I first used a hand-held power planer when I was learning how to build wooden boats. The job required a lot of planing, which was faster and easier with a power tool than by hand. Later, when I went back to doing carpentry, one of the first new tools I bought was a 3 1/4-inch power planer. It saved time and muscle power whenever I had to plane doors or scribe cabinets and casings to the wall. It was also handy for straightening bowed joists and studs before installing the drywall.

Power planers are a lot like the jointers found in woodworking shops. Both tools can be used with or without fences and have cutter heads that are mounted between an infeed and an outfeed bed. On a power planer, the beds are referred to as shoes or bases. The blades are fastened to the head and spin on a horizontal axis.

Power planers come in a number of sizes, but the most common professional models weigh 5 to 10 pounds and have blades that are 3 1/4 inches wide.

Depth of Cut

With a hand plane, depth of cut is controlled by raising and lowering the blade. But with a power plane, it's controlled by raising or lowering the front shoe. Raising the bed increases the depth of cut by exposing more of the cutter head. When the shoes are in the same plane, the depth of cut will be zero because the blades will spin just over the surface of the stock.

The maximum depth of cut on the models I tested was just over 1/8 inch, but many tools are limited to cuts as light as 1/16 or 1/32 inch. Shallow cuts are fine if you only want to remove a small amount of stock. But if you have to remove a lot of material, it's better to have a planer that can make deeper cuts.

Scales. On most planers, you change depth of cut by rotating a knob-like grip on the front of the tool. Some of the knobs spin freely, while others click through a series of detents. Most of the tools have markings that indicate the depth of cut. About half are marked in fractions of an inch; the rest are metric. I have a slight preference for the planers with detents because once you get used to a particular tool, you'll know that popping it over to the next setting will remove a hair, or half a hair, more stock.

Indexed detents make it easy to keep track of how much material you're about to remove.

Precision. One thing that bothered me about some of the planers I tested was that the front and rear shoes didn't stay parallel to each other in all settings. If the beds aren't in parallel planes, the tool removes more stock at the beginning and end of the cut than it does in the middle. As a result, edges that are supposed to be straight end up with a hump. You might not notice it if you're planing framing, but it's a serious problem if you're doing the edge of a door.

Rabbeting. Most power planers can be used to cut rabbets. I usually make this kind of cut with a router or on a table saw, but for some reason Europeans — who design and manufacture most power planers — are really big on doing this with planers. You might use this function if you wanted to make shiplap joints, rabbet frieze boards and exterior window aprons, or mill door and windowsills.

Most power planers can be used to cut rabbets on the edge of stock. The fence is used to set width of cut, and the rabbeting stop determines depth.

The way to make this cut is to plane only a portion of the surface. If the rabbet is narrower than 3 1/4 inches wide, a portion of the base hangs off the edge of the stock. Normally, you'd perform this operation with a fence so the cut comes out straight. The width of the rabbet is determined by how much of the base you allow to ride on the stock. There's no limit to the width of this cut, but depth is strictly limited by the design of the tool. There are bearings on either end of most cutter heads, so the housing overhangs the base and will bottom out when you get to a certain depth. The maximum depth of rabbet is typically somewhere between 1/4 and 1 inch deep, with the exception of Festo's planer, which has unlimited rabbet depth.

Many power planers come with something called a rabbeting stop. This adjustable bracket screws to the side of the housing and limits the depth of the rabbet by bottoming out on the stock.

Weight, Power, and Size

Except for one of the cordless models, which was tail-heavy, none of the planers felt noticeably out of balance. The tools all handled differently, mostly because they ranged in weight from 4 1/2 to 9 pounds — a huge variation. If you're a big, strong guy or spend a lot of time planing doors and horizontal surfaces, weight shouldn't be a big issue. But if you've got a lot of miles on you, or plan on using the tool to plane vertical surfaces and cut scribes, you'll be happier with a lighter machine.

You might assume that the heavier the tool, the deeper the cut it can make. But if you look at the chart on page two of this article, you'll see that some of the lighter planers can be set deeper than tools that weigh half again as much. The choice to limit the depth of cut is made by manufacturers. In the absence of those limits, the amount of stock you could remove per pass would depend on the power of the motor, density of the wood, and width and depth of cut. A planer that has no trouble taking a deep cut off a narrow edge may bog down if you try to take the same bite across the entire width of the blade.

Length. Other things being equal, it's easier to make straight cuts with a long planer than with a short one. On the other hand, it's harder to plane to a crooked scribe line with a long tool. Porter-Cable's Porta-Plane is 16 inches long because it's designed for planing doors. Other planers are designed to perform a variety of tasks, which is why most of them are 11 or 12 inches long.

Blades

Planer blades used to be made from high-speed steel (HSS), but 10 or 15 years ago manufacturers began to make them from narrow strips of carbide. Most planers now accept the same standard inserts, or mini-blades. These inserts are 82 mm long, 5.5 mm wide, and 1.1 mm thick. Both edges are sharpened, so when one side gets dull you just flip them around in the machine. The blades cost $15 to $20 per set and are designed to be thrown away rather than resharpened.

Quality of cut. Most of the planers use two blades, so they make two cuts for each revolution of the head. A couple of planers use single blades. At 13,000 rpm, a two-blade machine would make 26,000 cuts per minute. In theory, the more cuts you make, the smoother the finish will be. But in reality, the type of blades and the speed at which you advance the tool have a greater impact on the finish cut. Equally important is how well the blades are aligned in the head.

