DeWalt 9 in. 4.9 HP Angle Grinder with No-Lock On

Why I reached for a 9-inch grinder

There are jobs where a 4-1/2-inch or 5-inch grinder simply runs out of steam—beveling thick plate, chasing cuts in concrete, trimming castings, or knocking back large welds where heat and torque matter more than top-end speed. That’s where this DeWalt 9-inch grinder earns its keep. After several weeks cutting pavers, slicing angle iron, and surfacing big welds, I have a good sense of where it shines and what you should know before you bring one to a job.

Build and ergonomics

This is a heavy, full-frame tool and feels like it. At roughly 12.8 pounds, it’s not a one-handed, finesse grinder. The balance is surprisingly neutral for its class, though, with the motor and gearcase laid out so the tool sits predictably in the cut. The trigger handle has a soft, anti-vibe overmold that’s easy to grip with gloves, and the three-position side handle gives you the leverage you need when a 9-inch disc starts biting.

The low-profile gearcase helps when you’re skimming along flat stock or getting into the toe of a fillet weld near an obstruction. Guard adjustments are genuinely quick—no tools required—so rotating the guard as you move around a part doesn’t break your rhythm.

One ergonomic note: this is the no-lock-on version. You must keep the trigger engaged to run the tool. That’s the right call for safety in many shops, but expect some hand fatigue on long, continuous cuts. The vibration control on both the main and side handles does take the sting out of extended grinding sessions.

Power and speed in the cut

On paper, the combination of a 15-amp motor, about 4.9 HP, and a 6,500 RPM no-load speed is exactly what you want in a 9-inch class grinder: slower RPM than a small grinder but more rim speed thanks to the larger disc, and plenty of torque. In practice, it translates to confident, steady removal rates without needing to lean on the tool.

I used it to bevel the edge of 1/2-inch mild steel plate with a 36-grit depressed-center wheel. The grinder held speed under load better than many 7-inch units I’ve used; it didn’t bog unless I got impatient and tried to dig in beyond what the wheel could handle. On concrete pavers with a segmented diamond blade, the tool stayed composed. The soft-start ramps the disc up without that violent twist you sometimes get from big grinders, which makes for cleaner starts and better control when you’re dropping into a cut line.

If you’re coming from smaller grinders, the slower nominal RPM might look like a disadvantage. In reality, with the larger disc diameter, you’re still at an effective cutting speed. What you gain is torque and stability—exactly what you want for heavy grinding and deep cutting.

Safety and control features that matter

The standout here is the anti-rotation E-CLUTCH. I hit a bind while notching heavy angle stock; the disc pinched, and the tool shut down before it had a chance to whip. That’s the difference between a bad scare and a bruised wrist. Add in electronic overload protection and a power-loss reset—so it won’t restart if the power blinks while the trigger is engaged—and you have a conservative safety profile without getting in the way of work.

Soft-start is another subtle win. Big grinders can be jumpy at startup; this one spins up smoothly and predictably. The guard mechanism is sturdy and locks positively, and the 5/8-11 spindle means standard accessories fit without fuss.

Dust handling and durability

Grinding and cutting are messy, and while this isn’t a shrouded dust-extraction grinder, the internal Dust Ejection System helps the motor live in dusty environments. You can feel and see the tool purging fine debris away from the windings. Over time, that matters for brush and commutator life.

Speaking of brushes, serviceability is straightforward. The brush door makes inspections and replacements quick, and the tool has an automatic shutoff when brushes are due. That helps prevent commutator damage, which is how many grinders end up in the scrap bin.

I ran the tool extensively on masonry, and while you’ll still need a proper shroud and a vac to control airborne dust at the work surface, the motor stayed clean enough that I didn’t see the telltale performance falloff or arcing you get from dust-caked brushes.

Setup, accessories, and the small stuff

Out of the box, mounting wheels and adjusting the guard is simple. The spindle is standard, so flap discs, depressed-center grinding wheels, and diamond blades all went on without drama. Do double-check your wheel ratings—9-inch wheels are typically rated around 6,600 RPM, and this grinder’s 6,500 RPM keeps you within spec.

A practical note: verify you have the correct inner and outer flanges for the wheels you plan to run, especially if you switch between cut-off and grinding discs. Keep a spare set in the gang box; it’s cheap insurance against downtime. There’s no case with this tool, and given the size and weight, a dedicated bag or box makes transport and storage far easier.

In the field: metal and masonry

Metalwork is where I felt the biggest productivity jump over smaller grinders. Beveling plate before welding, knocking down multi-pass weld crowns, and cleaning mill scale off wide stock all go faster because you can lean on the torque. The anti-vibration handles make long sessions tolerable, and the tool doesn’t get hot quickly, even under load. I tripped the overload protection only once when I tried to power through an aggressive wire cup that was too heavy-handed for the task; easing off brought it right back.

On masonry, the grinder handled dry cutting of pavers and block cleanly with a segmented diamond blade and a shroud/vac setup. Soft-start makes plunges into concrete less jumpy, and the E-CLUTCH adds a layer of confidence when a kerf closes unexpectedly.

What could be better

• Weight and fatigue: At nearly 13 pounds with a big wheel and no lock-on trigger, continuous cuts can be tiring. The safety benefit is real, but your hands and forearms will feel it.
• No included case: A tool this size deserves a purpose-built case or bag.
• Size constraints: The low-profile gearcase helps, but it’s still a 9-inch grinder. If you’re regularly in tight quarters, this won’t replace a compact grinder.
• Single speed: Fixed speed at 6,500 RPM is appropriate for 9-inch work, but if you rely on wire cups, polishers, or specialty accessories that prefer lower RPM, you’ll want a variable-speed tool for those tasks.

None of these are deal-breakers for heavy grinding and cutting, but they’re worth factoring into your kit.

Reliability, warranty, and value

With heavy use across metal and masonry, I didn’t see signs of premature brush wear or bearing noise. The dust management and brush cut-off give me confidence this tool will hold up under real jobsite conditions. The warranty package—three-year limited, one-year free service, and a 90-day satisfaction window—aligns with expectations in this class. Country of origin is China, which is typical for many pro-grade grinders today.

Value depends on your workload. If you only occasionally need a big grinder, a 7-inch model might be lighter and cheaper while still covering most tasks. If you routinely grind heavy steel or cut masonry, the additional torque and disc capacity here pay off in productivity and control.

Who should buy it

• Fabricators and welders who prep and finish large sections routinely
• Masons and remodelers cutting block, pavers, or chasing joints with a shroud and vac
• Jobsite crews needing a powerful, safer big grinder with modern electronic protections

If most of your grinder work is small-diameter, one-handed tasks, a 4-1/2-inch or 5-inch grinder will feel faster and less fatiguing. Keep those for finesse work and bring this out when material removal and depth of cut matter.

Recommendation

I recommend this DeWalt 9-inch grinder for anyone who needs serious grinding and cutting power with a sensible safety feature set. It combines real torque, a controllable soft start, and an excellent E-CLUTCH that actually intervenes when you need it. The ergonomics and vibration control make long sessions manageable, and the serviceability—brush access, dust management, and overload protection—suggests a long, useful life.

It’s not the right tool for every cut: the weight, size, and no-lock-on trigger demand two-handed commitment and will tire you out on long continuous passes. There’s no case in the box, and you should make sure you have the correct flanges for the consumables you run. But as a dependable, powerful grinder for heavy work, it earns a spot on the cart and pays for itself in speed, control, and safety.