No-fail Routines for Jointing and Planing
Because they work in a similar fashion to remove stock from the face or edge of a board, the roles of the jointer and planer often cause confusion. Both help flatten and square up lumber, but they have distinct and different jobs. A jointer flattens one face of a board and squares up an adjacent edge—but it can't bring that board to consistent thickness. That's the planer's job. So a jointer and planer work together, much like love and marriage in the old song: You shouldn't have one without the other.
Flat, square stock begins on the jointer, so let's start there.
Jointing: a fundamental step for woodworking success
How a jointer works
As you can see in the Jointer Cutaway [below], infeed and outfeed tables straddle a cylindrical cutterhead. The infeed table sits just lower than the top arc of the knives; the outfeed table sits flush with the top arc.
As you feed a workpiece into the cutterhead, the knives remove any portion of the board below the plane of the outfeed table. The jointed surface then passes smoothly onto the outfeed table. Each successive pass removes more wood until the cutterhead flattens the entire surface of the board.
First, joint a face
Before jointing a board, sight along an edge to spot any bow or cup [below] and to determine the grain direction.
For the best results, feed the board across the jointer with the bow up so the board rides on its ends, cup facing down, and the grain running downhill from left to right [shown in detail drawing above].
If the grain runs uphill, the cutting motion may follow the grain up into the board until small pieces break off. That's chip-out.
To face-joint the workpiece, set the infeed table for a cut of 1⁄16 " deep or less. Rest the board on the infeed table, behind the cutterguard. Using pushblocks, move the board forward with just enough downward pressure to keep it in contact with the infeed table [below]. Use most of your force to feed the board forward, not press it downward. Too much pressure flattens the cup or bow from the workpiece, only to have it return as soon as you lighten up.
After about 6" crosses the cutterhead, move your left hand—and pressure—to the outfeed end of the workpiece [below]. Move the piece forward with both hands, applying light pressure to keep the jointed portion in contact with the outfeed table.
As the board reaches the end of the cut, move your right hand to the outfeed side and keep pushing the workpiece past the cutterguard to complete the cut [below]. Reposition your hands as needed to press the jointed portions of the board onto the outfeed table.
You don't want to remove any more stock than necessary, so to track your progress, scribble a chalk line across the face to be jointed. If a piece has a pronounced cup or bow, the knives won't remove much material on the first pass [below]. With repeated passes, though, the board gets flatter as the jointed surface grows larger. When the chalk line disappears, the face is flat.
As you machine stock, it can be hard to keep track of which face is flat and square to which edge. So after your last pass, mark the newly machined surface. Traditionally, cabinetmakers draw a curlicue on the jointed face, and a caret, or inverted "V", on the adjacent squared-up edge, with the point directed to the flattened face [below].
Next, square up an edge
After flattening one face, the jointer makes easy work of squaring up an adjacent edge. Follow the same procedure as for jointing a face, with one addition: Firmly press the jointed face against the fence while feeding the board as before [below].
If possible, orient the grain direction down and away from the cutterhead rotation to prevent chip-out [Drawing above].
Mark the squared-up edge as shown above. Then, with one face flat and one edge square, move on to the planer.
Planing: Create stock of any thickness
How a planer works
Unlike a jointer, a planer's cutterhead sits above the workpiece parallel to the table [below]. Lowering the cutterhead between passes reduces the board to a uniform thickness.
At the planer, you don't control the workpiece during the cut. Instead, feed rollers on either side of the cutterhead push down on the workpiece while pulling it through the machine. That's why it's important to joint one face first: Without a flat face to ride against the planer tables, the feed rollers simply press the board flat against the tables while the knives plane the top face. Any cup, bow, or twist springs back once the board exits the planer.
Again, consider grain direction when feeding stock into the planer. But remember that the planer cuts from the top, so the rules are reversed. To reduce chip-out, orient boards with the grain running uphill toward the back end [Drawing above].
Removing 1⁄32 " of material or less per pass also reduces chip-out. If you have a two-speed planer, shift to the slower feed rate for final passes to get a smoother surface. Set the depth of cut for a 1⁄64 "-or-less "skimming cut" on the final pass for the same reason.
Lighter passes also decrease snipe—a divot at the start or end of a cut. To further decrease or even eliminate snipe, use your hands or support stands to keep a long board flat to the tables at the beginning and end of the cut. For short boards, glue on temporary runners, and rip them away after planing [below].
For boards that require removing 1⁄8 " or more to reach final thickness, after planing the top face flat, flip the board, and plane the jointed face. Continue alternating sides until reaching final thickness because removing similar amounts of stock from each face keeps the board stable, reducing warping.
Still having problems? You might need to adjust
If you religiously follow all of the pointers in this article, yet still don't see good results when jointing or planing, your machine may be out of adjustment. All of the proper technique in the world won't fix that. If you suspect something's amiss with either machine, we have some solutions for your planer and your jointer.
- Reduce waste and increase yield by cutting boards to rough length and width before jointing. Less bow on the shorter, narrower pieces means fewer passes to flatten the board [below].
- Get a smoother face and reduce chip-out by removing 1⁄32 " or less per pass. A slower feed rate gives a smoother surface, too.
- Joint a twisted piece by applying pressure on opposite corners [below]. Concentrate on keeping those corners flat on the tables and not rocking the workpiece as it passes over the cutterhead. After making a few passes, the flattened corners provide a stable surface for the piece to ride on as you joint the remainder of the face.
- When jointing two pieces that will be edge-glued together, joint one piece with the bottom face against the fence, and the other with the top face against the fence [below].
If the fence is slightly out of square to the table, the two angles offset each other, and the glued-up panel will be flat [below].
- Face-joint stock wider than your jointer bed by ripping the board in half, jointing each piece, including the ripped edges, and then edge-gluing the pieces with the jointed faces flush. Rip badly cupped, crooked, or twisted stock on the bandsaw.
- Use a dust collector to remove waste from the planer. Chips or debris caught between the workpiece and the feed rollers or tables can dimple the board.
- Grain patterns sometimes change direction, and some species (such as maple) are just prone to chip-out. To reduce chip-out, feed the stock at a slight angle [below] . This also evens out wear across the length of the knives.
- To plane stock less than 1⁄4 " thick, double-faced-tape it to an MDF carrier [below]. But don't plane stock to less than 1⁄8 " thick. The knives can splinter the piece and shoot debris back at you.
- To bring several boards to identical width, without the blade marks you might get from a tablesaw, stack several pieces face-to-face on their jointed edges; then feed the stack through the planer [below]. Use this method only with stock thicker than 3⁄4 " and a stack that is thicker than it is wide.
Watch these techniques in action in this video: