Publication Date: March/April 2003
Working in concrete and masonry can be fun -- at least in theory. Knocking down a brick or block wall, drilling anchor holes in concrete, and even hogging off ceramic tile can be an adrenaline-rich, physical diversion from the office and clients. But anyone who's spent much time drilling or chipping with a big old chipping or rotary hammer knows that any novelty wears off in a hurry -- it's dirty, hard work, and the faster it's over, the better. Chipping hammers can rattle your teeth and underpowered rotary hammers waste time. And anyone who's bought two tools for chipping or drilling knows that there never was any novelty -- this equipment ain't cheap. Besides, if you end up with underpowered, undersized tools you'll get exhausting vibration while productivity drops like a stone. I know because I've been there. There's not a single project my company does that won't require drilling or chipping these materials.
Test Criteria
Whether it's chipping a high spot in a slab, drilling a thousand anchor holes, peeling tile, punching through a masonry wall, or chipping through a foundation, the tools we rely on have to be tough; 3,500-psi re-bar-embedded concrete or super-hardened 100-year-old concrete doesn't give in easily. They also have to be mobile enough to move into position when drilling horizontally or even overhead. Since most rotary hammers don't chip and since most chipping guns don't drill -- and we need both functions -- we use combination hammers. They save time, money, and even space in the gang box.
We tested seven combination rotary/chipping hammers weighing 13 pounds to 18 pounds and rated to drill a 1-1/2-inch hole in solid concrete. We looked at straight-down drilling and chipping power, maneuverability, switch design and placement, and features that make operating these tools easier. We tested the Bosch 11241EVS, DeWalt D25600K, Hilti TE 76-ATC, Hitachi DH40MB, the Makita HR4000C, Metabo BHE6045S, and Milwaukee 5315-21 by drilling in concrete as well as chipping in concrete, masonry, and ceramic tile.
Power and Speed
If a rotary hammer lacks power it'll sit in the gang box or it won't last on my jobs, so my crew and I checked power first. We equipped each tool with a new 1-1/4-inch drill bit and drilled holes 2 inches deep into concrete blocks and granite.
For straight-down (vertical) drilling, the Hilti TE 76-ATC edged out the rest of the group. At 17.4 pounds, it's a heavyweight and its mass helps. The heavier the tool, the more it counteracts the percussion inside the tool, making it almost comfortable use. We really like this because straight-down drilling is the lion's share of our work. The 18.3-pound Metabo also performed well. It has a little less power than the Hilti and a little more vibration, but it chews up concrete in a hurry.
The rest of the field (weighing from 13.6 pounds to 14.2 pounds) all performed nicely, too. They lack some of the pure power of the heavier Metabo and Hilti tools, making them slower drillers, but are still well up to the task. The DeWalt comes in next. It's a light tool, but surprisingly powerful and quick. The pack finished out with Hitachi, Bosch, Milwaukee, and Makita.
Features
Vibration Isolators. These tools vibrate a lot, impacting with 2,500 to 3,500 blows per minute. Because of this, user fatigue is a concern, especially because it can affect productivity and safety. All of the manufacturers provide cushioned side handles that help absorb the vibrations nicely.
Bosch and Milwaukee go one step further by mounting the trigger grip on rubber isolators with a hinged mount. This feature reminds me of high quality chain saw handles. These isolators noticeably reduce vibration -- if you don't push the tool too hard. If you do push too hard, you compress the rubber, minimizing its effectiveness. (Note: Pushing too hard on a rotary hammer slows the tool; back off on the pressure and let the tool do the work.)
Side Handles. A side handle is a must in this category. Not only do you need it to control the tool if it jams, but it also helps maneuver the tool, especially in a horizontal orientation like stripping tile or drilling/chipping straight ahead. Each side handle in the group has a strong, cushioned grip that enables you to hang on in relative comfort. The handle lengths vary from tool to tool. The longer grips provide a bit more leverage and more room to get your hand in the best spot for the task, but they can be awkward in tight spaces. When I took the tools to my crew, we found that handle length boiled down to individual preference with no real performance difference between them.
DeWalt and Metabo take their side handles an ingenious step forward: You can move the handles from just behind the chuck (where you normally find them) to just in front of the trigger grip. This second handle position gets both hands near each other (like on a jackhammer) while drilling or chipping straight down, which makes moving the tool from hole to hole easier and keeps you from having to bend over so far. Switching the Metabo handle is easy and still allows you to reach all of the switches when it's in the upper position. DeWalt's, on the other hand, blocks access to the mode selector switch when mounted near the trigger, which is a small nuisance.
Makita takes a different approach by providing two side handles with their tool: a straight side handle and a D-shaped side handle. The D-handle works exceptionally well for horizontal or overhead drilling/chipping because it's the natural position for your hand during this application; however, Makita doesn't recommend using it while drilling because reaction torque could be an issue: If the tool jams and your hand is stuck inside a D-handle -- look out.
