DeWalt ATOMIC 20V MAX 4 in. Angle Grinder Kit with XR POWERSTACK

Why a 4-inch cordless grinder earned a spot in my kit

I first pulled out DeWalt’s Atomic 4-inch grinder to flush-cut a cluster of shiner nails inside a finished cabinet where a 4-1/2-inch grinder simply wouldn’t fit with the guard on. That set the tone for my time with it: compact access, high speed, and just enough grunt to get small metal work done quickly without dragging a cord across a delicate space.

For clarity, this is a true 4-inch grinder. If your workflow revolves around 4-1/2-inch or 5-inch wheels, this isn’t the right size. But if you want a small, fast cutter/grinder for tight quarters and detail work, the Atomic format makes a lot of sense.

Setup, ergonomics, and controls

The slim body and paddle switch feel familiar if you’ve used DeWalt’s recent grinders. The paddle’s lock-off is easy to engage with a thumb roll, and there’s no lock-on—good for safety, slightly tiring for long polishing sessions. At 12,500 RPM (no load), it spins up with a noticeable torque twist, so I appreciated the grippy overmold and neutral balance with the included XR POWERSTACK 3.5Ah packs.

Two things stood out immediately:
- Forward exhaust: the motor’s airflow nudges dust and chips away from my face in most orientations. In a few awkward cuts it pushed dust toward the cut line, but overall it’s a plus for visibility and comfort.
- Small head and guard package: with the included Type B guard fitted, I could sneak into places where my 4-1/2-inch grinder is a no-go. Switching to the clip-on Type A guard for cut-off work is quick and secure.

Wheel changes are straightforward: spindle lock, outer flange, and a single wrench. The reversible inner flange accepts 3/8-inch and 5/8-inch non-hubbed accessories, which is unusual flexibility for a 4-inch grinder. If you rely on hubbed wheels or threaded 5/8-11 accessories, this isn’t the platform; plan on non-hubbed wheels only.

Power, speed, and what it cuts well

DeWalt rates the brushless motor at 755 MWO, and the grinder feels snappy at the trigger—especially with the POWERSTACK packs that deliver current without sag. At the wheel, the performance sweet spot is:
- Fast cut-off work with 1/16-inch or 1/8-inch Type 1 wheels
- Light grinding and touch-ups with thin Type 27 wheels and flap discs
- Deburring, rust removal, and minor surface prep on smaller parts

In practical terms, here’s what I did without bogging:
- Flush-cut framing nails and screws cleanly with a 1/16-inch wheel
- Trimmed 1/2-inch EMT and small angle iron for brackets
- Sharpened mower blades with a 60–80 grit flap disc
- Nipped 1/4-inch bolts and cleaned up weld spatter on a small fabrication

Where it shows its size is heavy grinding on thicker steel. It will do it, but if you spend your day leaning into a 1/4-inch wheel on plate, a larger 4-1/2 or 5-inch grinder with more mass and wheel options is a better fit. The Atomic’s high RPM makes it feel fast and efficient when the wheel is thin and the contact patch is small; it’s less at home as a brute-force hogger.

Noise-wise, expect the high-pitched note typical of compact high-RPM grinders. Vibration is well controlled for the class, and I didn’t notice hot spots on the housing during discreet, task-based use. On longer grinding passes I gave it a breather now and then, which I’d do with any small grinder.

Safety and control features that matter

Two electronic safeties stood out:
- Anti-rotation system: if the wheel pinches, stalls, or binds, the tool stops. It tripped a couple of times when I let a cut close on rebar—the restart requires cycling the switch, which is exactly what you want after a bind-up. It’s a real layer of protection without feeling overbearing.
- Electronic brake: when you release the paddle, the wheel stops in roughly a second. In cramped spaces that rapid stop reduces incidental scrapes and speeds up repositioning between cuts.

I view both as meaningful, everyday safety gains. They don’t turn a grinder into a beginner’s tool, but they do add margin when you’re working one-handed on a ladder or in a cabinet.

