I've been a plumber and electrician so long, I could've wired Ben Franklin's key to his kite. I plumb and wire both stick and timber frames, and right-angle drills are perfect for my roughing-in tasks because they fit well between joists and studs. These brutes will drill big, deep holes in practically anything, from bone-dry double 2x10 spruce to 1-1/8-inch-thick OSB subfloor and rock-hard 8x8 timbers.
I tested medium-duty and heavy-duty 1/2-inch right-angle drills. The medium-duty tools include the DeWalt DW120K, Makita DA4000LR, Milwaukee 3107-6, and Porter-Cable 7556. The heavy-duty units include the DeWalt DW124K, Makita DA4031, and Milwaukee 1676-6 Hole Hawg.
I reviewed the tools' owner's manuals, tested for power, and evaluated speed-change, balance, and feel under load. These drills are too powerful to test in softwood, which wouldn't have yielded useful comparison results, so I upgraded to white oak timbers, which I frequently encounter in timber frames.
Out of the Box
Owner's manual. I once worked with a guy named Elvin who was drilling a ceiling joist from a stepladder when the bit jammed. The bit stopped dead, but the drill kept going -- and so did Elvin -- until I unplugged it and he dropped to the floor.
When you work with tools this powerful, it's important to read the directions. Milwaukee has the best manual in this test group. It covers all the bits we use and warns about "reaction torque," which is what happened to Elvin. The DeWalt manuals provide little spec info, nor mention anything about reaction torque. Makita's medium-duty drill manual only provides maximum diameters for two bits, while its heavy-duty drill manual is complete. However, both manuals are in metric. Porter-Cable's manual covers general safety rules, bit specs, and speed change.
Kit box. Milwaukee and Porter-Cable have the best kit boxes of the medium-duty group. Both companies provide tough cases with strong handles and clasps. Makita's is much too big for its tool. DeWalt's is made of thin, malleable plastic and doesn't seem like it will hold up for very long. All the heavy-duty drills boxes are good and tough, although Makita's is unnecessarily huge.
Drilling test. Based on manufacturers' bit specifications, I pitted all the tools against 8-inch and 15-inch white oak timbers. For each test, I put a brand-new bit on each tool and buried a 41/2-inch hole saw, a 29/16-inch self-feed bit, and bored into the timbers with 1-inch and 1-1/2-inch auger bits.
Medium-duty drills. All of these tools devoured the white oak and all cut at nearly the same speed. Each tool easily buried hole saws and self-feed bits, which means they'd easily cut holes for waste lines, vents, and wires in softwood for new construction. They'd also have no problem drilling other materials like siding or plywood. All the tools spun the bits in and removed them easily. Makita's was the smoothest, quietest drill, while the Porter-Cable tool had the most power of the bunch.
When I buried the 1-1/2-inch auger bits into a 15-inch timber, the drills finally bogged down but I couldn't get any of them to back out. Medium-duty drills' capture bolts can break if you try to reverse stuck bits. If you encounter serious timber drilling like this, you need heavy-duty units. Their gearing mechanics make them heavier, but it's well worth the weight.
Heavy-duty drills. These models are the Olympic drill team. All the tools cut at the same speed but performed differently on the 15-inch timber test. The 7.5-amp Milwaukee and 8-amp DeWalt drills labored towards the end. But the 10-amp Makita steamed through. It spun smoothly and quietly on the way in, then easily spun back out. The DeWalt and Milwaukee drills had trouble removing the auger bits.
Feel. Weight is distributed similarly on most of the medium-duty models. They're comfortable for drilling straight in, overhead, or sideways in stud and joist cavities. The Porter-Cable drill, however, is longer and heavier than the others, which makes it slightly less manageable. The heavy-duty models have similar weight distribution, although the Milwaukee Hole Hawg has the best balance and feel.
Trigger design and handle size impact how the medium-duty drills feel. Makita has the best trigger; it's oversized and parallel to the handle. Even with gloves on, you can get your hands in there without catching the trigger and there's plenty of room to engage the forward/reverse switch. DeWalt's small trigger is okay, but the bottom of the handle gets smaller and cramps big hands. Milwaukee's handle is a tight squeeze too, especially near the trigger, which sticks out too far into the handle space for me. The handle on Porter-Cable's drill allows lots of room for your fingers, but the tool would benefit nicely from a flat, oversized trigger.
Speed change. This is the most important element separating these two types of drills. On the heavy-duty tools, you flip a switch to change from low to high speed. To change speed on a medium-duty unit, you have to remove the right-angle head and flip it around, which takes several minutes.
Cool stuff. Small features like slotted chucks, detachable cords, and clutches make a big difference with these tools. Slots in the back of the DeWalt and Makita medium-duty drills' chucks afford mechanical connections to the gear systems. That removes pressure off the capture bolts when the tools are under load in reverse.
Milwaukee and Porter-Cable use a different chuck mechanism that can put too much pressure on the capture bolts and could cause them to break. I've snapped enough bolts to assure you that it's possible and it isn't fun.
I wish all my tools had a power cord like Milwaukee's Quick-Lok three-prong, replaceable power cord. Instead of rewiring a damaged cord, you simply unplug the Quick-Lok and buy a new one. The only three-prong cord in the bunch, it doesn't kink in the box and stays in the receptacle better than a standard two-prong cord.
Drilling with right-angle drills is dangerous work, which makes the clutch an important feature. If the bit sticks in the hole or jambs on a nail, the clutch kicks in and you don't get hurt or lose control of the tool. The best feature on the DeWalt DW124K drill is its clutch. It's nicely tuned and didn't engage during any of the heavy-duty drilling tests. I think all of these drills should have a clutch.
Overall, I like heavy-duty, direct-drive models best. They fit in anywhere medium-duty tools do and they carry out more work. Milwaukee's Hole Hawg is a great choice if you want a tool that's lightweight, has good power and easy maneuverability. If you're searching for pure power, Makita's DA4031 is the answer. However, DeWalt's DW124K provides the best power and mobility combination, and it has that terrific clutch.
Makita's DA4000LR is the best of the medium-duty drills. It's powerful, runs smoothly and quietly, and has a slotted chuck. I like DeWalt's DW120K. It's lightweight, powerful, has good speed change, and it's got a slotted chuck. Next is Milwaukee's 3107-6, which has good power and a great cord, but lacks a slotted chuck. Porter-Cable's 7556 is the most powerful of the medium-duty group. However, it's the heaviest of its class, lacks a slotted chuck, and has a difficult speed change.
Rex Cauldwell is a licensed contractor, master electrician, plumber, and home inspector. He lives in Copper Hill, Va.
Tools of the Trade has arranged with the companies in this test to donate their tools to Habitat for Humanity.
Thanks to Magna for supplying the self-feed bits and Lennox for supplying the auger bits and hole saws.