control, both carry the same 40 L water tank for continuous blade cooling and dust suppression, and both sit on a reinforced steel frame built to keep the blade true under load. Full technical details are in the product brochure, and you’ll find our wider light construction machinery range – plate compactors, walk-behind rollers and power trowels alongside it, since most cutting jobs sit next to a compaction or finishing job anyway.
Your five-minute buying checklist
Before you sign anything, run through this:
- Material – what am I cutting most often, and is it abrasive (asphalt, green concrete) or hard (cured, reinforced)?
- Depth – what’s my typical cut depth, and does the machine handle it at around 70% of its rated capacity rather than 100%?
- Blade – does the diameter give me that depth after allowing for the arbor and flanges, and is the bond matched to my material?
- Power – does the engine comfortably drive that blade at that depth, all day, without bogging?
- Duty cycle – occasional use or daily production work? This decides how much machine you should be buying.
- Support – spares availability, service response, and warranty terms in writing.
And one more, which is really a question about your business rather than the machine: if you only need a cutter for a single project, buying may not be the right call at all. We’ve written a full breakdown on renting vs purchasing construction equipment that walks through the utilisation maths and our rental business exists precisely for the jobs where ownership doesn’t make sense yet. If it does make sense later, our buy-back and recon machine options make that transition straightforward.
Conclusion
Blade size sets your depth ceiling and it’s about a third of the diameter, not half. Cutting depth should be chosen from the job you do every day, not the deepest cut you’ll ever face. Engine power is what turns that blade-and-depth combination into an actual working machine rather than a struggling one. And the blade bond, the water supply and the service backup quietly decide whether the machine you bought stays profitable.
Get those right and a concrete cutter becomes one of the most dependable, hardest-working machines on your site.
Not sure which model fits your work? Tell us what you’re cutting, how thick it is and how often and we’ll tell you straight which machine you actually need.
Email: info@mkgworld.in | Call: +91 95222 39320
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