Edge Jointing

Comments (0)

This article is from Issue 13 of Woodcraft Magazine.

Perfecting edge joinery is a necessity for contemporary woodworkers who are finding that boards come in smaller sizes these days.

By Kerry Pierce

In a perfect world, if you needed a 36"-wide cherry board for the top of your dining table, you would go to the local lumberyard and select from a stack of 36"-wide cherry boards, all cut from trees measuring 60"-70" in diameter. But in this world, if you asked a yard hand at your local lumberyard where they keep the 36"-wide cherry boards — well, I can only imagine the reaction you might get.

Several years ago, when I needed 18"-wide cherry boards for a Queen Anne highboy, I had trouble finding good 10" boards I could glue up in twos. And often we find ourselves gluing up panels measuring only 8-10" from even smaller stock. This reflects the changing nature of American hardwood forests. Instead of taking mature trees with breast diameters of 40" or more as their predecessors did, contemporary foresters are harvesting much smaller specimens. This makes the edge joint perhaps the most important of woodworking joints for the contemporary craftsman.

Sometimes edge joints are reinforced with cross-grained splines or biscuits. These mechanical aides primarily assist with alignment, although they do provide some strength and a modest amount of additional glue surface. Edge joints are also sometimes formed using tongue-and-groove cutters. This approach is most often used for unglued joints, such as when you’re butting together stock for a floor or for a cabinet back. 

Typically, however, the cabinetmaker uses a simple butt joint held together with a good adhesive, and — despite their inglorious name — when properly formed, butt joints are extremely strong, sometimes stronger than the wood adjacent to the joints. 

Forming the joint with a machine

One of the simplest things you can do to improve your edge joints is to check the tables of your jointer for proper alignment. Lower the infeed table until its top surface is approximately 1/8" lower than the outfeed table. Lay a long straightedge across both tables. Its bottom edge should rest on the surface of the outfeed table and sit 1/8" above the surface of the infeed table. 

Check to see if there is a consistent 1/8" gap between the bottom of the straightedge and the top of the infeed table along its entire length. You should also check to see that there is a consistent 1/8" gap across the width of the table. If there is any variation, check the owner’s manual for information on how to rectify the error. 

This is a check you need to make only once or twice a year. You should, however, regularly check with a try square to see that the fence is exactly 90° from the tables. On my jointer, this is something that sometimes gets out of whack. 

Before you can joint an edge, you must first establish a reference plane on an adjacent surface of the board you’re about to joint. At least one side of the board being jointed must be flat. This can be done on your jointer if its cutterhead is wide enough. If not, you can flatten a reference plane on your board with hand planes and winding sticks. Or you can do what I often do with wide boards: rip them in half to be reassembled after both halves have been straightened and surfaced on my 6" jointer.

Unfortunately, you can’t straighten a board with your thickness planer because its tables are too short.  This tool simply makes one surface of the board smooth and parallel to the opposite surface, and if the reference surface rolls up and down like a piece of cooked bacon, the thickness planer will smooth the opposite surface while retaining the ripples.

While you can edge joint stock that has only one face flattened (the one you’re going to press against the fence), having a pair of straight, flat, parallel surfaces offers more options when feeding stock across the jointer. So I recommend flattening the opposite face on your thickness planer. It isn’t necessary at this time to take the board down to its finished thickness.

Once you’ve established at least one flat reference surface, you’re ready to begin edge jointing. Start by setting the depth of cut. If the edge is straight, fresh from the saw, you can begin with a fairly light cut, perhaps 1/32". If, however, the saw cut is an old one in which crook has developed during drying, you’ll save time if you start bigger, perhaps 1/16" or even — for a badly crooked board — 1/8". 

Typically, one edge of a board will be concave (when viewed from above) and the other, convex. Since it’s easier to straighten the concave edge, that’s where I usually begin. First take a couple of passes from the edge you’re going to straighten at each end of the board. This reduces the concavity. Sight the edge frequently to assess your progress. When the edge is nearly straight, it’s time to joint the entire length.

Begin by placing your feet comfortably to the left rear of the jointer’s infeed table. Place your left hand on the front top of the board to hold the leading end flat on the infeed table. Let the fingers of that hand press against the board so that the opposite face is pressed tightly against the fence. With moderate and consistent speed, move the bottom edge of the board along the infeed table and across the cutterhead (Fig. 1). 

As the front end of the board crosses the knives, exert a little more downward pressure with your left hand so that the freshly jointed edge is kept flat on the outfeed table. As you work your way along the length of the board, you should transfer more and more of the downward pressure from the back to the front (Fig. 2). At the very end of the stroke, concentrate on keeping the bottom edge of the board flat on the outfeed table. 

Check your work to see that the jointed edge extends across the full width and length of the edge. 

Your final pass should be a light one that you feed past the cutterhead slowly. This combination of light pass and slow feed will reduce — but not eliminate — the faint ripples on the jointed edge.

