What’s the Difference: Fine-Finish Sanders: Orbital vs. Random Orbit
Regardless of the task, sanding is usually the part of the process that most of us don’t really enjoy. Having the wrong tool for the job only makes matters worse. When you’re ready to put the finishing touches on a wood project and are going the power-tool route, you’ll probably want to reach for an orbital sander—or is that a random-orbit sander? They’re different tools, and which one is right depends on what you’re looking to do. Understanding the big differences between these two small sanders will help ensure that you’ve got the right sander for the job at hand.
The telltale square foot of the orbital sander allows it to get in corners and up against edges. While it is random, the pattern created using 100-grit paper clearly shows that extra care is still needed when sanding across the grain.Photo: Rodney Diaz
The orbital sander is the older, simpler, and less expensive of these two tools. It generally has a square foot that accepts a quarter of a 9×11 sheet of sandpaper. As a result, these tools are often called quarter-sheet sanders. (There are also half-sheet orbital sanders.) To create the sanding action, the sander’s foot vibrates rapidly in tiny circles, or orbits.
The best feature of the orbital sander is its square shape, which allows it to get in corners and up against edges. You can also use regular sandpaper cut to fit rather than purpose-made random-orbit sanding disks. Orbital sanders aren’t overly aggressive, so it’s hard to remove too much material. Compared to sanding across the grain by hand or with a belt sander, they leave less obvious cross-grain marks, which means that it’s harder to ruin your work. The performance and scratch pattern differ from brand to brand, so be sure to test the sanding pattern before assuming that yours won’t leave visible cross-grain scratching.
The main disadvantage is that sanding marks are typically more visible compared to a random-orbit sander. Another drawback is that they don’t remove a lot of material. And while some designs are better than others, the clamps that hold the sandpaper in place are less convenient than the press-in-place options used for random-orbit sanders.
Orbital sanders are handy for places where a random-orbit sander won’t fit, and when only light sanding is required. They are perfect for prepping a surface for painting or sealing, or for knocking down a layer of paint. They are also useful when you’re refinishing a wood floor and need to get along baseboards and into corners.
Cost: $30 to $50
The random-orbit sander’s oscillations as it spins do not create a distinct pattern. This allows the tool to be used without concern for grain direction. When both tools are outfitted with 100-grit paper, the random-orbit sander removes more material than the orbital sander.Photo: Rodney Diaz
Now the mainstay of power sanders, this tool saw a lot of use in the automotive field before it became common for working wood. Using a circular sanding pad that’s typically 5 in. dia. (6-in. versions are also available), the random-orbit sander spins but doesn’t rotate on a single, consistent axis like a typical disk sander. Instead, the shaft spins and also oscillates off center, creating a random scratch pattern that is never exactly the same.
Due to their unpredictable pattern, random-orbit sanders create less visible cross-grain scratching. A random-orbit sander might not be the workhorse a big belt sander is, but it can remove a lot more material than an orbital sander. And many random-orbit sanders have variable-speed switches for less aggressive sanding. The hook-and-loop sandpaper disks most often found on random-orbit sanders are easier to change than the quarter-sheets clamped on orbital sanders.
The biggest disadvantage of random-orbit sanders is their round sanding surface, which makes it impossible to get in corners. Also, they can remove too much material if held in place too long. On average, they cost about twice as much as orbital sanders, but their improved performance more than makes up for the price.
When a decent amount of stock needs to be removed, a random-orbit sander is the preferred tool. It also can be used on big jobs such as refinishing a wood floor and on smaller jobs such as cabinetry.
Cost: $60 to $170
Tool-Tech Video: See what orbital and random-orbit sanders have in common and how they differ in a new video by associate editor Patrick McCombe.