Most people consider rotary tools in terms of hobby crafts. While they are particularly well suited for carving, etching, sanding, polishing and buffing, the latest generation of rotary tools has the speed, power and features to go from the workshop to the jobsite. Rotary tools accept dozens of different accessories for working virtually any building material, including wood, drywall, metal, plastic, tile, glass and stone, to name a few. These compact tools are ideal for use in extremely tight spaces and cramped quarters.

When considering a rotary tool, keep in mind that most manufacturers make a line of attachments—such as routing tables, circle-cutting guides, right-angle attachments, mini-circular saws, grinding gauges and plunge-routing bases—that greatly enhance the tool’s usefulness, versatility and accuracy.

Corded Electric Rotary Tools
It’s hard to beat the reliable power and speed of a corded electric rotary tool. The better models have electronic motors that feature feedback circuitry that maintains speed even under load. That’s important when cutting through steel rod, using a drum sander or removing rust from a metal surface. Just be sure to let the accessory do the work. Leaning on a rotary tool too forcefully could put undue stress on the accessory, motor and workpiece. In fact, that’s the hardest adjustment for most professional contractors to make: using a lighter touch. And remember, when operating a rotary tool, be sure to wear tight-fitting goggles for eye protection.

The accessories are securely held in place by a collet mounted on the nose of the tool. Most collets accept both 1/32-inch diameter and 1/8-inch diameter accessory shafts. To change accessories on most models, depress the shaft-lock button and then use the supplied wrench to loosen or tighten the collet. Some rotary tools have a tool-less changing system: Simply pull back on spring loaded slide levers to open the collet, insert the accessory and release the levers to lock the collet. 

Despite their compact size, rotary tools are super fast; many have a top speed of 35,000 rpm. Choose a model with a variable speed motor because some accessories—and some tasks—work better at lower speeds (e.g., cutting steel or plastic, using a wire brush or cutting through stone, ceramic and glass).

Cordless Rotary Tools

The main reason to buy a cordless rotary tool is freedom of movement. These lightweight, cut-anywhere tools are perfect for making small repairs and quick cuts as well as completing punch-list chores.
But freedom isn’t free. Cordless rotary tools run slightly slower than their corded cousins, have less torque, cost more on average and have a limited run time based on the battery. The good news is that the advent of lithium-ion batteries has doubled the run time of old nickel-cadmium batteries. Look for a cordless rotary tool that runs off a 12-volt lithium-ion battery; it offers a nice combination of power, run time, compactness and minimum weight.

One common use for cordless rotary tools is cutting drywall to fit around electrical boxes. Those who earn a living hanging drywall use a dedicated corded electric cut-out tool, but for those who only occasionally need to cut holes in drywall, a cordless rotary tool with a spiral-cut bit works nearly as well.

Flex-Shaft Rotary Tools
Resembling a dentist’s drill, a flex-shaft rotary tool consists of a motor that’s connected to the collet via a long, flexible shaft. It’s designed for stationary work at a bench where precision and power is required.

This style of rotary tool has a comfortable hand piece similar to a pen. It offers superior control and power for carving, grinding and shaping operations. The motor is hung on a nearby wall, and a foot pedal provides convenient control of the motor speed so the operator’s hands can remain on the hand piece.

Flex-shaft rotary tools run at slower speeds than handheld models—23,000 rpm versus 35,000 rpm—but with lower speed comes greater torque, so this type of rotary tool is much less likely to get bogged during use.

 
Construction Jobs That Can Be Tackled With a Rotary Tool

Electrical Work
  • Saw through metal conduit.
  • Rout out drywall openings for electrical outlets and switch boxes.
  • Clean rust from metal surfaces to make a safe ground connection.
  • Cut threaded rod. 
Plumbing
  • Cut copper water supply pipe.
  • Cut plastic pipe and PEX supply lines.
  • Buff off rust and mineral deposits from fittings.
  • Cut copper or plastic pipe clamps.
  • Deburr pipe ends.
  • Cut rusted closet bolts from toilets.
  • Saw through corroded hoses and hose clamps.
HVAC
  • Cut holes in drywall for vents and pipes.
  • Slice through metal hangers.
  • Saw heads off of stripped screws.

Joseph Truini is a home improvement expert and author who writes on behalf of Home Depot.