Batteries, charger, and runtime

The kit’s two 3.5Ah XR POWERSTACK batteries are a smart pairing. Compared to standard cylindrical-cell packs, these feel peppier under sudden load and keep the tool compact. For cut-off work—say, a dozen or two short cuts punctuated by layout and clamp time—one pack lasted a typical session, and the second pack kept me moving without waiting on a charge.

Grinding is always the battery killer on cordless. With a flap disc on mower blades, I got through a set comfortably on one pack, but a more aggressive wheel will drain faster. If you routinely grind rather than cut, a higher-capacity pack will extend run time, but it also makes the tool feel less nimble. The included charger brings the small packs back up quickly enough that the two-battery rotation avoided downtime in my workflow.

Accessory ecosystem and guard system

Accessory flexibility is the Atomic 4-inch grinder’s biggest caveat. The good:
- Works with both 3/8-inch and 5/8-inch non-hubbed 4-inch accessories via the reversible inner flange
- Comes with both a Type B grinding guard and a clip-on Type A cut-off guard
- Spindle lock simplifies wheel changes with a single wrench

The limitation is the 4-inch size itself. In North America, 4-1/2-inch wheels are far more common on the shelf. You can absolutely find quality 4-inch cut-off wheels, grinding wheels, and flap discs—but selection is thinner, and you’ll need to keep an eye on arbor type. If you maintain your own stock or order in bulk, it’s a non-issue. If you rely on a big-box stop mid-job, the 4-inch format may feel limiting.

A quick note on safety ratings: at 12,500 RPM, use only accessories rated for that speed or higher.

Build quality, maintenance, and extras

Fit and finish are solid: clean guard detents, positive paddle action, and a robust spindle lock. The brushless motor should reduce maintenance compared to brushed designs. I also like that it’s Tool Connect chip–ready if you’re tracking assets across crews; I didn’t need it for my shop, but it’s a practical addition for pro fleets.

The claim of being lighter than a comparable pneumatic grinder aligns with the in-hand feel—this is a small package that’s easy to control in awkward positions. Fans will appreciate that it plays nicely with the rest of the 20V MAX ecosystem.

What I liked

• Compact head and true 4-inch form factor gets into places a 4-1/2-inch grinder can’t
• Strong cut-off performance with thin wheels; crisp, fast brake
• Anti-rotation safety is effective without being overly intrusive
• POWERSTACK packs deliver punch in a small footprint; two-battery kit minimizes downtime
• Flexible arbor support for 3/8-inch and 5/8-inch non-hubbed accessories
• Guard swap between grinding and cutting is quick and secure

What could be better

• Limited 4-inch accessory availability compared to 4-1/2-inch; non-hubbed only
• No lock-on; fine for safety, fatiguing for long polishing/grinding sessions
• Not the right tool for heavy, sustained grinding on thick steel
• High-pitch noise at 12,500 RPM is noticeable—hearing protection is a must

Who it’s for

This grinder best suits electricians, remodelers, HVAC techs, fabricators, and DIYers who need a compact, cordless cut-off and light grinding tool that reaches tight spaces and finishes small tasks quickly. If you’re already in the 20V MAX platform and you appreciate the POWERSTACK packs, it slots in smoothly. If your day-to-day requires 4-1/2-inch or 5-inch wheel compatibility, or you depend on hubbed accessories, consider a larger grinder.

Recommendation

I recommend the Atomic 4-inch grinder as a compact, high-speed cut-off and light-duty grinder for tight-space work, particularly for users invested in DeWalt’s 20V MAX platform. It’s easy to control, stops fast, and the anti-rotation safety adds real value. The kit’s two POWERSTACK batteries keep it nimble and productive.

I would not recommend it if you expect one cordless grinder to do it all, especially heavy grinding or 4-1/2-inch/5-inch wheel work. The 4-inch format is the draw here—and also the limitation. If that aligns with your jobs, this is a capable, well-executed tool that earns its keep.