Tool review: Oscillating Multi-Tools
You've seen the TV infomercials where these tools tackle a variety of DIY jobs: scraping adhesive, breaking out tile grout, cutting through pipes, bolts, and drywall. We tested 10 multi-tools and found that, at times, nothing else works as well or as fast.
Whether corded or cordless, an oscillating multi-tool vibrates a blade or other attachment back and forth in a narrow arc (3-4°) at up to 21,000 strokes per minute. Because of the tool's short range of blade motion, small front-end profile, and blades that extend past the snout of the tool, it reaches into tight spots other tools can't. A multi-tool also works well for flush cutting because the stepped profile of many blades and other attachments allows the attachment to rest flat on a surface.
For woodworkers, we found the detail-sanding heads, at right, the most useful attachments. They sand small project parts and fit in tight quarters--but don't plan on smoothing a large panel with a multi-tool.
With a wood-cutting blade installed, you can make plunge cuts in the middle of a panel (top right photo) to create a cord pass-through in a desktop or cabinet back; trim plugs or splines nearly flush to a surface; and cut away sections of baseboard to install built-in cabinets. For such tasks, the aggressive teeth of the wood-specific blades cut slightly quicker than the combination wood- and metal-cutting blades, but left rougher surfaces. So we prefer the cleaner cuts, ease of control, and smoother cut edges left by the combination blades. The trade-off: burning if you get impatient and push the blade too quickly.
We were surprised to find that even when a blade jammed in a tight spot, no motor ever bogged down; instead, the oscillating motion transferred to the tool body, vibrating the operator's arm.
What to look for
Comfortable grip. Because you typically wrap one or both hands around the tool's barrel, its circumference and shape determine how well the tool fits in your hand, below. Circumferences under 7" suit small hands best. Heavier tools—some weigh up to 4 lbs—sand quickly, but are it tiring to hold during extended use.
Minimal vibration and noise. Most of the models we tested vibrated about equally, but we felt Bosch's Multi-X vibrated least. Fein's MultiMaster ran loudest when cutting, while the Rockwell was significantly quieter.
Variable speed. Slower speeds make delicate sanding jobs more manageable. Cutting and grinding work best at the highest speeds. Every tool except the cordless Craftsman 17438 offers variable-speed control. Further smoothing things out, a couple of models also feature soft-start motors that ease the tool up to speed and prevent it from jerking to the side when switching on the power
More things to look for
With as many attachments as these tools accept, swapping them becomes a common task. Fein's toolless system, shown below, takes only seconds. All others, except the Dremel models, require completely removing the retaining bolt with a supplied hex wrench. However, by using Dremel's adapter (see The Fit Can Give You Fits, below), any tool benefits from the Dremel blades' unique mounting, shown below.
Before purchasing a multi-tool, find out if the attachments your local retailers carry fit that tool. A local supplier provides more convenience, and often lower cost, than ordering attachments online.
Task lights. Because multi-tools work well in tight quarters, such as inside a cabinet, we appreciate the LED task lights found on some models.
The Fit Can Give You Fits
With so many multi-tool manufacturers, each with its own mounting system, attachments aren't always interchangeable from brand to brand. As you can see in the chart below, Dremel tools accept only Dremel attachments (unless you purchase Bosch's adapter), while Milwaukee and Ridgid accept attachments from any other maker using a provided adapter (below).
Taking a different tack, Bosch and Dremel recently introduced universal adapters (photo below). Instead of adapting the other guys' attachments to fit Bosch or Dremel tools, the adapters allow all current multi-tools to accept either the Bosch or Dremel attachments.
These tools make the cut
If you do much built-in work or installation, you'll love a tool like this. Likewise, if you have lots of general repair and renovation jobs around the house. We found these tools handy for some sanding and cutting jobs in the woodshop, too.
The tank-like construction, good dust collection, and quick-change accessory mount of the Fein MultiMaster 250Q earn it our overall Top Tool award. However, it can be a handful, literally, and requires a fine touch to get good results. The Bosch Multi-X earns Top Tool among the cordless versions. It's best for users who want a lighter, smooth-running tool with cordless convenience. The Craftsman 23465, at just $80, is our Top Value. Steer clear of the cordless Craftsman 17438. Its slow fixed speed takes longer to do jobs, and it comes with just one battery (as does the Ridgid), so you'll have to wait for a recharge.