Check your joint with a straightedge. Then run a square along its length to check for a true 90° from the adjacent face.  

To give your work a final check, place one of the boards you’ve jointed in your vise (or on your bench between dogs) with its jointed edge up. Then place the other board atop that with its jointed edge down. With a straightedge, check to see that the faces of the two boards are in the same plane (Fig. 3). If they are, and if there are no gaps between the jointed edges, you’re ready to glue up your panel.

Some craftsmen — me included — often “spring” glue joints. We take an additional light pass from the middle 70-80% of the edge’s length. This means that when you sight an unglued sprung joint from the side, it will be tight on either end but have a faint crack of light in the middle. Springing the joint ensures that its ends will lock up tight once you’ve applied enough clamping pressure to close up the small gap in the middle.

Forming the joint by hand

Traditionally, butt joints were made with a jointing plane, a plane with a sole longer than 20". This length is necessary to prevent the plane from following any hills and valleys in the edge being jointed. 

If you’re working with short stock, a long jointing plane isn’t necessary. If, for example, the pieces you’re jointing are 8"-10" in length, a jack plane with a 12"-15" sole would be long enough. But if you’re working with longer stock, you should consider a longer plane. The Stanley company classified only those planes 22" in length and over as jointers. This included the #7 and #8 Baileys, the #607 and #608 Bedrocks, and the #30-#34 transitional planes.

The plane you use for jointing should have a reasonably flat sole. When I purchased my first wood jointer, I laid a straightedge along its length and noticed there was a bit of crown with the high point at the mouth. But since the amount of error was less than 1/16", I decided it didn’t matter. But several hours later, when I realized I simply could not force the plane to take a shaving from the full length of a board, I decided to pull the iron and straighten the sole. Working with my reliable Stanley #8, it took only a few minutes to produce a perfectly straight sole on my wood jointer, but that small effort produced a significant change in performance. I was able to take a full-length shaving on the very first pass. 

Unlike a smoothing plane, a plane used for jointing doesn’t require an extremely tight mouth. The mouths on some of my antique wooden jointers are almost 1/32" wide, and those planes function very nicely. By contrast, the jointer Tom Lie-Nielsen shipped me to try for this article — his magnificent #8 — arrived with a mouth that was only 1/128" wide (at least, that’s the best estimate I can get with my machinist’s rule).

Edge jointing is a skill that requires practice. That’s true if you’re working with a machine jointer, and it’s even more true if you’re working with a jointing plane. Before you attempt to edge joint material you actually intend to glue up, you should work out your stroke on some practice material.

To be instructive, that practice material should be moderately long — 20" or more, and it should be sawn to a reasonable straightness.

Clamp the stock you’re jointing into your vise or onto your bench top. Make sure the work is aligned to joint in the direction of the rising grain. If it’s not, your first stroke will reveal the error as you see the plane leaving behind torn-out areas. But remember that wood grain might not all run in the same direction on the same board. In this case, take lighter passes to reduce tearout. 

Otherwise, set your jointing plane to take a moderately thick shaving, thinner than a sheet of printer paper but not so thin you can read through it. You could get where you want to go by taking many transparently thin shavings, but it would take a long time.

Hand positions are subject to personal taste. I prefer to wrap three fingers around the tote — even a large one like the tote on the LN #8 that would accommodate all my fingers — and point my forefinger in the direction I’m planing. The pointing finger is not important to the mechanics of my stroke, but it is important psychologically, simply because it’s become a part of my edge-jointing routine. 

Forgive me if I sound a little “New-Agey” here, but I believe accurate edge jointing has a significant psychological component. Guiding your plane through an often-lengthy stroke with the plane held exactly 90° from the adjacent face of the board is more than a matter of simple mechanics. Think about hitting a curveball or shooting a jump shot. Jointing a perpendicular edge requires the same kind of mind-body connection. 

I wrap the thumb of my forward hand around the knob (Fig. 4) or rest it on the strike button of a wood plane (Fig. 5), with the fingertips of that forward hand trailing along a reference surface of the piece I’m jointing. I see little mechanical advantage to this hand posture, and I suspect other hand positions would work as well, but I “feel” that dragging my fingertips along the adjacent surface helps me to keep that precise 90° alignment. Before you begin planing, take a moment to study the body/hands/tool/work alignment in Fig. 6. Plant your feet squarely and in such a way that you can take a shaving from the whole length of the work without moving your feet.  If the practice material is long enough to require you to move along its length, set your feet so that you can take the necessary steps without sacrificing balance. This requires a certain amount of athleticism. It’s a dance that you do with the work, and you should practice the steps and the motion before you engage the work with the cutting edge of your tool. 

Place the plane so that the leading portion of the sole is resting on the top surface of the edge to be jointed. Apply a light pressure on the toe with your leading hand.

Then with your back hand — the power hand — move the plane forward so that the cutting edge engages the work. This will take some force if you’re working a tough domestic species like hard maple, but softwoods such as poplar cut like butter.