Reaction Torque. When drilling in re-bar-embedded concrete, a hammer without torque control or a clutch can be dangerous. Re-bar can stop a drill bit dead in its tracks. The problem: The bit stops while the tool -- and your hands -- keep going. Thankfully, each tool in the group comes with a torque control clutch to prevent it.
Hilti's torque control is different than the rest of the group. Rather than a mechanical clutch, the tool has an electronic torque sensor called ATC, or Active Torque Control. ATC stops the tool in a split second when it electronically senses torque overload, then requires you to release and re-pull the trigger before the unit will re-start. According to Hilti, ATC stops faster than other clutch systems. Further, other clutch systems allow the bit to start spinning again after a jam if you hold the trigger on. This means the tool can stop and start in a herky-jerky fashion. Of course, despite the hundreds of holes we drilled, we didn't hit any re-bar to get a solid read on either clutch style in the test (I'm sure we'll hit five tomorrow).
Selector Switches. It seems that for machines that do two things -- chip and drill -- a speed-and-function selector switch should be an easy item to develop, but, since only a few have good switches, apparently it's not. Of all the models in the test, I like the Bosch, Milwaukee, and Makita switches the best. The chip/hammer selector switches all are in good positions, have clear graphics that indicate their function, and they engage easily. For RPM adjustments, these tools use speed dials that work fine. Hilti's switches are good, too, with a speed selector switch that toggles between 50 percent and 100 percent power. The Hilti also has a trigger lock for chipping-only that gives your hand a break from squeezing the trigger.
DeWalt's speed and function switches are decent as well. The Metabo and Hitachi switches were more awkward to use than the others. Hitachi's is hard to reach underneath the tool body while Metabo's switch has inadequate graphics, so it's difficult to know what function you're on. An experienced operator will figure it out fast enough, but I've got enough to think about without having to remember which way to flip the switch.
Bit Holders. Technically, they're called "bit holders," even though everyone calls them "chucks." Either way, these tools all use SDS max bits for drilling and chipping, and they all work well. That's no surprise, considering they're nearly identical. All of the manufacturers provide grease for the bits and holders, too.
Boxes. These tools are heavy enough by themselves. A box loaded with bits, chisels, and the tool itself easily weighs 20 to 30 pounds. Considering the amount and the weight of the iron we carry with these tools (plus the oil and a rag) a good box is necessary.
Here's my box rating criteria: For starters, any box that takes me more than two seconds to determine which side is up has a problem. In addition, a box must be durable, easy to open and close, and spacious enough for all of the accessories. All of the boxes are cast plastic and seem tough enough, except for Milwaukee's, which is metal. Hilti's box is strong and well organized, but for the life of me I can't tell up from down -- it looks identical both ends up. Milwaukee's all steel box is strong, but, invariably, steel boxes rust -- especially around concrete dust -- and without fail someone stands on them, permanently buckling the lid, which fouls the latches.
Bosch and Makita lead the pack with sensibly laid out, easy-to-use boxes; you can even tell which end is up. DeWalt and Metabo have adequate boxes, too; however, the plastic partitions inside the DeWalt box look like they could be a little sturdier.
Exhaust. Exhaust air from the cooling fans inside the tool can blow out and kick up some dust. The air exhausts through the bottom of the tool; in other words, if you're drilling straight down, it blows toward your legs. On all of the tools except the DeWalt, I could really feel their concentrated exhaust and see some dust being kicked up. The DeWalt spreads out the exhaust over a larger area; it's not as concentrated and kicks up less dust. This is a good feature, too, when drilling or chipping near the ground or in a corner.
Winners
Picking a winner here requires some serious head-scratching. The top three tools are fantastic, but different. For overall power and smooth performance -- especially straight down drilling and chipping (the vast bulk of our work) -- I like the Hilti TE 76-ATC. It's got serious power, low vibration, great switches, and the electronic torque control.
The Makita HR4000C and Bosch 11241EVS tie for second. If we did more horizontal work I'd pick up either tool in a heartbeat. The Makita isn't quite as powerful as the bigger guys, but its compactness, versatility, and dual handles are great. It's also very comfortable to operate. The Bosch drills a little faster than the Makita and is a little bigger and heavier; it has vibration isolators that really work and a good box, too. It's a well thought-out tool and comfortable to use. The list rounds out with Metabo, DeWalt, Milwaukee, and Hitachi.
Erik Elwellis a Manhattan-based contractor specializing in high-end commercial and residential remodeling.
Tools of the Trade has arranged with the companies in this test to donate their tools to Habitat for Humanity.
(Thanks to DrilTec for supplying the bits, chisels, and chipping irons for this test.)
This article is reprinted courtesy of Tools of the Trade
