Choosing and Using a Random-Orbit Sander

Palm sander
For small projects, such as stripping furniture or sanding a drywall patch, a palm sander is tough enough to do the job but easy on the wallet. These little machines get their power by orbiting quickly—at least 10,000 times per minute. Compact and light, they can be held either over the top or around the neck, whichever is more comfortable.

Right–angle drive
With a houseful of millwork and cabinets to finish, you'll need a sander that can work all day without overheating. A right–angle machine, with its horizontal, barrel–style body, runs a powerful 3.5– to 5–amp motor at a relatively slow (and cool) 5,000 orbits per minute. Higher–priced units have precision bearings and better gears that vibrate less and last longer.

In–line drive
When you face a lot of sanding but don't feel comfortable with a big right–angle machine, try a unit whose motor sits above the pad. It's a good compromise between small palm sanders and beefier models, especially for people with small hands, who can grab the handles fore and aft instead of having to grip a right–angle's body.

Hook–and–loop disc
Abrasive discs that attach by a Velcro–like hook–and–loop system allow you to change grits without trashing any disc before its time. They're more expensive than adhesive discs, but more economical in the long run because they can be reused. Be sure to match the disc's dust–collection holes to the ones on your machine's pad.

Variable speed
You want your sander to remove material quickly, but not so aggressively that it chews through thin veneers or delicate coats of finish. The solution is variable–speed control. To get the most out of this feature, choose the tool with the widest range of speeds. A soft–start option, which lets the machine ramp up gently to full power, also helps protect tender work.

Starting and stopping
To avoid scuff marks, Norm Abram always plants the disc on the surface before he starts the motor and lifts it off the work before shutting down. However, some sanders lurch hard when starting, which is liable to dig a deep (and annoying) divot; with those tools, it's better to start in the air and then land flat on the work with the motor running. Experiment on scrap wood to see which approach works better with your machine.

Sanding flat surfaces
Glide the machine across the surface, working from side to side to so you're sure to sand everywhere without dwelling too long anywhere. Norm likes to sand the whole surface across the grain, then diagonal to the grain, then with the grain before changing to a finer grit. Keep the machine moving, but don't press hard or "scrub"—the sander's own weight, plus your gentle steering control, is most efficient and effective.

Sanding edges
Lift the sander off the work when you want to move from a flat surface to an edge. If you flop it over, you'll sand off the crisp corner. Center the edge on the pad and use both hands to help keep the pad square to the wood. A detail sander, which orbits without rotating, is an easy tool to guide along an edge.

Cleaning up
Because of the sander's motion, any stray grain of dust left on a work piece can cause deep scratches. Since even the best dust–control system will leave some particles behind. Norm advises vacuuming the work after each sanding and following with a tack cloth.