The object is to take slow, controlled strokes. Some novices take quick, rabbity strokes, the results of which are rarely good because they don’t allow for precise alignment of hands and tool and work. Ideally, the stroke should be one continuous push from one end of the board to the other, but if you have to choose between losing the plane/work alignment or stopping, choose stopping. Adjust your feet and your balance, then continue.

Once the entire plane is on the edge being jointed, you should have an approximately equal amount of light downward pressure on both the leading and the trailing hands.

But when the toe begins to approach the end of the work, transfer pressure to the trailing hand. By the time the toe of the plane leaves the end of the edge being jointed, all the downward pressure should be on the trailing hand. The forward hand will simply be catching the weight of the plane as it leaves the work.

Use a straightedge and a square to check your work (Fig. 7). You can also examine the shaving. If your plane is cutting full-length, full-width shavings (Fig. 8), you know you’re maintaining a good cutting edge/work surface interface. Continuous shavings that are a bit thick will often curl up in neat little rolls (Fig. 9). Thin shavings will be almost transparent. You can even take full-length, full-width shavings from difficult varieties like the hard curly maple in (Fig. 10). Make the final test in plane performance by standing one board atop the other as shown in Fig. 3.

The list of possible edge-jointing errors is long. You could — by using a too-short plane — create hills and valleys in the edge. You could — by failing to transfer the downward pressure properly from your leading to your trailing hand — create a crown on the edge.

But the mistake you will make most often is jointing an edge that’s something other than 90° from your reference surface. Never attempt to correct this error by cocking the plane one way or the other. Such a maneuver will interfere with the muscle memory you’re trying to build. Instead, when the angle is not right, you have two options.  First, you can re-rip the edge and start jointing again from scratch. Second, you can correct the error by re-jointing with the plane held precisely 90° from the reference surface. The second option is more demanding, but it can serve to reinforce the necessary mind-body connection.

Is edge jointing by hand worth the effort it requires? Absolutely.Yes, it’s easier to edge joint on a machine, but the sleek flatness of a well executed hand-planed joint is superior to the rippled machine-produced equivalent. Plus, a hand plane doesn’t make any noise. Plus, it doesn’t eject any dust into the air. And as anyone who has mastered a hand-tool technique will tell you, the skillful application of hand tools to wood is a profoundly joyous activity.

The Best of Both Worlds

Machine jointers are much better than jointing planes at quickly straightening a badly crooked edge. For beginners, they are also much better at establishing that 90° relationship between the edge and the reference surface. But they always leave a rippled edge, which I believe interferes with the quality of the glue joint.

In my shop, I often use the machine jointer for what it does best — quickly straightening and squaring crooked stock — and I then use the hand plane for what it does best: producing a silky smooth and perfectly flat surface.

This brings me to a recent discovery. 

Brian Buckner, a highly skilled amateur plane maker, added a wood fence to a transitional jointer. Transitional planes have wooden bodies and metal, Bailey-style adjustment mechanisms. In the eyes of the 19th-century minds who invented them, these hybrids combined the wood-to-wood interface many traditionalists prefer with the adjustment ease of a Bailey-style plane.The addition of a fence is a later idea, inspired perhaps by the add-on fence Stanley once offered for its metal jointing planes. 

Brian rabbeted his fence so the working surface would be moved far enough across the plane’s underside to meet the iron’s cutting edge. I opted for a two-piece construction, one that moved the working surface a little farther across the plane’s underside. This allowed me to get the ¾-4/4 stock I might be jointing closer to the middle of the plane’s sole, a move I thought would improve the plane’s balance in use.

I have to admit I was skeptical. I had never used a jointing plane with a fence, and I expected the whole thing would be awkward and cumbersome.

I couldn’t have been more wrong. Because I had chosen — following Brian’s example — to attach the fence to a relatively light transitional jointer, the extra weight simply wasn’t a problem. In fact, the jointer-with-a-fence probably weighs less than most unfenced jointing planes. Plus, unlike a thousand other (often harebrained) ideas I’ve tested in my shop, this worked perfectly from the start (Fig. 11).

When using a machine jointer, you tightly press the work against the machine’s fence. When using this jointer-with-a-fence, you do the opposite, but the effect is the same. In each case, you’re using a fence to establish a reliable reference surface.

I don’t know how often I will turn to this jointer-with-a-fence. My system of machine jointing then using a jointing plane is one with which I’m comfortable. But I do think if I was starting out, and struggling to get good results with a jointing plane, I might turn to this combination.

Kerry Pierce

Kerry Pierce is the author of a dozen woodworking books and more than 60 articles for woodworking magazines. His most recent book, “Authentic Shaker Furniture,” was the main selection of the Woodworker’s Book Club. 

0 Comments

Write Comment

Write Comment

You must be logged in to write a comment. Log In

Top of Page