5 Ways to Make Precision Rabbet Cuts
Although simple in appearance, there's more to the rabbet cut than first meets the eye. To make the best use of rabbets, you need to know the various ways to cut them, when to use each method, and how to make the cuts effectively.
A rabbet is simply a rectangular recess along the edge or end of a workpiece. Although most often found as a joint in casework), a rabbet also can pop up as a design feature in a molding, as a recess for holding artwork in a picture frame, along the edges of a cabinet door to help recess it partway into its face frame, or as a half-lap or shiplap joint.
In the WOOD® magazine shop we cut rabbets with a tablesaw (set up with a dado set or combination blade), router (handheld or table-mounted), or jointer. The choice depends on the type and quantity of workpieces, and the desired quality of the rabbet cut. Here's what you need to know about each method.
1. Tablesaw with a dado set. We use this setup often because it yields clean rabbets in one pass typically-two passes for wide rabbets. For good results, you need a high-quality dado set. Since it takes a little time to install the dado blades, we use this method only if we have several workpieces to cut.
To do this successfully, first attach a 3⁄4 " wooden face to your tablesaw fence. By doing this you can cut into the wooden face and fine-tune the width of the rabbet with quick fence adjustments.
2. Tablesaw with standard blade. If we're rabbeting just a piece or two, we'll leave our combination blade in the tablesaw and make the cut in two passes. The key: You need to precisely set the fence, and the height of the blade, for both cuts so one doesn't cut beyond the other.
First, cut the rabbet to its correct depth with the workpiece facedown on the tabletop. Then, stand the piece on edge to cut the rabbet to width.
If you don't own a good dado set, or have a low-powered saw, this option may prove better than No. 1 for all of your work. But, it can be tricky if you need to rabbet the end of a narrow workpiece. In that case, you will need to clamp the workpiece to a fixture that holds it steady and upright as you guide it along the fence.
3. Handheld router with rabbeting bit. Unlike saw blades and dado sets, router bits do not leave tiny scoring marks. So, use a router bit if the surface or ends of the rabbets will be visible in your finished project.
Router bits are your only option if you need to rabbet an opening inside a surface rather than along an outside edge or end. Examples include a router-table opening for receiving a router plate, or the inside of an assembled doorframe for accepting a piece of glass.
With a handheld router you typically use a rabbeting bit with a pilot bearing as shown above. You can change the width of the cut simply by changing bearings. And, with this setup you can even cut rabbets along curved edges.
4. Router table with a straight bit. Although you can't easily rabbet large pieces on a router table, this method has some distinct advantages over a handheld router. First, a router table has a fence that ensures a perfectly straight rabbet (a bearing-piloted bit will follow any irregularities in the workpiece edge). And, although a piloted rabbeting bit will help you cut a rabbet up to 1⁄2 " wide and 1⁄2 " deep, you can put a large straight bit in a router table and cut rabbets up to 1X1".
5. Jointer. We admit we rarely use a jointer to cut rabbets, but if you must cut a perfectly smooth rabbet over 1" wide, and along a straight, outside edge, look to a jointer. You can cut a rabbet as wide as the length of your jointer's cutterhead. The maximum cutting depth of your jointer will limit the depth of the rabbet, typically to 1⁄2 ".
To do this, you need to make an initial cut with your tablesaw. First, set the blade height to match the depth of the rabbet. Adjust the fence-to-outside-of-blade distance to match the rabbet width. As shown, this cut will prevent the end of the jointer's knives from hammering the workpiece. Remove no more than 1⁄8 " with each jointer pass.