One way to get less tear-out is to use spiral blades. Spiral cutting action is like slicing, whereas straight action is like chopping. Only two of the planers I tested use spiral cutters. The Porta-Plane has a two-blade spiral head that can be resharpened. Festo's planer uses a single disposable spiral carbide insert. Both tools make noticeably smoother cuts than the other machines.

The Porta-Plane has a two-blade spiral cutter that can be removed for sharpening.

Festo's spiral cutter uses a single removable carbide blade.

Changing blades. On most planers, the blade holders fit in slots milled in the head and are secured with bolts or Allen screws. I have a slight preference for tools that use screws because there's not much room to get a wrench on a bolt when it's in a slot.

Some manufacturers use bolts to fasten the blades directly to the head (top), while others use blade holders that fit into slots in the head and are secured with Allen screws (bottom).

A few manufacturers bolt blades directly onto the head or hold them in place with surface-mounted clamps. The blades are easy to change because the fasteners are out where you can get at them.

Alignment. A planer won't cut straight or smooth if the blades aren't aligned. Luckily, most tools are now designed to be self-aligning. Mini-blades are usually slotted so they index to the head.

The way to tell if planer blades are aligned is to unplug the tool, hold a straightedge against the rear shoe, and rotate the blades by hand. The blades are aligned if they skim the straightedge at both ends of the head. Most of these tools have alignment screws that are adjusted in the factory. When I say aligned, I mean aligned to within thousandths of an inch, so don't mess with the settings unless you absolutely have to.

Chip Ejection

On early planers, chips were always ejected from the right side of the machine. That's fine if you're right-handed and always use the tool in the horizontal position. But if you're a leftie, it means being showered with sawdust every time you use the tool. Right-handers run into the same problem planing right to left on vertical surfaces. Chips are ejected upward, and what goes up must come down.

Most current models allow you to eject chips from whichever side of the machine you want. Changing sides is simply a matter of turning a knob, flipping a lever, or in the case of one tool, reinserting a removable chute. Many power planers can be connected to shop vacs for dust collection. Some tools come with the necessary adapter; others can be equipped with optional bags or hose connectors.

Some power planers tend to bite off more than they can chew. This happens when the chute is too small to eject all the chips that are generated during heavy cutting. Your only choice is to slow down or stop every now and then to clear the chips. Either way, productivity suffers, and that's not the point of using a power tool.

Cords. When it comes to cords, longer is better. There's nothing more frustrating than to have a plug get hung up on something part way through the cut. Except for two cordless models, the planers I tested had cords anywhere between 6-ft. 8-in. and 14 feet long. The cords also varied in quality. Most power planers have rubber-like cords that are flexible at all temperatures, but the Craftsman, Freud, and Virutex planers have cords that are stiff and plastic-like.

Parking feet. Many of the planers I tried had a parking foot that swings down from the back end of the base. The foot's there so you can put the planer down without waiting for the blades to stop turning. I'd appreciate this feature more if I was new to the trade, but I've been propping my planer on a scrap of wood for so long that it's impossible to break the habit. And I have my doubts about the durability of such an exposed piece of plastic, in fact, one of the tools arrived with a broken foot.

A parking foot, standard on many planers, allows you to set the tool down without waiting for the blades to stop turning.

Fences

The fence is the most important attachment on a power planer. If you want to produce consistently square edges, you need to use a 90-degree fence. Most power planers come with this attachment, but a few have fences that can be adjusted to any angle you want. An adjustable fence is very handy for planing a bevel onto the strike edge of a door. If you do it without a fence, you end up with a crooked door or a bevel that's all over the place.

The best fences are simple, rigid, and long. Simplicity is good because it's a drag to have to search for lost parts or use a clunky contraption. Rigidity is important because it allows you to be precise. And length matters because short fences often run off the end of the stock before the blades do, and this makes it easier to botch the end of the cut.

The Porter-Cable Porta-Plane has the best standard fence. It's adjustable and runs the full length of the base. But it's not removable because the tool is specialized for planing doors. The 90-degree fences that come with the Freud, Hitachi, Makita, and the DeWalt DW680K are very simple and rigid. They're short, but you can extend them by screwing on a strip of wood. If you want, you can put a 3- to 5-degree bevel on the strip for planing doors. The 90-degree fences that come with the Festo, Metabo, Bosch 3365, and the DeWalt DW678K aren't quite as simple, but they're rigid and long enough to extend onto the rear shoe. Craftsman's planer has the simplest fence of all. It's a flat piece of steel formed to a 5-degree angle that screws to the side of the housing. It doesn't look like much, but it works. Bosch's model 3296 and Porter-Cable's model 125 come with fences that adjust to any angle. They both work, but they're not up to the level of what's on the Porta-Plane.

Favorites

If I were in the market for a general purpose planer my first choice would be DeWalt's DW680. It's light, powerful, and will make a 3/32-inch-deep cut. I also liked the Bosch 3365. It's extremely light and maneuverable, and it has an adjustable exhaust port. Another tool worth looking at is Metabo's model 0882. It's very well-made and is bigger and more powerful than many other planers.

If the only reason you want a planer is to hang doors, then the choice is a no-brainer. Buy Porter-Cable's model 126 Porta-Plane. It doesn't cut rabbets and it won't plane studs, but it's the ultimate door-planing machine.

If you need to perform specialized functions, the Festo and Virutex tools are worth a look. Festo's planer is beautifully made and has the unique ability to cut rabbets of unlimited depth. It comes with a smooth-cutting spiral head. Optional cutters allow you to produce a variety of rustic surface effects. The Virutex power compass planer is another one-of-a-kind tool. The vast majority of the world's carpenters will never need a tool like this. But if you're one of the select few who builds curved stairs or does a lot of other curved work, this planer could be just what you're looking for.