Finger Joints on the CNC

Disclaimer: Noob

Finger Joints. I know how they’re done with a table saw but on the CNC- is there a way to do finger joints on 3/4" ply? I’m super new to using the CNC but it seems to me that because the cutter is round, that cutting tight 90 angles doesn’t really work. Is there something I’m missing?

The simple answer is that you need to mount your boards vertically. Pulling this off requires 1) a vertical clamping fixture and 2) a CNC that allows you to mill beyond the boundary of the bed. Here are a few resources to give you the idea:

There’s much to learn about this but the results can be really beautiful.
Few software focus on this capability but JointCAM is worth checking out.
That said, the fancy stuff in the video above was all done in VCarve Pro.

dogbone fillet is what I believe your looking for

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There is a box joint jig for the table saw, but it’s a gear driven mechanism that is fairly complicated. You can also do box joints on the router with the Incra jig that is mounted there, but you might want to purchase the Incra book that they sell on their site.

Or you can do the cool complicated stuff on the CNC…

What is ya’lls preferred joinery for making boxes using the CNC. Right now, I’m making a toy box for my kids and I wish I would have just used rabbits. But I’m wondering for the future what types of joints people like using. I imagine there’s some cool stuff you can do.

Here are some good videos explaining the basics. - this one uses a different program but the steps can all be replicated on vcarve. - fast forward to the last project in the video. He does mount the wood vertically so that the bit can create nice square joints. You’d need to create a jig on the far end of our cnc to hold your wood vertically.

There is also a dovetail box gadget you can download from vcarve that will do a lot of the heavy lifting for you. I think you just have to go through and add some fillets to the file. You can select dovetail or box joints.