Oil-pulse Impact Drivers
If you've ever used an impact driver to drive screws, you have an appreciation for its tremendous torque, typically 3–4 times more than a comparable drill/driver. Impacters tend to be lighter and smaller than drill/drivers—more reasons to love them. But their loud clattering noise can drive you crazy, especially when working in tight surroundings, such as when hanging wall cabinets or installing a countertop onto a base cabinet. But now there's a quieter alternative: oil-pulse impact drivers.
We tested four battery-powered oil-pulse drivers head-to-head, and ran a traditional cordless impact driver (the Makita XDT12Z) through the same tests for comparison.
How they work
A typical impact driver uses a spinning hammer-and-anvil mechanism to in-crease rotational torque. (See illustration below.) The more demand a fastener puts on the tool, the more torque the hammer and anvil attempt to apply by slamming together. It's this metal-on-metal action that creates the loud noise and vibration.
An oil-pulse driver uses a different hammer-and-anvil mechanism, encased in a module containing gear oil. Rapid, pulsing movement of this fluid operates the hammer and anvil, which make contact for a longer, but slower, duration to create quieter impacts (compared to regular impact drivers). And manufacturers tell us this "cushioned-impact" system helps prolong tool life.
Power exceeds rated torque
With each tool, we drove three sizes of wood screws and lag screws up to 31⁄2 " long in Douglas fir lumber. The Ridgid Stealth Force demonstrated the most power among the four oil-pulse drivers, performing about equal to the traditional-impact Makita XDT12Z, despite being rated as having half as much torque. (See the chart.) The Milwaukee Surge driver ranked as second most powerful among the oil models, followed by the Makita Oil Impulse and the Ryobi Quietstrike, respectively. Despite the differences, each of these oil-pulse impact drivers produce all the torque you'll likely ever need in your shop, as well as when you build that new deck, pergola, or garden arbor.
A substantial noise and vibration difference
The oil-pulse drivers consistently created 5–8 fewer decibels of noise in our testing, compared to the traditional impact. That's a noise level one-half to one-quarter that of traditional drivers. Compound that noise reduction over a day or more, and you'll greatly appreciate these new tools.
In addition, oil-impulse drivers vibrate noticeably less than traditional impacts. Even after driving a few dozen fasteners, we experienced none of the hand and arm tingling that normally results from using a traditional impact driver. The Ridgid driver, like the others, did not show excessive vibration, but under heavy load tended to wobble significantly.
More helpful features abound
■ Battery power. All four oil drivers run on battery packs compatible with each brand's existing 18-volt line. All but the Ridgid sell as bare tools, saving you money if you already own that brand's battery packs and charger. Each model except the Makita also sells in a kit with batteries and charger.
■ Multiple speed ranges. The Makita, Milwaukee, and Ridgid drivers offer at least three speed-range settings, letting you select the best range for the fastener you're using. A fourth setting on the Makita and Milwaukee drivers (shown below) starts self-tapping screws at a fast speed until the threads grab, then the tool automatically reduces the speed to seat it without stripping. All the drivers have variable triggers, so you can control the speed within each range by feathering the trigger.
■ Brushless motors. The Makita and Milwaukee drivers have brushless motors that allow for a smaller overall size. The Ridgid, though also with a brushless motor, comes in a bulkier body as a result of its larger oil-pulse module.
■ Quick-connect chucks. Each of the four oil drivers has a 1⁄4 " hex chuck that features one-hand bit installation, meaning you don't have to retract the sleeve (as when removing bits). All the chucks performed well.
■ Light the work. All four drivers illuminate the area in front of the chuck with LEDs. The Ridgid and Ryobi provide the best lighting, shown below, but Ryobi's trigger must be depressed to activate the light. A switch on the Ridgid's handle activates the LED, which stays on about 10 seconds after releasing this switch or the trigger. The Makita and Milwaukee drivers use a single LED just above the trigger that creates shadows around the fastener during use.
The bottom line
Although we appreciate the Ridgid Stealth Force's torque, its large size and weight negate a couple of key reasons we like an impact driver in a woodshop. The Makita Oil Impulse and Milwaukee Surge performed similarly in our tests, without the bulk of the Ridgid. Because it was so close between these two—Milwaukee had slightly greater torque, but the Makita was a little quieter—they share our Top Tool honor.
Makita Oil Impulse XST01Z, $180 (bare tool)
Milwaukee Surge 2760-20, $150 (bare tool)
Ridgid Stealth Force R86036K, $200 (kit)
Ryobi Quietstrike P290, $80 (bare tool)
Download PDF of Oil-pulse Driver Chart