Face Jointing and Parallel Edges
George VondriskaOne of the most common questions we get at WWGOA is about using the jointer and how to get parallel faces and edges from the jointing process. To answer this question, it’s important to understand what jointers do and don’t do. Once you get this, you’ll be better able to get what you want from your jointer.
Jointers Excel At…
Here’s what jointers do really, really well. They make surfaces smooth and straight. And, if you’re working on an edge, they’ll make the edge square. They do the work that used to be done by a hand plane.
Jointers Don’t Excel At…
Simply jointing one edge, flipping the board, and jointing the other doesn’t mean you’ll get parallel edges. Same goes for faces. The opposing surfaces will be smooth and straight, but not necessarily parallel.
How Do You Get Parallel?
To get two parallel surfaces you need to roll another tool into the equation. For edges you’ll joint one edge and then go to the table saw to rip the opposite edge. For faces, joint one face and then use a planer to make the opposing face parallel. Jointing opposite faces simply doesn’t work to make them parallel.
Are Jointers a Must-Have Tool?
Where do jointers sit on the hierarchy of tools you should put in your shop? It depends. If you’re good with a hand plane you can edge joint and face joint with that. If you have a router table you can edge joint with a router table (but not face joint). You can also use an electric hand plane to do some of the work. But it’s hard to beat the consistency that comes from a jointer.
Get the Most From Your Machine
Check out more jointer videos, and tips for mastering your jointer, to make sure you’re optimizing your machine.
I'm gonna address a question that myself and the other people who answer questions on goa.com get all the time. Here's the question we got, "I face jointed a board and I flipped it over and I faced jointed the other face but they're not parallel to each other. What's the deal?" And in that case, you're asking something of a jointer that it can't provide. So here's what I'm gonna do. I'm gonna face joint one face, and then we're gonna move forward from there and walk through why this doesn't work like a planer.
All right. What do we got? A few more passes, that will be smooth and flat. Now, when this side is smooth and flat and I flip it over and start doing the same thing to the other side, what we don't know at this stage of the game is how parallel those two faces were from the sawmill. And they're probably reasonably close, but not perfect.
But the problem we have here is that there's nothing for this face when I flip it to register against, to guarantee, that this face is gonna come out parallel to it. And that's not only parallel this way but also parallel this way. So it's possible that we have this face, smooth and flat. Then we flip which I'm about to do and do this. And we get this face, smooth and flat.
But the dynamic here is such that those two faces, there's a good chance they're not gonna be parallel to each other when we're done. Again, because we don't have a reference to run this against. The difference here is that when we take this space to a planer and we put that flat face down and start taking material off the top, because of the way planers work, this is referenced against the bed of the planer and the cutterhead is taking off all the high points, taking off all the high points, leaving behind uniform thickness and parallel faces. So, to basically prove my point, I'm gonna finish this side then I'm gonna flip, get this side smooth and flat, and then we're gonna take digital calipers and see what we get. Yeah right.
Well, we don't even need the calipers, do we? When we look at this board, that face is smooth and flat. It's got a little more to go there but it's primarily smooth and flat. That face, primarily smooth and flat. But look at what happened here.
We've got a lovely wedge. How about in this direction? Same thing going here. I think we are, let me look, a little bit fatter here than we are here. So it just can't, the dynamic of a jointer is such that you can't get two faces smooth, flat, and parallel using a jointer.
We really need that marriage between one flat face, take it to the planer, get the other face flat and parallel to it. So that is my lesson for the day on face jointing. And it's great to face joint but it's only got so many capabilities and you need to understand the limitations in order to make sure your materials coming out of it accurately.
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