In woodworking, a tremendous amount of sanding is often necessary to finish off a project. Consequently, a wide array of sanders have been developed to accomplish the different kinds of sanding necessary to remove layers of wood or finish from a piece. While a belt sander is useful for removing a significant amount of material by means of a fast-moving sandpaper belt that moves rapidly in one direction, an orbital sander removes less material at one time and uses a random orbital pattern to prevent deep grooves and scratching.
An orbital sander is powered, either by a battery pack or by a cord plugged into a wall outlet. It is hand-held, and depending on the size, the orbital sander may be very small--as is the case with a palm sander--or larger, as is the case with a right angle or in-line model. A palm orbital sander is best for small jobs such as molding or drywall. A right angle orbital sander is much heavier-duty, and is useful for large projects that require extended use. An in-line orbital sander is a compromise of the two and has handles on either side of a body mounted above the sanding unit to allow for solid control.
Each type of orbital sander mentioned works in the same manner: a pad attached to the unit moves in an orbital pattern while the sandpaper itself moves in a circular motion. This unique motion means the grit on the sandpaper will not pass over the same spot twice, preventing gouging or swirling on the finished product. Because the orbital sander takes off only a small amount of material at a time, it will produce a smoother finish than, say, a belt sander, which will take off a large amount of material and create gouges.
An orbital sander is not necessarily limited to woodworking projects. They can be used on metal as well, but for such applications, a different type of sandpaper must be used. In any application, be sure to research several different models before purchasing one. Look for an orbital sander that features variable speed, full ball bearing construction, a metal or strong plastic body, and a dust collection system. Be sure to consider the method by which each sander secures sandpaper to the machine; some systems are better than others, so be sure to decide which one works best for you. As is the case with any machine that removes material, a dust collection system is vital to prevent harmful materials from entering your eyes, mouth, and nose. Wear safety glasses while using an orbital sander.