Milwaukee's M12 line is the largest and most diverse 12-volt lithium-ion platform available. It includes everything from a palm nailer and plumb laser to a fork meter and PVC shear, not to mention the subcompact drill/driver I tested last year ("12-Volt Drill/Drivers," 6/11). Now there's an M12 jigsaw, too. It's sold as a bare tool for those who have already invested in the platform, or as a kit with a compact battery and a charger. Since it's the first subcompact model on the market, I wondered if it would have enough power, speed, and runtime to replace my battle-tested Bosch corded jigsaw. I spent several hours with the kit to see how it stacks up.
The M12 weighs just 4.3 pounds with the battery installed and pumps out 0 to 2,800 strokes per minute (SPM) with a 3/4-inch stroke length. By comparison, the latest professional 18-volt lithium-ion models weigh 5.3 to 7.8 pounds and deliver top speeds ranging from 2,200 to 3,000 SPM with a 1-inch stroke. Current corded pro models weigh 5 to 6.4 pounds and deliver top speeds from 2,800 to 3,100 SPM, also with a 1-inch stroke.
But the SPM ratings say little about the comparative cutting speed of the M12. For one thing, the M12's abbreviated stroke pushes fewer saw teeth through the material. For another, SPM refers to no-load strokes per minute. Start cutting, and the larger and stronger motors in the other models tend to maintain a higher cutting speed than the M12's compact motor. For instance, although Milwaukee's M18 18-volt jigsaw tops out at just 2,200 SPM with a 1-inch stroke, Milwaukee reports that it cuts about 33 percent faster in the nonorbital mode than the M12.
The M12 has several deluxe features, including a keyless shoe that tilts 45 degrees both ways with a stop at 90 degrees, a tool-free Quik-Lok T-shank-blade clamp controlled by a lever so you don't have to touch hot blades, a trigger-activated LED headlight that stays on for about 10 seconds after you release the trigger, and an LED battery gauge that stays lit for about two seconds after you pull the trigger.
On the downside, the tool doesn't let you switch to an orbital mode for coarser but faster cutting and doesn't have a blower to help clear the cut line. Like other cordless jigsaws, it also lacks a trigger lock-on button.
What really distinguishes the M12 is its vertical power plant and "Hybrid Grip." The motor in conventional top-handle and barrel-grip models nests horizontally inside a barrel-shaped housing directly behind the gearbox. For the M12, Milwaukee stood the motor up and moved it forward beneath the gearbox so most of the weight rests on the cutting area, dampening vibration. This configuration allowed Milwaukee to replace the traditional fat motor housing with a slender handle that's essentially an ergonomic barrel grip equipped with the type of variable-speed trigger previously found only on top-handle models. The grip is close to the work surface for maximum control when cutting curves, and the variable-speed switch lets you conveniently change speeds on the fly. The hybrid grip also holds the battery.
To gauge the battery runtime, I installed a 6-tpi Bosch T144D Speed for Wood blade and made straight cuts in 1/2-inch and 3/4-inch Douglas fir plywood, running the test twice in each panel and averaging the results. The tool cut over 33 feet in the 1/2-inch panel and over 19 feet in the 3/4-inch panel. You can double the runtime by using Milwaukee's XC high-capacity battery instead, which costs an extra $70.
I also used Bosch blades to cut a sink opening in a laminate countertop, notch Armstrong laminate flooring, cut outlet openings in 1/8-inch paneling, cope pine crown molding, complete the cutouts in 2-by Douglas fir stair stringers, make plunge cuts in 3/4-inch oak plywood, and notch sheet metal. Turning up the heat, I tried to trim 4/4 oak and poplar to fit against a wavy surface, notch 1 5/16-inch Tamko EverGrain composite decking, cut decorative curves in 2-by Douglas fir rafter tails, and plunge-cut the fir.
The M12 accomplished all of these tasks, but it had an obvious comfort zone. It easily cut the laminate flooring, paneling, plywood, and sheet metal, and could turn on a dime. To cope crown molding with a jigsaw, you normally hold the tool upside down and cut from behind the stock. I was able to do that with the M12 by squeezing the trigger with my thumb. According to Milwaukee, the tool also accepts the dome-shaped aftermarket Collins Coping Foot that's popular with finish carpenters. I wish I could have turned off the headlight while coping, because it shined right into my eyes. It also can create unhelpful glare on glossy or bright surfaces.
In a pinch, I wouldn't hesitate to cut a sink opening with the M12, but jigsaws with orbital action can be much faster. With a Bosch T308B blade, for instance, the M12 cut my laminate countertop sample at about 21 seconds per foot. My corded model with full orbital action did it in about 11 seconds per foot. The M12 easily finished the stair-stringer cutouts.
As for ripping the 4/4 hardwood, the tool was painfully slow and I was only able to cut 4 lineal feet on a charge. It also cut the composite decking slowly. It cut and plunge-cut the 2-by lumber reasonably well, but if I planned to do that often, I'd buy an XC battery for extended runtime. I'd rather use my corded model for that, though, because of its orbital option.
I did encounter one problem: The tool I tested aimed the blades slightly to the right, which sometimes forced me to skew the tool to follow my cut lines. I confirmed this problem by trying to guide the tool with a straightedge; the tool veered away from the straightedge when cutting from left to right, and the blade itself bent toward the straightedge when cutting from right to left.
The Bottom Line
Overall, the subcompact M12 exceeded my expectations. I was surprised it would even cut 2-by material, for instance, and it sailed through the thin stuff. In use, I forgot all about its unique hybrid grip, which must mean I like it. I also appreciated the easy blade changes and bevel adjustments, the battery gauge, and the roomy contractor bag. But as a finish carpenter I make lots of jigsaw cuts, including ones in thick hardwood, and I'm used to pulling out my old corded Bosch, quickly deciding whether I need a certain degree of orbital action, donning a dust mask if necessary, locking on the trigger for long cuts, and letting the saw's blower clear the cut line. That's not possible with the M12.
Would I buy the subcompact if I had other M12 tools and didn't own a jigsaw? Given that even the bare tool costs $120, the answer is no. I'd buy a corded model. But your needs may differ, and the M12 might meet them.
Bruce Greenlaw is a JLC contributing editor.