If you already own 20V MAX batteries and want a fast electronic brake with kickback sensing, check the DEWALT 20V MAX XR 4-1/2-inch grinder (DCG405B, tool only); if you already own 18V LXT batteries and want automatic speed adjustment with rotation-stop sensing, check the Makita 18V LXT 4-1/2-inch/5-inch grinder (XAG04Z, tool only). Both are brushless cordless angle grinders sold as bare tools, so the battery platform you own decides much of the value. The DEWALT is a 20V MAX XR brushless 4-1/2-inch tool with a slide switch, a Kickback Brake that engages on pinch, stall or bind-up, an electronic brake the listing says stops the wheel in 2 seconds or less on average, and Power Loss Reset against restarts after a power disruption; the box includes a 4.5-inch Type 27 guard, side handle, hex key and flanges. The Makita is an 18V LXT brushless 4-1/2-inch/5-inch cut-off/angle grinder with Automatic Speed Change that adjusts speed and torque during the cut, Active Feedback-sensing Technology that shuts the motor off if wheel rotation is suddenly forced to stop, and a listed maximum rotational speed of 8,500 rpm; its listing claims the electronically controlled BL motor can deliver up to 50% longer runtime per charge. Neither variant page showed a price in its buy block on 09/13/2026, so no price is stated here — confirm the live figure before deciding.
Choose by your situation
| Situation | Model to consider | Main tradeoff |
|---|---|---|
| You run DEWALT 20V MAX batteries, cut metal where bind-up is likely, and want the wheel stopped fast | DEWALT DCG405B | Tool-only format adds nothing if you are outside the 20V MAX system; 4-1/2-inch capacity only, and the observed offer ships and sells through a marketplace seller rather than Amazon itself. |
| You run Makita 18V LXT batteries, grind and cut mixed materials, and want the tool to adapt speed and cut power on sudden stops | Makita XAG04Z | Tool-only format adds nothing if you are outside the 18V LXT system; runtime gains depend on the battery you pair it with, which is not in the box. |
Cordless grinders, side by side
| Criterion | DEWALT DCG405B | Makita XAG04Z |
|---|---|---|
| Battery platform and motor | 20V MAX XR, brushless with no brush changes | 18V LXT, BL brushless with electronic energy control |
| Disc capacity | 4-1/2-inch | 4-1/2-inch and 5-inch cut-off/angle work |
| Format | Tool only: variant title names the bare tool, and the box list names guard, handle, key and flanges | Tool only: variant title names the bare tool without battery or charger |
| Safety response | Kickback Brake on pinch, stall or bind-up; electronic brake stops the wheel in 2 seconds or less on average; Power Loss Reset | Active Feedback-sensing Technology shuts the motor off if wheel rotation is suddenly forced to stop |
| Cutting behavior | Guard, flanges, side handle and hex key included for setup | Automatic Speed Change adjusts speed and torque during operation; listed maximum 8,500 rpm |
| Observed standing | 4.7 out of 5 stars across 1,894 ratings | 4.8 out of 5 stars across 3,120 ratings |
DEWALT DCG405B: the fast-brake pick for 20V MAX owners
The DEWALT 20V MAX XR Angle Grinder (DCG405B), tool only suits metal work where a disc can pinch: the Kickback Brake reacts to pinch, stall or bind-up, the electronic brake stops the wheel quickly, and Power Loss Reset keeps the tool from restarting on its own after a power disruption. Limits are scope and supply: it covers 4-1/2-inch wheels, it brings no battery or charger, and the Amazon US variant page observed on 09/13/2026 showed its variant-block offer shipped from and sold by Two Kings LLC with quantity selector, Add to cart and Buy Now, while the price block read “To see product details, add this item to your cart,” so confirm the live price and seller before deciding.
Makita XAG04Z: the adaptive pick for 18V LXT owners
The Makita 18V LXT Cut-Off/Angle Grinder (XAG04Z), tool only suits mixed grinding and cutting where load changes mid-cut: Automatic Speed Change adjusts speed and torque as demands shift, AFT cuts the motor if the wheel is suddenly forced to stop, and the page lists up to 50% longer runtime per charge from the electronically controlled BL motor with a maximum of 8,500 rpm. Limits are scope and pairing: it brings no battery or charger, so real runtime follows the pack you attach. The Amazon US variant page observed on 09/13/2026 showed its variant-block offer shipped from and sold by Amazon.com with quantity selector, Add to cart and Buy Now, while the price block read “To see product details, add this item to your cart,” so confirm the live price before deciding.
Where to check the exact variants
Compare the DEWALT DCG405B 20V MAX XR 4-1/2-inch grinder, tool only (variant-block offer shipped from and sold by Two Kings LLC, observed 09/13/2026, price not shown) against the Makita XAG04Z 18V LXT 4-1/2-inch/5-inch grinder, tool only (variant-block offer shipped from and sold by Amazon.com, observed 09/13/2026, price not shown). As an Amazon Associate I earn from qualifying purchases. Own a 20V MAX shelf, take the DEWALT for its brake; own an LXT shelf, take the Makita for its adaptive cut.