How Does a Jointer Work? | SawsHub

Home Articles Jointer Fundamentals. This article is from Issue 47 of Woodcraft Magazine. The jointer belongs to the trinity of stock-dressing machines that also includes the tablesaw and thickness planer.

Although its job is simple—straightening and flattening stock—the tool frustrates many woodworkers because jointing requires a certain finesse. However, when set up and used properly, a jointer will do its job precisely and efficiently in a way that no other machine can.

With a jointer, a workpiece fed across the infeed table is cut by knives that are set at top dead center to the height of the outfeed table, as shown in Figure 1. The outfeed table supports the cut surface as the remainder of the board is jointed.

To eliminate or minimize tear-out, orient the workpiece so the knives rotate in the same direction as the slope of the grain, as shown. It can also cut chamfers, rabbets, bevels, and tapers, but those are tricks for another time.

Although the jointer can how does jointer plane work out wood from both faces in turn, the result is almost certain to be a tapered board. Sight the edge of how does jointer plane work out board against a contrasting background for better visibility. This board has a slight crook.

How you orient a board depends on its warp Figure 2 and the slope of its grain. For stability when feeding, place the concave face or edge against the jointer tables. When face-jointing, this means you should orient the cup or bow downward. When edge-jointing, the crook should be at the bottom. That way, the board will ride on its high spots, providing better footing. Conversely, if you try to feed with the convex side downward, the board will rock, making control difficult.

Begin by sighting down the edge of a board Photo A. This will clearly reveal any bow or crook at how does jointer plane work out same time. If a board has an extreme crook, saw it away first, in the same way you would rip away a live edge, as shown in Photo B.

Cup is generally evident at a glance, but you can sight across the end of the board to be sure. Before jointing, rip away any live edge or extreme crook, guiding the board with a temporarily attached straightedge bearing against the rip fence.

After determining which edge or face gets fed downward, orient the board so the knives will rotate with the direction of the grain slope Figure 1 instead of against it, which can cause tear-out. If it reverses, just favor the direction that cuts mostly with the slope. Finally, set the jointer for an appropriate depth of cut. Begin a cut standing with feet splayed. Then move along with the board in sideways half-steps.

Successful jointing depends on the proper body stance, feed pressure, and feed speed. When feeding, begin by standing how does jointer plane work out your feet splayed for good footing Photo C. Lay the board fully on the infeed table just in front of the cutterhead guard, pressing the leading end down firmly.

Push the board forward while maintaining downward pressure at the leading end and forward pressure at the trailing end. As you move along with the board, waltz sideways by bringing your right foot against the left; then step widely sideways again.

When your belt buckle is about 10" rearward of the cutterhead, plant yourself there and complete the cut by moving the board forward with your hands, maintaining downward pressure over both the infeed and outfeed tables without overreaching.

The scalloped edge is the result of feeding a board much too fast, while the smooth edge indicates an appropriate feed rate. Avoid applying excessive downward pressure when face-jointing thin stock or edge-jointing narrow pieces that flex.

The idea of jointing is to gradually remove the high spots in order to bring the surface into a flat plane. Instead, press down just enough to keep the knives from slapping the piece upward. Proper feed speed depends on the density of the wood, the width of the piece, and the depth of cut.

Your best gauge of the proper feed rate is the cut itself Photo D. Moving too quickly creates a scalloped surface. Taking a couple practice passes and then inspecting the resulting surface should tell you what you need to know. Face-jointing is the first step in thicknessing stock. If you do that, by the time the entire bow is removed, the board may be too thin at its ends to suit your purposes.

Instead, first crosscut your project pieces a couple of inches oversized in length, as shown in Figure 3. Similarly, ripping cupped stock to rough width can help flatten stock before face-jointing. Next, orient each piece as discussed earlier—with the concave face down how does jointer plane work out the grain sloping in the direction of the cut. If necessary to read the edge grain, take a quick pass or two off the edge.

If cup and bow are on opposite faces, lay each how does jointer plane work out of the piece on the table in turn, rock it to see which orientation is how does jointer plane work out stable, and go with that orientation.

When setting your depth of cut, err on the shallow side for starters. Then take a test cut. If desirable, increase the depth of cut for efficiency.

Repeat as necessary until the face is flat. A twisted board can be a problem because it rocks no matter which face is down. The trick is to balance it as best you can for the first pass or two, after which the board will gain footing.

Handling long boards also requires some nuance, as shown in the photos at left. First of all, before beginning the cut, make sure your heeled pushblock is within reach.

I set mine on the jointer behind the fence. With your left hand, reach as far forward as you comfortably can to press the leading end of the board against the table. Feed the board forward while providing enough upward support at the trailing end to maintain contact with the table. When the board is fully at rest on the tables, grab your pushblock and complete the cut. Orient your workpieces ahead of time with any crook downward and with the grain slope favoring the cut, as discussed earlier.

The trick to getting a square edge is to keep the previously jointed face how does jointer plane work out the board in intimate contact with the fence throughout the cut.

At the same time, you need to protect your hands from that potentially vicious cutterhead. Try this approach, which ensures stable feeding even on a small jointer with a low fence. To prevent blowout at the end of the how does jointer plane work out when jointing end grain, clamp or glue a backup block to the trailing end of the piece. The key here is to splay the fingers of your left hand so that they apply pressure at both the top and bottom edges of the fence, while pressing downward with your thumb how does jointer plane work out the same time.

As you approach the guard, raise your lower fingers safely above it while maintaining pressure against the fence. Once past the guard, drop your lower fingers again. The only issue is that the unsupported fibers at the trailing end of the cut tend to break away. To prevent that, just back up the workpiece.

One approach for shorter pieces is to clamp on a support block, as shown in Photo E. For larger pieces, where a clamp would be unwieldy, you can temporarily glue the block in place. Once past the guard, drop your lower fingers back down to the bottom edge of the fence, and plant your hand there to complete the cut.

Near the end of the cut, increase downward pressure on the end of the board to prevent its leading end from dropping. Part of the problem is that a long board tends to arc over the tables. Just as a longer hand plane shoots an edge better, a longer jointer is better suited to handling long boards. With a bit of practice, you can learn to successfully maneuver a long board on the jointer.

Try this approach, as shown in the photos above. Turn the machine on. Then, supporting the board on edge at its center, lay its leading end fully onto the infeed table.

Rock it up and down a bit, observing and feeling when it contacts the front and rear end of the infeed table. Level it out as best you can, and hold it at that level as you maneuver it sideways against how does jointer plane work out fence. Peer over the back of the board to monitor the contact against the fence.

Now begin feeding forward while continuing to monitor the contact between the board and the fence. When the full weight of the board is on the tables, move closer to the center of the jointer for better control. As you approach the end of the cut, increase your pressure on the trailing end of the board to prevent the leading end from dropping.

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Each machine does a completely different surfacing operation. A jointer flattens a face or straightens and squares an edge, and a planer thicknesses wood. Whether you need one, the other, or both can easily be answered by knowing how they work, what they do, and how much wood surface preparation you pay your lumberyard to do for you. A jointer is a very important tool in a woodworking shop. Its job is to set the foundation for all future work you will be doing with a board. Being able to. How to Flatten Boards With Just a Planer: In woodworking, there are often many routes to reach the same destination. This is one way to flatten* large boards using primarily an electric thickness planer (without the help of a jointer). In order to flatten a warped, twisted, or cupped board,.

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