Skill Builder: CNC Joinery

Week 5 Skill Builder:

This week, in preparation for the CNC Project I am testing out a couple of wood joints I would like to use. I want to make a simple, low to the ground offering table. For the legs I will be testing out a cross lap joint and for a decorative archway that goes over the top I will be testing out a through groove.

Supply List:

  • Wood

  • Digital Calipers

  • 1/4” Straight End Mill

  • Safety glasses and ear plugs

  • USB

  • VectorWorks

  • MasterCAM

  • CNC Router

Process:

After sketching out a simple design I researched CNC joints with it in mind, trying to find a joint that would best suit my design and fit my aesthetic preferences. I settled on using a cross lap and through groove. I then moved to Vectorworks creating the basic shapes that I would cut out of the scrap wood and then adding additional geometry that would inform my tool paths. Most of these were simple rectangles that extended beyond my actual shapes to ensure that the pockets would be fully milled out.

After completing this I took my files to MasterCAM and created the toolpaths. This was pretty straight forward although I realize I would have benefitted from writing the dimensions down. Since the two pieces of wood I was joining were going to be perpendicular to one another, but sit on the same plane in the file I had a hard time keeping straight how deep I should make my pockets. I had used the text tool in Vectorworks to jot down numbers on the actual file but this didn’t indicate where those numbers should be applied. This did lead to a mistake on one of the joints.

Other than that this process was very smooth and I am exploring adding additional joints to this project.

Next Steps:

As mentioned, I messed up my numbers for depth and thickness on the second joint so it is a little too wide and a little too shallow. I’m going to go back into MasterCam and recut this just to confirm the fit of this joint.

I may also experiment with a third wood joint (halving with elliptical tenon) so the decorative arch is made of a few interlocking pieces, rather than a single bar. I think having the arch be multiple parts would serve the design by making the table easier to breakdown and transport in smaller pieces that you don’t have to worry about snapping.

Sources:

[1] http://mkmra2.blogspot.com/2014/08/cnc-cut-wood-joinery.html

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CNC Project

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Skill Builder: MasterCam and CNC Routing