Creating Rabbets on a Jointer

There are two questions I often hear about the jointer, and the answers to those questions are related to the same thing. The questions are, why does the scale on a jointer go to numbers as big as 1/4, 3/8, or 1/2 inch? The other question is what's the deal with this arm that projects past the in-feed table? The answer to both of those questions is related to rabbeting on the jointer. This is a great thing to know about if your jointer's capable of doing it, once you know how to set it up, you're going to use it a lot. So, here's the way it works. What I can do on a jointer is slide the fence way over to the extreme left. Now, let's get a number out here. Let's say I want to make a rabbet that's 3/8 by 3/8, common for the back of a picture frame, say. What I can do is measure here, from the edge of the fence to the edge of the knife, set that 3/8 of an inch. The fence is going to stay right where it is. The in-feed table is going to be made progressively lower as we do each cut. So, of course, should do these setups with the jointer unplugged. I can plug my machine in, go ahead and do the first pass, then we'll walk through the rest of the rabbeting procedure. So, what's happened here, is that with that very light first pass I've cut a little L-shaped rabbet, just in part of the board. Now, typically on a jointer, what I would do is, if I were just jointing an edge, I would set the bed, I would set the scale, and I would just keep making passes at maybe a 1/32 or a 1/16 of an inch. If I make another pass now in rabbeting, nothing would happen, I wouldn't take any wood off. So, now what I need to do is increase my depth of cut, by dialing my pointer down, make another pass. When you're rabbeting on the jointer, each time you make a cut, you have to increase the depth of cut, until you get to your final setting. So, if we want 3/8 by 3/8, I'm going to have to keep going, until my pointer down here shows 3/8. I'm going to go to a 1/4 now, then we'll do one more pass to hit that final 3/8. So as simple as that, that's the completed rabbet, very nicely cut, by the jointer. On this particular machine I could go all the way down to a 1/2 inch depth of cut. Now, on some machines, you want to watch out, on the back of the in-feed table, there's a spring-loaded plunger, and what it does is when you dial down to a certain point, a lot of times it's at a 1/4 or 3/8 of an inch, that plunger engages and stops you from going any further. So, it's basically a safety device to help stop you from over cutting on a piece. If you're going to continue past that point, you need to reach around, release the spring-loaded plunger, in order to continue, in order to make deeper cuts beyond that. So, it's a very easy setup to do, like I said, great way to make very clean, easy to do rabbets on the back of a board.