Cut Accurate and Clean Rabbets

Single Setup with Stack Dado Set

The height of the dado stack determines the depth of the finished rabbet. This is 1⁄2″.

The distance from the top of the left tooth to the fence determines the width. This is 3⁄4″.

One nice thing about making a rabbet on the router table is that you can (within reason) do it with a single tool setup. You can control the width and depth of the joint simultaneously, tweaking the height of the bit and the fence (which exposes the tooling) until the joint is just right.

To do this same thing on the table saw you need two things: a stack dado set and a long length of plywood you can clamp over the working surface of your rip fence. The wood allows you to “bury” the dado stack in the fence so it will work like the fence on a router table.

This accessory fence should be straight, at least 1⁄2″ thick and as long as the table saw’s rip fence. Plywood is a logical choice of material because it doesn’t tend to warp.

The first time you use this accessory fence, lower the dado stack below the surface of your saw’s table. Next, clamp the accessory fence to your rip fence and then position it so that about 1⁄8″ of it covers the blades below. Then, turn on the saw and slowly raise the blades into the fence until you’ve cut away about 1⁄4″.

The same rules for ripping and crosscutting apply to rabbeting. For ripping cuts with the grain, use the fence to guide your cut.

Another necessity to ensure an accurate and safe cut is to use a featherboard that presses the work against the table. There are lots of commercial featherboards available, or you can certainly make your own. As you can see from the photo at right, I also added an aluminum T-track (in a rabbet, no less) that allows me to quickly adjust the featherboard’s position. That’s mighty handy when dealing with project parts that are of different thicknesses.

Now you’re ready to make rabbets. Using a 6″ rule (see “Almost-perfect 6″ Rulers” on page 25), set the height of the dado stack to equal the depth of the rabbet you want to cut. (Tip: Spend some time finding the point where your blade’s teeth are at their highest. When you’ve found that sweet spot, mark it on your table saw’s throat insert; I use a scratch awl. In the future, you can just set your ruler on that mark and measure. You’ll be amazed how much time this saves you.)

Next, set the saw’s rip fence to expose enough of the dado stack to make the width of your rabbet. With practice, you can almost always hit that measurement exactly on the first try. Lock the height of the arbor on your saw. This is especially important if you own a benchtop or contractor saw. In smaller saws, the mere force of the cut can cause the arbor to creep downward.  If it creeps just a bit, that’s the worst. You might not find out about the problem until assembly.

Turn on the saw. Follow the same rules you do when ripping or crosscutting. If it’s a ripping operation, you can simply press the work against the fence and push it through the blades. The same goes for work that is square or nearly square (such as the side of a base cabinet). After your first pass, check the depth of cut with a rule or dial calipers all along the joint to make sure your featherboard is pressing down hard enough to prevent the work from rising during the cut. If the joint is inconsistent, increase the tension on your featherboard or push the work a little harder against the saw’s table.

Sometimes taking a second pass will fix your problem. While that’s not ideal, it’s worth a try if you are stuck and out of options.

Remember: Any cup or warp in your workpiece can ruin the accuracy. And plywood is not always as flat as we would like it to be. If you’re having trouble getting a consistent joint, check the work to see if it’s cupped or warped.

When crosscutting rabbets across the grain, you have two choices: Use a miter gauge if the stock is narrow or, for pieces wider than 8″, use the rip fence and a backing block behind the work. A backing block will stabilize the part during the cut. You don’t want to use a backing block to cut narrow pieces because the work could slide right into the cavity in the accessory fence. And that’s when you’ll find out how tough the anti-kickback fingers on your featherboard are.

For crosscutting across the grain, use the miter gauge for narrow pieces or use the rip fence and a backing block (to prevent tear-out) for larger pieces.

To rabbet the ends of large case sides you’ll definitely have to forego the miter gauge. Using a backing block here will reduce the chance that you’ll tear out the grain when your work exits the dado stack. As with ripping operations, making a second pass sometimes helps ensure your cuts are more consistent.

As a bonus, you can cut rabbets this way with an overarm guard in place. Because the guard obscures the blades, we’ve removed it for these photos, but it is an important part of the setup.

As much as I like this technique, it isn’t perfect. When crosscutting against the grain, the cut is a bit rougher than if you used a router, though I can’t report any gluing problems with the joints cut using a dado stack. Cuts with the grain, on the other hand, are quite smooth.

Another cause for concern is your saw’s motor. Benchtop saws don’t really have the guts to make casework rabbets (plus many don’t have a mechanism to lock the height of the arbor – a major problem). In fact, the fences of benchtop saws usually are too inaccurate to cut the joint using the two-step process mentioned earlier. If you own a benchtop saw, you should consider cutting your joints on a router table.

However, larger saws, such as contractor- and cabinet-style saws, usually breeze through these joints in one easy pass over the dado stack.

All things considered, I found that maneuvering workpieces on the larger table of the table saw is easier than cutting the same size pieces on the router table. Plus, the power of the table saw made the cuts easy to accomplish in one pass without taxing the machine or the tooling.

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