DeWalt 20V MAX XR Brushless Cordless 4-1/2 in. - 5 in. Variable Speed Slide Switch Grinder

Why this grinder earned a spot in my kit

I reach for a cordless grinder more than I thought I would—quick cuts, knocking down welds, cleaning up edges, chasing a line in concrete. This DeWalt grinder hits a sweet spot for those jobs: true 5-inch capability, a brushless motor rated to 1,640 MWO, and variable speed up to a no-load 9,000 RPM. It’s tool-only and part of the 20V MAX line, so it’ll slide into an existing DeWalt setup nicely.

What sets it apart in use is the variable speed. Being able to slow a grinder down and still have solid torque changes how confidently I work on heat-sensitive metals, with flap discs on paint, and with wire wheels. It’s also paired with a safety system that senses a bind-up and shuts the tool down. In the real world, that combo—control plus kickback protection—makes a difference.

Build, handling, and ergonomics

Bare weight is 4.9 pounds, and the overall footprint (about 13.2 inches long) feels compact for a 5-inch grinder. With a 5Ah battery, balance is right where I want it—centered, not nose-heavy, and easy to index for both horizontal grinding and vertical cuts. The side handle gives me a confident two-handed grip and keeps vibration reasonable during longer passes.

The slide switch is side-mounted and positively detented. Mine is on the stiffer side; with gloves on, it’s fine, but bare-handed it takes a firm thumb. The upside is it’s hard to bump on accidentally. The downside is frequent on-off cycles can feel clunky, especially if you’re used to paddle-switch “deadman” grinders. If you strongly prefer a paddle switch for safety or comfort, this isn’t that style.

Fit and finish are typical DeWalt XR: durable overmolds where you need them, clean transitions, and a housing that doesn’t trap too much abrasive dust. After a few weeks on metal and masonry, the vents needed a quick brush-out but showed no clogging.

Power and performance

On mild steel, the grinder pulls like a corded 10–11-amp class tool for short bursts. With a 5-inch cutting wheel, it handled angle iron and rebar without bogging, and it kept up with aggressive grinding on welds using a 36-grit flap disc. The brushless motor comes up to speed smoothly, and throttle response through the speed dial feels linear.

• Thin cutoff wheels: steady power and clean tracking through 1/8-inch steel; the motor keeps the wheel moving without over-speeding at higher settings.
• Flap discs: at mid-range speeds, I could take material down without glazing the disc or discoloring the workpiece.
• Wire wheels: the lower ranges are where variable speed shines—less wire throw and less surface gouging.
• Masonry: paired with a 5-inch diamond blade and a shroud, the top speed is appropriate for scoring mortar and pavers. With variable speed, I could minimize chipping on delicate edges.

Under repeated heavy grinding, it warms up as any compact cordless grinder will. I didn’t hit thermal shutdown in my typical task mix, but if you plan to lean hard into steel for long stretches, you’ll still want a corded 13-amp or bigger grinder. This one is built for mobility and control over marathon hogging.

Variable speed: where it matters

Variable speed isn’t a gimmick on a grinder; it’s a safety and finish tool.

• Heat control: On stainless and thin sheet, slowing the wheel helps avoid blueing and warping. I kept finishes cleaner and spent less time re-work sanding.
• Abrasive life: Running wire wheels and flap discs a notch down often extends their usable life and reduces “burning” the work.
• Noise and comfort: Lower speeds are less shrill and kick up fewer sparks and fines, which makes indoor or occupied-space work less miserable.

The dial is easy to adjust with the off-hand, and the motor’s torque curve feels consistent across the range. I didn’t notice a jumpy transition between steps—just steady, usable increments.

Safety and control

DeWalt’s anti-rotation feature—a sensor-based system that detects a bind and cuts power—worked as advertised. I purposely bound a cutoff wheel in a kerf and the tool snapped off quickly, preventing the wrist-twist you can get with non-electronic grinders. It’s not a free pass to get sloppy, but it adds a margin of safety I appreciate, especially in awkward cuts.

The slide switch allows for latching on, which is nice for long grinding passes, but it’s not everyone’s cup of tea for safety. With gloves and good habits, I felt in control; I’d still prefer a paddle for overhead or cramped work.

Dust management and connectivity

For masonry work, I connected the grinder to a compatible DeWalt dust extractor that supports wireless tool control. Paired together, the vac kicked on when I started grinding and coasted down after I stopped. The workflow improvement is real—one less thing to fumble when you’re scoring a line or cleaning out a joint. If you do a lot of tuckpointing or tile prep, this pairing is worth considering.

The tool is also “chip ready” for Tool Connect, which is useful if you manage a fleet or want asset tracking and inventory support. For solo users, it’s nice but not essential.

Batteries and runtime

This tool ships without a battery or charger. On 20V MAX packs:

• 5Ah: Best balance. Good runtime for typical metalwork sessions and most cut-and-go tasks.
• 8Ah/10Ah: noticeable runtime boost, but it makes the tool feel a bit top-heavy in some positions.
• Compact 2Ah: workable for quick cuts, but drains quickly and sags sooner under heavy load.

Runtime is inevitably tied to how aggressive you are and the abrasive type. Variable speed helps—running a notch or two down on lighter tasks meaningfully extends battery life without compromising results.

What I like

• Useful variable speed across a wide range, with enough torque to keep the job moving.
• Strong brushless performance in a compact, well-balanced 5-inch format.
• Anti-rotation shutoff adds meaningful safety against bind-ups.
• Ecosystem perks: wireless vacuum control and Tool Connect readiness.
• Solid ergonomics with a comfortable side handle and manageable vibration.

What I’d change

• The slide switch on my unit is stiff. It’s secure, but frequent on/off cycles are tedious, and users who prefer paddle switches won’t convert.
• Tool-only purchase means factoring in batteries/charger if you’re not already on the platform.
• Continuous heavy grinding will still favor a higher-amp corded grinder; this excels at mobile, task-based work rather than all-day demolition.

Who it’s for

• Trades and DIYers already on DeWalt 20V MAX who want a variable-speed grinder with real 5-inch capability.
• Metalworkers and fabricators who value heat control and surface finish on stainless, sheet, and painted surfaces.
• Remodelers and masons pairing it with a dust shroud and extractor for silica control.
• Anyone who appreciates electronic kickback protection and the option to integrate with a fleet management system.

If you rely on a paddle switch for safety policies or personal preference, you may want DeWalt’s paddle-switch variant instead. And if your work involves hours of heavy stock removal, a larger corded grinder will still be more efficient.

Final recommendation

I recommend this DeWalt grinder for users who value control and safety as much as raw speed. The variable-speed brushless platform delivers versatile, predictable performance across metal, masonry, and prep work, and the anti-rotation shutoff adds a meaningful layer of protection. It’s compact, balanced, and integrates neatly into the 20V MAX ecosystem, with thoughtful touches like wireless dust-extractor control and Tool Connect readiness.

The caveats are clear: it’s a slide-switch tool with a firm action, and it’s optimized for task-based, mobile grinding—not all-day heavy hogging. If that aligns with the way you work, it’s a dependable, capable grinder that earns its space in the bag.