A planer is a woodworking tool that shaves wood to a uniform thickness and smooth surface. Its core job is taking rough, uneven boards and turning them into flat, consistent stock you can use for furniture, cabinets, shelving, or any project that requires precise dimensions. Whether you’re working with lumber straight from the sawmill or cleaning up old barnwood, a planer is what gets your material ready to build with.
How a Planer Works
A thickness planer feeds a board across a flat table and past a spinning cutterhead that shaves material off the top surface. Rollers grip the board and pull it through at a consistent speed, while the cutterhead removes a thin, even layer. You set the desired thickness, and the machine does the rest. The result is a board with a smooth top face that’s parallel to the bottom face, uniform from end to end.
This matters because rough-sawn lumber is rarely flat or consistent. A board from the lumberyard might vary by an eighth of an inch or more across its width. A planer eliminates that variation, giving you stock that fits together tightly in joints, glue-ups, and assemblies.
Common Uses
The most frequent use is simply thicknessing boards. If you buy rough lumber (which is cheaper than pre-surfaced wood), a planer smooths both faces and brings the board to the exact dimension you need. Need a half-inch panel for a drawer bottom? Run a thicker board through the planer repeatedly, lowering the cutterhead a little each pass, until you hit your target.
Planers are also essential for reclaiming old wood. A piece of 100-year-old barnwood with nail holes, dirt, and a weathered surface cleans up beautifully after a few passes. The same applies to pallet wood or any salvaged lumber. The planer peels away the damaged outer layer and reveals fresh, usable material underneath.
Beyond that, planers help you match thicknesses across multiple boards. If you’re gluing several boards into a tabletop, they all need to be the same thickness or you’ll spend hours sanding. A planer gets them identical in minutes. This process of milling rough lumber flat, square, and uniform is the foundation of furniture building, cabinetry, and most serious woodworking projects.
Planer vs. Jointer
This is one of the most common points of confusion. A jointer creates one perfectly flat surface by removing high spots. It references off its own flat table, so it can take a warped or cupped board and make one face truly flat. A planer does something different: it makes one face parallel to the opposite face. The board rides on the table with its bottom face down, and the cutterhead shaves the top face to a consistent distance from the bottom.
This distinction is important. A thickness planer cannot flatten a warped board on its own. If you feed a cupped board through a planer, the rollers press it flat momentarily, the cutterhead takes a uniform cut, and then the board springs back to its cupped shape. You’ve made it thinner, but not flatter. That’s why many woodworkers use a jointer first to flatten one face, then flip the board and run it through the planer to make the second face parallel. Together, the two tools give you perfectly flat, uniformly thick stock.
Types of Planers
A benchtop thickness planer is the most common type for home workshops. These are portable machines, typically handling boards up to 12 or 13 inches wide. A popular model like the DeWalt DW735 accepts boards up to 13 inches and runs on a standard 15-amp household circuit. For most hobbyists and even many professionals, a benchtop planer handles the majority of everyday work.
Stationary floor-standing planers are larger, heavier, and built for production shops. They handle wider boards, take heavier cuts, and run for longer periods without bogging down. Unless you’re running a professional operation or routinely working with wide slabs, a benchtop model is the practical choice.
Handheld power planers are a different tool entirely. They work more like a portable jointer, shaving material from one spot rather than thicknessing an entire board. They’re useful for trimming a door edge, creating a bevel, or shaving down a high spot, but they can’t produce the uniform thickness that a stationary planer delivers. A handheld planer gives you a flat surface in one area, not a board that’s parallel and consistent across its full length.
Straight vs. Helical Cutterheads
Most budget-friendly planers come with straight cutterheads: a rotating shaft with two to four long, flat blades. These work fine for general use, but they have drawbacks. Each blade contacts the wood all at once across its full width, creating noticeable cutting resistance and vibration. Over time, straight blades dull faster (especially on hardwoods), and they’re more likely to leave visible cutter marks or tear-out on figured or soft wood.
Helical cutterheads use dozens of small, square carbide inserts arranged in a spiral pattern along the shaft. Instead of one long blade hitting the wood all at once, these inserts engage one at a time in a shearing motion. The result is a smoother surface, less tear-out, significantly less noise, and reduced vibration. The inserts also last much longer than straight blades. When one edge dulls, you simply rotate the insert to expose a fresh cutting edge. Helical cutterheads cost more upfront, but many woodworkers consider them a worthwhile upgrade, especially if you work with hardwoods or figured grain regularly.
Dealing With Snipe
Snipe is the single most common frustration with thickness planers. It’s a slightly deeper cut at the first and last few inches of a board, leaving those sections a hair thinner than the rest. It happens because the board is only held by one roller (instead of two) as it enters and exits the machine, allowing the end to lift slightly into the cutterhead.
Several tricks minimize or eliminate snipe. The simplest is lifting gently on the trailing end of the board as the front enters the cutterhead, and lifting the leading end as the board exits. This keeps the board pressed flat against the table during those vulnerable moments. Another approach is feeding a sacrificial scrap board directly in front of and behind your workpiece, with no gap between them. The extra pieces keep roller pressure even across the transition.
For a more permanent fix, you can attach support rails (strips of wood about a foot longer than your workpiece but the same thickness) to either side of the board. These extend past both ends, ensuring the rollers always have something to grip. And if none of that appeals to you, simply cut your boards 4 to 6 inches longer than needed and trim off the sniped ends after planing.
Grain Direction and Feed Safety
Always feed wood into a planer in the same direction as the grain. Running a board against the grain, or feeding end-grain through the machine, risks dangerous splitting, chipping, and kickback. If you’re not sure which direction the grain runs, look at the edge of the board. The grain lines typically angle slightly, like the slope of a hill. Feed the board so the cutterhead is cutting “downhill” along that slope.
Beyond grain direction, never plane boards that are too short (most machines have a minimum length, typically around 12 inches) or too thin for the machine’s specifications. Pieces that are too small can get caught by the rollers and shot out or shattered. Check your planer’s manual for minimum dimensions before feeding anything through.
What About Metal Planers?
Metal planers exist but serve a completely different purpose. Industrial metal planers shave flat surfaces on large castings and heavy steel parts. They used to be common in machine shops, though they’ve largely been replaced by milling machines for most tasks. You’ll still find them in specialized shops that work with oversized raw castings. If you searched “what is a planer used for,” you were almost certainly looking for the woodworking tool, but it’s worth knowing the metalworking version exists if you encounter the term in an industrial context.