Power Sander Primer

Typically held with one hand, some portable sanders require two hands for better control. All types (belt, orbital, random-orbit, detail) come in corded versions, with many also available battery powered. If you already own tools in a particular battery platform, it might make more sense—cord freedom!—to buy sanders that use the same batteries.

■   Belt. This handheld sander transports an abrasive belt around drums at each end of the tool. The aggressiveness of a belt sander works better for rapid material removal than fine finishing. Most use one of three common belt sizes: 3×18", 3×21", or 4×24". Belt sanders come with a dust-collection bag, but most struggle to capture the large volume of fine dust created. Overcome this by setting up a dust collector or shop vacuum with a large hood to capture dust that escapes the tool.

■  Orbital. Primarily used for finishing, these sanders have a square or rectangular pad that vibrates in tiny circles, or orbits, to abrade the wood. Sandpaper sheets mount with either built-in clamps or hook-and-loop pads. Newer models feature holes in the pads for improved dust collection, with included punch pads to create matching holes in your abrasive sheets. Orbital sanders produce smooth surfaces, but often leave swirly scratch marks that show up when you stain or dye the wood.

Tip! Replace the 5-hole pad on an older sander with an 8-hole pad from the same manufacturer; 8-hole abrasive discs are easier to find.■  Random-orbit. If you don't own any power sander, get this one first. A random-orbit sander's 5"- or 6"-diameter pad spins while simultaneously orbiting in tiny circles of ¹⁄₈ " or less. These combined actions help blend the scratch patterns, so that by the time you sand through 180 or 220 grit, the scratches become almost invisible.

The pads of most sanders in this class have eight dust-collection holes, and the abrasive discs on the market match them perfectly. The included bag or canister filter provides good dust collection, but for even better performance, attach a fine filtering shop vacuum. If possible, choose a random-orbit sander with variable speed so you can choose the best speed to match the workpiece and abrasive grit. A few models offer dual modes, letting you choose between a fine-finishing, smaller orbit and a larger, more aggressive orbit for rapid removal.

■   Detail. A cousin of orbital sanders, these tools use smaller triangular or rectangular pads for sanding into corners and tight spaces. They remove material well, but it can be difficult to blend their scratch marks with those made by another sander. We view detail sanders as a tool of last resort, when no other will do the job. (Sanding project parts prior to assembly helps avoid the need to sand into tight corners.)

Tip! Clamp one of these tools to a workbench for a small, but effective, spindle sander with a tiny table surface.■  Oscillating spindle. If you don't own a benchtop or floor-standing model, this handheld version works well for sanding curved edges. You'll find only a couple of models on the market (Grizzly and MLCS Woodworking). They come with four drums and abrasive sleeves (¹⁄₂ ", ³⁄₄ ", 1", and 1¹⁄₂ " diameters), providing a good solution for most curves.

■  Drum sander. This tool's drum holds an abrasive sleeve that can dish out wood quickly if you don't keep it moving. We know of two models (Makita and Porter-Cable Restorer); both have accessory heads available with wire or nylon brushes for (purposely) scratching the wood to add texture or simulated age, or for cleaning up actual barn siding or similar wood. You can also buy paint-removal drums. As you'd expect, these generate a lot of coarse dust, so connect to a vacuum to minimize the mess.

Most of these machines come in both robust floor-standing models and benchtop versions that cost less and typically have smaller worksurfaces and motors.

■  Disc. Many disc sanders for home shops have 12"-diameter discs, but a few smaller and larger models exist. A self-adhesive abrasive disc sticks directly to the tool's metal platen, which excels at creating square, flat edges. Because you can work only on the downward-spinning portion of the disc, it provides a limited working surface, and you can sand only flat or convex surfaces. Look for a disc sander with a large, sturdy table, preferably made of cast iron; a miter slot proves helpful for holding jigs and accessories.

■  Belt/disc combo. These machines have a single motor that powers the belt and disc at the same time. The belts come in 1–6" widths, and the discs from 6" to 12" in diameter. Like a dedicated disc sander, these machines primarily sand flat and convex surfaces. But some models allow you to use one of the belt drums for sanding concave surfaces. The belts excel at sanding long straight edges, such as tapered table legs or box sides.

■  Drum. A drum sander's wide abrasive-wrapped drum spins parallel to the machine's power-driven feed belt. Because the abrasive wraps spirally around the drum, it requires special-shaped and -sized abrasive rolls. You can sand the faces of a workpiece or assembly (raised-panel door, picture frame, etc.) to a specific thickness, flatten a glued-up panel, or simply remove milling marks. The drums measure 7–18" wide in open-ended models, but you can double the capacity by rotating the workpiece end for end and sanding the other half to the same thickness. Closed-end drum sanders, such as the one shown, limit workpiece width, but virtually eliminate drum deflection or sagging.

■   Oscillating spindle. Nothing beats one of these machines—with a sanding drum that raises and lowers while spinning—for sanding inside curves. Benchtop models usually include at least four drums of different diameters; floor models often provide 6–8 drums. They usually come with 80- or 100-grit abrasive sleeves for the drums, with finer grits available as accessories. Taller spindles (8–10") provide more working surface for thick or wide workpieces. Heavy-duty spindle sanders have an oil-bath gearbox for a quieter, longer life.

.■   Oscillating edge. Think of this as an oversize horizontal belt sander with the up-and-down action of an oscillating spindle sander. This action extends the life of the abrasive belt, while also blending the scratch pattern. An edge sander works great for smoothing long straight edges, such as table legs and spindles. You can also shape concave edges at the end on one of the drums, usually requiring the removal of a guard.