How to make a box joint jig to cut finger joints

Make a finger joint router table jig

Sometimes (most times) we want a way to make decent finger joints fast. And because these wooden joints are also very hard, we often think about using them to make wooden boxes or other woodworking projects. For example to keep our tools. And those are lots of cuts. So, why not making a finger joint jig.

If you ever tried to make a finger joint by hand, to make a wooden box, a small trunk or something similar, you already know it can be very difficult to make the fingers in one board fit perfectly with the sockets in the other board.

So, unless you are very skilled or a professional woodworker, making a box joint by hand can be frustrating. Sometimes I even got angry. I don’t say don’t try it, because we only will learn woodworking trying to make things ourselves.

Dovetail joints look nicer, and we could use a similar router table jig to cut the tails, but we need a different technique to cut the pins. Watch it in this video.

How to make finger joints or box joints

Before we decide to make our first piece of furniture, we usually make, first, some kind of box. Or we make some small trunk. It is a good way to learn and improve our woodworking skills before we decide to make bigger projects. So, we realize we must decide witch wooden joints we want to use. And we begin to pay attention to those finger joints that fit so perfectly. And we think about how to make a finger joint so it fits so nicely. The solution is a simple finger joint jig for router table that will make perfect box joints, fast, every time.

Making that box joints jig is a good reason to have a router table. But, well, it can also happen that you prefer a more rustic look, and you don’t mind if they don’t fit so perfectly. Or you may think a butt joint, with some glue and nails, looks better than this box joint with that mechanised look. Sometimes I will agree with you.

Finger joint jig for router table

A finger joint jig, to make box joints, is mainly a vertical piece of board with a small strip protruding the front in the base. That small strip has exactly the same width as the diameter of the router bit. And the distance between the router bit and that strip is also the same as the diameter of the router bit. We only need to make a simple sled so we can move it against the router bit. Or I can screw it to may sliding router table fence. That way I can use the vacuum cleaner system in the fence.

We just have to route a socket. Then we fit that socket in the small strip in the jig, and we route the next socket. And we repeat until we have routed all the sockets and fingers. That way all the fingers and all the sockets are exactly the same width, so they will fit making a perfect box joint. Well, a perfect box joint if the small strip is exactly as wide as the router bit diameter, and if we where patient to put the small strip, in this box jig, at the perfect distance from the router bit. I show how I did it in the woodworking video in this post.

Sled for the box joint jig

You can see a picture with the plans of the sled I made to use this finger joint jig. But actually it is something you must adapt to your router table. In the next woodworking video you can watch how I made the groove I have in my router table top to guide the sled. In case you don`t have that groove you can try to clamp two parallel strips on the table top so you can guide the sled in between those strips. But I never tried it, so I don`t know if that will work.

You can also watch how to centre the fingers and the sockets in the board so we don’t get a very thin finger in one end of the boards.

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