The Milwaukee 3672-20 M18 FUEL 4-1/2"-6" Variable Speed Braking Grinder, Paddle Switch w/ ONE-KEY is a cordless angle grinder built for pros who need real cutting and grinding power without giving up mobility. This is a cordless angle grinder designed for grinding and cutting metal and masonry-related materials with common 4-1/2 inch to 6 inch accessories. Model Number 3672-20. If you already run M18 tools and want a grinder that does more than light touch-up work, this is the kind of bare tool that actually earns space in the truck.

The big story here is output and control. Milwaukee rates this grinder at 13A corded power, and the POWERSTATE brushless motor runs from 3,000 to 9,000 RPM. On the job, that matters because a grinder that can hold speed under load cuts faster, grinds cleaner, and feels less bogged down when you are pushing through hard material. The 4-mode variable speed setup also makes this more versatile than a one-speed grinder. You can slow it down for better control with certain accessories and turn it up when you need faster material removal.

Safety and confidence are a real part of the package, not an afterthought. RAPIDSTOP braking is one of the standout features on this model, stopping most wheels in less than 2 seconds, with published stop times of 0.99 seconds for a cutting wheel, 1.2 seconds for a diamond wheel, and 2.0 seconds for a grinding wheel shown in the product imagery. Add in the electronic clutch for kickback protection and overload protection for motor life, and you get a grinder that is built to stay in control when conditions are less than ideal.

Milwaukee also got the day-to-day design details right. The paddle switch setup gives you a natural grip and quick shutoff feel that many users prefer for angle grinders, especially during awkward cuts and overhead work. The anti-vibration side handle helps when the tool is in your hands for more than a few quick passes, and the straight handle layout keeps the body compact enough to maneuver around stock, steel, and tight fabrication spaces. At 15 inches long and 5.4 pounds bare, it has the size and balance you want in a serious cordless grinder without feeling oversized.

Accessory handling is another plus. This Milwaukee grinder uses a common 5/8 inch-11 spindle, so finding cutoff wheels, grinding wheels, and diamond accessories is straightforward. Product imagery also shows a spindle lock and tool-free accessory change and guard adjustment, which speeds up changeovers when you need to move from one task to the next. In plain terms, less time wrestling with the setup means more time actually cutting and grinding.

For fleet users and anyone managing multiple crews, ONE-KEY adds real value. The tool can be tracked and managed through Milwaukee's ONE-KEY system, which helps with tool visibility, inventory control, and customization. That is not just a tech feature for the sake of it. If your tools move between vans, gang boxes, and jobsites, knowing where they are and keeping better control of your inventory can save money fast.

Battery platform matters with a grinder because these tools demand a lot from the pack. The Milwaukee 3672-20 M18 FUEL 4-1/2"-6" Variable Speed Braking Grinder, Paddle Switch w/ ONE-KEY is compatible with all M18 batteries, and Milwaukee specifically calls out pairing it with the M18 REDLITHIUM FORGE XC8.0 battery pack for high-output performance. This is sold as a bare tool, so batteries and charger are not included. That makes the most sense for users who are already on the M18 system and want to add a high-performance grinder without buying another starter kit.

Who should buy it? Metal fabricators, welders, ironworkers, mechanical trades, remodelers, and general contractors who need one cordless grinder to handle both cutoff and grinding work will get the most out of it. It is also a smart fit for crews that already use ONE-KEY and want better tool tracking. If you only need a grinder for occasional light-duty cleanup, this may be more tool than you need. If you need cordless performance that is meant to replace more corded grinder time, this is exactly the point of the tool.

One Of The Better Cordless Grinders For Guys Who Normally Reach For A Cord

The Milwaukee 3672-20 M18 FUEL 4-1/2"-6" Variable Speed Braking Grinder, Paddle Switch w/ ONE-KEY makes a strong case for leaving the corded grinder in the box more often.

• Who it's for: Pros already on M18 who need a serious cordless grinder for cutting, grinding, and daily metal work.
• Why it stands out: You get 13A-class output, variable speed, fast braking, kickback protection, and ONE-KEY in one platform tool.
• Worth knowing: This is a bare tool, so plan on adding a battery and charger if you are not already running Milwaukee M18 packs.

• Is this a bare tool? Yes. The Milwaukee 3672-20 is sold without a battery or charger.
• What battery platform does it use? It runs on Milwaukee M18 batteries and is compatible with all M18 battery packs.
• What size accessories does it accept? It is designed for 4-1/2 inch to 6 inch accessories and uses a 5/8 inch-11 spindle.
• Does it have variable speed? Yes. It has 4 speed settings with an RPM range of 3,000 to 9,000 RPM.
• Does it support tool tracking? Yes. This grinder is ONE-KEY enabled for tool tracking and management.