In partnership with Hilti
Hilti has earned our recommendation for its angle grinders for years. The engineering team knows what Pros demand, and they’ve consistently pushed the bar higher. This is most evident in the Nuron lineup, where Hilti’s cordless angle grinders have impressed us with both their performance and technology upgrades.
Turning our attention to the compact angle grinder class, the Hilti Nuron AG 4D-22 may be the entry point of the line, but it’s far from entry-level. I had the opportunity to talk with part of the team responsible for bringing this model to life, and I’ll share what I learned about the performance and safety that sets it apart from other cordless angle grinders.
Performance Upgrades
When the wheel hits metal, the first thing you’ll notice about the AG 4D-22 is how much more confident it is than the previous version. That’s because the Nuron brushless motor now has power equivalent to a 9-amp corded model: a 30% increase. With a top speed of 7700 RPM and the stronger motor’s higher torque, you’ll enjoy faster cutting, more efficient grinding and surface prep, and improved overall productivity.
There’s also an auto-restart feature on the paddle switch version that’s different from what we’ve seen on other cordless angle grinders. If the wheel binds up from too much pressure, keep pressing the switch, back off within two seconds, and the motor will automatically restart. It may seem like a small thing, but getting back to cutting or grinding without having to pull the wheel all the way out and cycle the trigger really does improve your workflow.
3D Active Torque Control (ATC)
A feature unique to Hilti and rolling out into its entire cordless angle grinder lineup is 3D Active Torque Control (ATC). It’s a function that stops the motor if it detects a sudden movement in any direction.
It’s tempting to think of it like other kickback control mechanisms that stop the motor when they sense a quick rotation from a wheel bind-up. 3D ATC does that, but much more.
Imagine there’s a bubble surrounding the grinder, and if the grinder leaves that bubble too quickly, 3D ATC kicks in. Not only will it stop the motor in a kickback event, but it will also stop if someone accidentally hits your arm, bumps into you, you quickly react to something that comes into your field of work, or anything else that causes a sudden movement of the grinder. With the development of this technology, the safety function goes far beyond kickback alone.
Dialing in the Design
One of the biggest changes the engineering team made to the physical shape of this grinder involves the handle. It’s now significantly smaller to better accommodate a wider range of hand sizes and to be more comfortable for extended use applications.
You might have noticed the metal foot protruding down near the battery connection. It serves as a spark deflector, directing sparks away from the battery. It also doubles as a tether point, so you don’t have to loop your tether around the handle when you’re working at height.
Additional Features
- Electronic Brake: Stops the wheel in less than two seconds for increased safety
- Mesh Intake Cover: Extends service life by preventing metal debris from entering the housing
A Must-Have Accessory
While you’ll need to select the guard, shroud, and other accessories you need for the types of jobs you’ll be doing, there’s one other accessory we highly recommend everyone add: the Kwik Lock flange nut.
This innovative replacement for the stock flange nut makes wheel changes tool-free. Just hand-tighten it when you install a new wheel, and it remains easy enough to loosen by hand when you’re done without compromising the holding strength against the wheel. It’s easy to use, saves time, and you won’t have to wonder where you left your spanner wrench.
Additional Hilti Angle Grinder Options
There are four angle grinders available in this category to match the way you work. No matter which version you choose, you get the same motor and safety package. The main differences are that the slide switch models have a 6-mode variable speed, and the paddle switch models feature the automatic restart function I noted earlier.
- AG 4S-22-4.5: Slide switch model with 4.5-in guard
- AG 4S-22-5: Slide switch model with 5-in guard
- AG 4D-22-4.5: Paddle switch model with 4.5-in guard
- AG 4D-22-5: Paddle switch model with 5-inch guard
When to Use the Hilti AG 4D-22 Angle Grinder
When it comes to applications, the AG 4D-22 is appropriate for nearly any small angle grinder jobs, including concrete surface prep. Here are a few examples:
- Cutting and grinding stainless steel and other metals
- Deburring and polishing metal
- Cutting and grinding concrete, masonry, stone, and roof tiles
- Cutting tiles (continuous-rim diamond discs required)
It used to be that cordless angle grinders were a convenient supplement to corded models for short-duration work, but weren’t really the best choice as your primary grinder. That’s not the case anymore.
Part of it is the performance and runtime that Hilti’s Nuron batteries and brushless motors offer. Now, Hilti also has advanced charging solutions that can keep you going with fewer batteries to manage.
The newest is the C 8D/DC-22 Dual-Bay Flash Charger. It actively cools your Nuron battery packs and is capable of the fastest charging rates. While large-capacity batteries see the greatest improvements in charging times, it’s also highly effective on the smaller ones, like the B 22-85 and B 22-195, which are recommended for use with the AG 4D-22 angle grinder.
Ready to buy? Head over to Hilti’s website to learn more or talk to your local Hilti sales rep to see how the latest generation of cordless angle grinders can change the way you work!
