A couple of years ago, I bought a Makita 18-volt model XAG01 4 1/2-inch angle grinder as a bare tool to add to my Makita 18V LXT cordless platform. The tool has been on the market since 2006, and I thought it might be an ideal companion to my corded model, which is a Metabo W8-115.

Given its limited power and runtime, I’ve used the cordless tool mainly for cutting metal closet rod, the occasional rebar, and the like, reserving more demanding jobs for the Metabo.

When JLC asked if I would like to try Makita’s new brushless 18-volt, 4 1/2-inch model XAG03, I was eager to see if it could truly replace corded grinders on the jobsite, as Makita claims. Makita sent me the bare tool (XAG03Z) along with two of its new 4-amp-hour batteries and a charger, but a full kit (XAG03M) with a plastic case is also available.


The new model is almost 2 inches longer than its predecessor, but has a narrower body that I found to be more comfortable to hold for long periods of time. Given the old model’s shorter length, however, it does fit into tighter spaces and feels a little better balanced, at least in my hands.

Internally, the new grinder really shines. In addition to an efficient brushless motor that improves battery runtime, the soft-start tool uses Makita’s “Automatic Speed Change” technology. This adjusts the speed and torque on the fly for optimal performance. Also, Makita’s “Star Protection Computer Controls” monitor the tool and the batteries help prevent overloading, overdischarging, and overheating.

To compare the cordless angle grinders side by side, I tested their runtime and speed under constant heavy load by making multiple crosscuts through scraps of 3/8-inch by 1-inch flat-stock steel. Powered by the 3-amp-hour batteries that I normally use, the older model averaged eight cuts in roughly six minutes of continuous cutting before the battery drained. Using the same batteries, the new model made the same number of cuts in only three minutes and averaged a total of 16 cuts in six minutes of continuous cutting per charge, delivering steady, constant power no matter how hard I pushed it.

When I switched to the new 4-amp-hour batteries, the new grinder averaged 22 cuts in almost 7 1/2 minutes of continuous cutting per charge. As a point of reference, I averaged the exact same number of cuts per minute with my corded grinder.

On the jobsite, I’ve used the new grinder with the 4-amp-hour batteries to cut plenty of rebar, smooth irregularities on sheet steel, ground down some humps in a concrete floor, and cut a few dozen 1/2-inch-thick porcelain tiles. I’ve only drained one or two batteries per month, so the runtime is certainly adequate for these routine intermittent tasks.

I do have a couple of gripes about the tool. I usually need to shift my grip or use both hands to lock on the slide switch for continuous operation, which is a hassle. And although I’m glad that the “Computer Controls” help prevent damage to the tool and the batteries, they can repeatedly shut down the tool when I push it really hard, which nullifies some of the convenience of going cordless.

As for power, this angle grinder is a brute. For those using a grinder for long periods at a time under serious load, though, it still won’t replace a corded model. But for remodeling contractors like me, it’s a dream come true. A paddle-switch version will soon be available.

Paul Johnson is a remodeling contractor in Portland, Ore.