DeWalt 20V MAX Brushless Cordless 4 1/2 in. Paddle-Switch Grinder (Tool Only)

A cordless grinder earns its keep the first time you don’t have to drag an extension cord through dust and rebar. That’s exactly where the DeWalt 20V DCG408 grinder has been living for me: fast, untethered cuts and cleanup grinds on jobs where mobility and control matter more than brute force.

Setup and first impressions

Out of the box, you get the grinder, inner/outer flanges, a hex wrench, a side handle, a standard grinding guard, and a clip‑on guard for cutting. There’s no battery or charger, so plan on using your existing 20V MAX packs. I started with a 5.0Ah battery for general work, then swapped to a compact pack when I needed to get into tighter spaces.

The grinder is compact at about 13 inches long and a hair under 5 pounds bare. With a 5.0Ah battery, the balance sits slightly tail‑heavy, which I actually prefer for cuts—it lets me guide the head precisely while the rear hand manages weight. The guard adjusts tool‑free and locks positively, and the side handle threads on either side for left‑ or right‑handed work.

Power and speed under load

This is a brushless, 4.5‑inch, 9,000 RPM grinder rated at up to 850 MWO. In practice, it’s punchy for a 20V 4.5‑inch class tool. I ran it through three common tasks:

• Cutting 1/2‑inch rebar with a Type 1 cutting wheel: It stepped cleanly through without bogging, and the motor held speed as long as the feed pressure stayed reasonable. With a fresh 5.0Ah pack, I was solidly in the “do a small bundle of cuts and move on” territory—just what I expect from a compact cordless grinder.
• Trimming brick veneer for an electrical box: With a diamond wheel and the included clip‑on cutting guard, the grinder maintained speed through shallow scoring passes and full‑depth cuts. The brushless motor’s torque curve helps keep the wheel from stalling when you square up on the cut.
• Cleaning up welds on 1/8‑inch plate: Using a flap disc and then a grinding wheel, it stayed smooth at mid‑pressure. Push too hard and the overload protection politely intervenes before you get into “angry grinder” territory.

No cordless 4.5‑inch grinder matches a high‑amp corded model or a 60V big brother on deep grinding or long surfacing jobs. But for targeted cuts, prep, and punch‑list metalwork, the DCG408’s power is credible and consistent.

Safety and control features

DeWalt’s Perform & Protect features show up here in a useful way. The E‑Clutch detects binding and limits reaction torque, and the Kickback Brake stops the wheel very quickly when a bind occurs. I forced a couple of test binds in scrap to see how it behaved—each time I got an immediate brake and a controlled stop rather than a violent twist. That’s the difference between a jump scare and a non‑event.

The paddle switch has a safety lock‑off and encourages a grip that’s inherently safer for cutting and grinding. It’s easy to feather and just as easy to drop power the moment you let go. If you like fingertip control, you’ll appreciate the paddle layout.

Ergonomics and vibration

Vibration is well‑managed for this class. With a flap disc or cutting wheel, the grinder feels composed; with a hard grinding wheel, it’s on par with other pro‑grade 4.5‑inch tools. The head shape is low enough to work near surfaces, and the tool length helps with leverage on long cuts. The side handle has enough texture to stay put with gloves on, and the paddle switch is friendly to gloved operation.

Noise is what you’d expect from a 9,000 RPM grinder—hearing protection is mandatory. The mesh intake screens do their job helping keep spark dust and masonry fines out of the motor cavities; after a particularly dusty brick cut, I brushed the screens off and found no obvious grit accumulation inside the housing.

Runtime and batteries

DeWalt’s runtime claim (dozens of cuts in 1/2‑inch rebar on a 5.0Ah pack) tracks with what I see on site. Battery choice matters:

• 5.0Ah 20V MAX: Best all‑around balance of runtime and weight for metal cutting and grinding.
• Compact packs: Good for overhead or tight‑space work but noticeably shorter runtime and a little less punch.
• High‑capacity/PowerStack: If you’ll be cutting masonry or doing extended grinding, a higher‑capacity pack keeps the tool in its power band longer and reduces voltage sag.

Plan on hot‑swapping batteries if you’re doing continuous grinding or lots of deep masonry cuts. The overload protection and thermal management are tuned conservatively; the tool will shut down before cooking itself, which I appreciate.

Guards, wheels, and ease of use

The tool‑free guard adjustment is straightforward and locks firmly without drifting. The included clip‑on cutting guard is worth using; it controls sparks better during cutoff work and gives proper coverage for Type 1 wheels. Wheel changes use the standard two‑flange setup with the provided hex wrench. A true quick‑change wheel system would be faster, but the standard hardware is robust and familiar.

The grinder accepts common 4.5‑inch wheels, and the spindle works with typical accessories. I ran bonded abrasive, flap, and diamond wheels without issue. The inner flange tolerances felt snug and true, limiting wheel wobble.

Durability and maintenance

Between the brushless motor, mesh screens, and conservative electronics, the DCG408 feels built for daily use. After several dusty cuts and metal cleanup sessions, the grinder hasn’t shown heat‑soak problems or inconsistent braking. I make a habit of brushing the intake screens at the end of the day and blowing the guard area clean—simple habits that keep grinders alive.

DeWalt backs it with a 3‑year limited warranty, one year of free service, and a 90‑day satisfaction guarantee. That’s a solid safety net for a tool that will inevitably live hard.

What I’d improve

• More sustained grinding power: For heavy beveling or surface prep, you’ll still wish for a corded 11–13A grinder or DeWalt’s higher‑voltage models.
• Wheel change speed: A keyless nut option would be a welcome addition for frequent accessory swaps.
• Battery appetite: Like all cordless grinders, it drains packs quickly under heavy load. Budget for extra batteries if this is your primary grinder.

Who it’s for

• Electricians, remodelers, and HVAC techs who need quick, controlled cuts in metal or masonry without a cord.
• Fabricators and mechanics for spot grinding, weld cleanup, and on‑vehicle work where a cord is a hassle.
• Pros already on DeWalt 20V MAX who want a dependable 4.5‑inch grinder that prioritizes safety and control.

If your day is wall‑to‑wall grinding or you routinely need 5‑ or 6‑inch wheel capacity, look higher up the power ladder. Otherwise, this hits the sweet spot for portability and real‑world jobsite usefulness.

Recommendation

I recommend the DCG408 for anyone invested in DeWalt’s 20V MAX line who needs a compact, safe, and capable 4.5‑inch grinder. It maintains speed under load better than many in its class, the paddle switch and anti‑kickback features inspire confidence, and the guard system is quick to adjust for switching between grinding and cutting. You give up some sustained grinding power and you’ll feed it batteries on heavier jobs, but that’s expected for a 20V 4.5‑inch platform. As a go‑to cordless grinder for cuts, prep, and punch‑list tasks, it’s a reliable, well‑sorted choice.