About a year ago I tested nine 18-volt impact drivers. Since then, a few new models — Bosch's 25618-02, Makita's BTD 144, and Milwaukee's 2650-20 — have come on the market. This article is a review of these next-generation lithium-ion tools. My co-workers and I used the drivers on remodeling jobs and tested them for runtime. Each arrived in a kit that included two batteries, a charger, and a case.

Standard Features
The new tools are noticeably smaller than the drivers I reviewed last year — 5.75 inches long or less compared with an average of about 6.5 inches long. I consider this an advantage: Small drivers allow you to work in very tight quarters.

Like every other driver on the market, these have built-in LED lights. On the Bosch and Milwaukee tools, the lights turn on when you squeeze the trigger and off when you release it. The Makita's light is a bit different: It comes on when you squeeze the trigger and stays on for a few seconds after you release it — a feature we liked. You can disable the light by pushing a button on the base of the driver.

All three models have good belt hooks — durable, unobtrusive, and configured for use on both sides of the tool.

The Bosch and Makita have rubberized front housings to prevent them from damaging any surfaces they might bump into. The Milwaukee's housing is bare metal with screw heads protruding from the sides. If the driver slips — which in our case happened while we were installing cabinets — there's nothing to prevent it from scuffing finished surfaces.

None of the plastic cases these three tools came in had space to store the large number of 1/4-inch hex-headed attachments I like to bring to jobs. The Makita case seemed a little less sturdy than the others.

Added Features
While some features are common to all impact drivers, others are unique to a single model. On this score, Makita had the other tools beat.

Both it and the Milwaukee have fuel gauges — lamps that indicate the remaining charge. Milwaukee's is activated by a button, so it's easy to determine the remaining charge. This is helpful when you have a bunch of batteries sitting around and want to pick the most charged. The light on the Makita driver comes on when the battery is down to 20 percent, and flashes just before the battery runs out. There's no way to check the battery when it's not in the tool.

Milwaukee's charger has a two-pole pass-through plug like those found on strings of Christmas-tree lights — a nice feature that gives you an extra spot to plug something in.

If you own a cordless driver long enough, you'll eventually have to replace the brushes. This is a simple repair with the Bosch, because its brushes are easy to get to. The Milwaukee's brushes are less accessible. The Makita's motor is brushless, which makes it more durable (no brushes to repair) and efficient than a standard motor.

Among the other features unique to the Makita are an electronic speed switch — a button on the tool's base that allows the user to toggle between three hammering force settings — a glow-in-the-dark nose that makes the tool easy to find, and a trigger that prevents the battery from being accidentally discharged. The speed switch in particular is a wonderful feature.

All three impact drivers have the power to perform just about any remodeling task. I bought a 14.4-volt impact driver five years ago and the three drivers in this test blow it out of the water. However, my co-workers and I were surprised to discover that it's possible to have too much power — that a driver could be too aggressive for some kinds of finish work.

We observed this with the Milwaukee. Although it's not noticeably more powerful than the other models, its impact mechanism seems to hit harder, increasing the likelihood of cam-out. This became apparent when we were driving long Phillips-head screws into hard material. We had to be extra careful with the Milwaukee when joining cabinets together, because one slip could send the tool banging into a finished surface. This problem occurred less frequently with lags and square-drive screws.

I tested runtime by driving 1/4-inch-by- 4-inch lags into a pressure-treated 4x4 without drilling pilot holes.

The Bosch and Makita were comfortable to use throughout the test, but after about 80 lags, the Milwaukee became so hot it was hard to hold. All three tools had enough power to easily drive the lags, and with their lithium-ion batteries the power didn't decline until the last few fasteners. The Makita drove 124 lags, the Bosch 114, and the Milwaukee 102.

The Bosch came with an optional set of smaller, lighter batteries (SlimPacks), which ran a bit weaker than the standard batteries and sank only 40 lags. Milwaukee and Makita also make smaller-capacity batteries, but I didn't receive them for testing.

Cold conditions. To see how the batteries worked when cold, I left the tools in a 0°F freezer overnight with the battery portion — protected by a plastic bag — immersed in water. This created a frozen chunk of ice around the battery, which meant it would not heat up as much when I took the tool out of the freezer and ran the test in warm weather. Under these conditions, the Makita drove 95 lags, the Milwaukee 87, and the Bosch 76.

Drop test. My final test involved dropping the tools from 8 feet onto concrete. I dropped each one three times — upside-down, right-side-up, and tumbling. All survived with nothing more than minor scuffing.

The Bottom Line
The Bosch is a good tool, but nothing about it really stands out. It's powerful and compact and has an extensive rubber coating — but its nose is somewhat blunt, making it a little difficult to grab the bit-release ring.

The Milwaukee feels solid and durable, but it's heavier than other models. As a remodeler, I need a driver that can perform both rough and delicate tasks. This one hammers too aggressively for delicate work — a problem compounded by the metal nose with exposed screw heads.

The Makita BTD 144 is the best of the three. It's lighter and slightly smaller than the others and has a better runtime. For me, its many added features — especially the electronic control for managing the hammering force — clinched the deal.

Chris Kennel works for City Side Remodeling in Denver.

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