At the tail end of 2025, DeWalt released two new Atomic 20V Max angle grinders to the market—the 4-inch DCG400 and the 4 1/2-inch DCG402. These models filled a specific gap in the 20V Max lineup, but they also raised a few questions for us. Today, I’ve got my hands on the DeWalt DCG402 20V Max Atomic Grinder to see what it has to offer and find out what sets these tools apart from other grinders on the market.
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DeWalt Atomic 20V Max Angle Grinder Performance
- No-Load Speed: 11,000 RPM
- Max Power Output: 760 MWO
- Max Disc Diameter: 4 1/2 in.
- Motor Type: Brushless
- Spindle Size: 5/8-11
The DeWalt DCG402 is powered by a brushless motor that churns out up to 760 MWO with a top speed of 11,000 RPMs. Plus, DeWalt added an extra layer of safety in the form of an Anti-Rotation System. This automatically halts the disc in the event of a bind-up and reduces reactionary torque.
The speed is noticeably faster than what we’re used to seeing from this class, but it doesn’t tell the whole story.
The DeWalt angle grinder we reach for most often is the 60V Max DCG418. Sporting a 6-inch wheel, its top speed is lower at 9,000 RPM, but its power level is much higher at 2,300 MWO. In a side-by-side comparison, I was able to stall the Atomic model much more easily than the more robust 60V model.
Of course, comparing those two head-to-head isn’t really fair, considering they’re in completely different classes and run at different voltages. With the Atomic running roughly 1/3 the power of that much larger model, it’s exactly the kind of result we’d expect.
Pro Tip: As angle grinder wheel capacity goes up, RPMs typically drop because they don’t need to spin as fast to keep the edge speeds high. A 4 1/2-inch wheel spinning at 11,000 RPM has an edge speed of 25,905 FPM, while a 6-inch wheel at 9,000 RPM runs 28,260 FPM at the edge.
A better comparison is against the DCG408—another 4 1/2-inch paddle switch small angle grinder. Boasting a similar feature set, it tops out at 9,000 RPM with 850 MWO of power. As part of the Atomic line, the DCG402 is a little bit of a step down in power but also even more compact, hinting that it’s built for a different purpose.
In fact, the release of the 4-inch DCG400 alongside this model helps complete the picture. As we look more closely at the designs of the Atomic grinders, we can see what sets them apart.
DeWalt Atomic 20V Max Angle Grinder Comparison: DCG400 VS DCG402
With this product release, DeWalt introduced two nearly identical models at the same time. It’s not just a paddle switch vs a slide switch, though. This got me thinking: why two new grinders so closely related, and what are the key differences? With those questions in mind, we reached out to DeWalt to get some clarification.
The DCG400 is a 4-inch model rather than a 4 1/2-inch like the DCG402. This smaller size is very common in industries like pipe fabrication and automotive fabrication, typically used alongside full-sized corded angle grinders.
Furthermore, the DCG400 has a higher top speed of 12,500 RPM, which allows it to excel in light to medium-duty applications like cutting, weld finishing, and deburring. It also has a 3/8-24 spindle, which aligns with some of the most common pneumatic small angle grinders accessories on the market.
Lastly, due to its size, the DCG400 isn’t required to accept a side handle, allowing the small gearcase to fit in tighter spaces.
So, if you’re used to a small angle grinder that doesn’t have a side handle, the DCG400 is your direct cordless conversion. On the other hand, the DCG402 replaces slightly larger small angle grinders while maintaining an extremely compact size for its class.
| DCG400 | DCG402 | |
|---|---|---|
| Top Speed | 12,500 RPM | 11,000 RPM |
| Power Output | 755 MWO | 760 MWO |
| Disc Size | 4 in. | 4 1/2 in. |
| Spindle Size | 3/8-24 in. | 5/8-11 in. |
| Price | $299 (bare tool), $599 (kit) | $229 (bare tool) |
DeWalt Atomic 20V Max Angle Grinder Design Notes
- Model: DeWalt DCG402
- Power Source: DeWalt 20V battery
- Weight: 3.9 lbs (bare tool), 5.5 lbs (with 5.0Ah PowerPack battery)
- Tool Length: 10.25 in.
Size and Weight
Right off the bat, my first comment about this grinder was about the size…it’s small! It weighs in at just 3.9 pounds as a bare tool and only jumps to 5.5 pounds with a 5.0Ah PowerPack battery. On top of that, the entire tool is only 10.25 inches long. This is nearly a full 2 inches shorter than the DeWalt 20V DCG415.
These sizing characteristics are right in line with what we expect from DeWalt’s Atomic lineup. The compact design allows for greater access in tight spaces, and it’s also much easier to maneuver than a full-sized model.
Grip and Trigger
Looking down at the grip, it’s clear that DeWalt put in some real thought into their design. First, they opted for a paddle trigger rather than a slide switch, which personally, I prefer because I believe it adds an extra layer of safety. This is almost a direct carry over from pneumatic designs, which I think is a smart move on their part. As the old saying goes, “if it ain’t broke, don’t fix it”.
The grip is draped in a generous amount of rubber overmolding and is only 1.8 inches wide, allowing it fit very comfortably in my medium size hands.
Wheel Changes
Swapping out discs is a pretty standard process on most grinders and typically requires a spanner wrench, but DeWalt wanted to make life a little easier.
Taking a page right out of Metabo’s book, DeWalt uses a large tool-free quick change nut to secure your discs to the spindle. The edge of the nut is knurled, making it easy to get a good grip, even while wearing work gloves.
While this system doesn’t require any tools, there are hex shaped slots on the nut so you can use the included hex wrench or a spanner wrench in the event the nut gets too tight.
Guard and Adjustments
Overall, this grinder feels very solid, and one area in particular is the adjustable disc guard. DeWalt opted for an all-metal two-piece design rather than incorporating any plastics or polymers. This essentially combines the Type A and Type B guards into one.
DeWalt’s design is pretty unique. Most manufacturers simply give you a plastic cutting guard that just slips over the grinding guard, and while it works, they don’t always feel very sturdy. However, the DCG402’s Type A guard locks in securely, ensuring it won’t come loose as you’re working.
Like most modern cordless grinders, the guard is adjustable so you can direct sparks and slag away from your hands or other sensitive surfaces.
Additional Features
- Two-position side handle
- Tool Connect ready
- Compatible with all DeWalt 20V batteries
DeWalt Atomic 20V Max Angle Grinder Price
The DeWalt DCG402 retails for $229 as a bare tool and comes with a 3-year limited warranty, 1 year of free service, and a 90-day money back guarantee.
At the time of writing, there are no kit options available, so be sure to pick up a battery and charger if you’re not already established on their 20V Max platform.
The Bottom Line
After getting some hands-on time with the DCG402, I really do feel compelled to tip my hat the design team. This is a purpose-built tool for tight access that’s well-designed, easy to use, and powerful enough for most light to medium-duty applications. Not to mention, the lighter weight is that much less fatiguing when you don’t need more power.
I think it’s important to also remember that this tool is not going to replace your full-sized angle grinder for those heavy-duty tasks. Rather, the DCG402 shines as a supplemental tool, or even as a replacement for your old pneumatic grinder if you’re looking to ditch to hose and compressor.
Admittedly, it is a little pricey, and the lack of a kit option is a slight bummer if you’re looking to save some money as you cycle in new batteries. But if cordless freedom in a compact and lightweight design is high on your priority list, then DeWalt’s 20V Max Atomic angle grinder fits the bill.
