Dogbone filleting for joinery on CNC

Yesterday I made this little shelf to hold my spring seedlings. It has mortise-and-tenon style joints so I can take it apart and rearrange the heights. I wasn’t sure how I was going to cut them out because a round end mill can’t cut 90º inner corners, and they wouldn’t fit together snugly with a radius in the corners.

Most CNC operators probably already know about it, but VCarve has a tool (they call it a Gadget) that will look over your vectors and find any angles that can’t accommodate the tool diameter. It adds a little path to overshoot the corners, turning a 90º angle into a T-shape.

I installed it on the Swift CNC’s computer so others can use it. Vectric’s documentation for using it is pretty straightforward; you can find it under the Gadgets menu.

It’s not fine joinery to be sure, but for a utility project like this I was super pleased. Hope it helps somebody else!


If this is what you do for seedlings, would really like to see what you do for serious furniture. Great design! I would not mind using it as a book case or a shelf in a living room. Seedlings don’t deserve that kind of structures lol!

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