Hi, this is Wayne again with a topic “Skillbuilder: Design for CNC Joinery”.
Cnc routers can make short work of just about any woodworking task, especially complex joinery. There’S just one problem: yeah, that’s just trying to fit a square peg to around it hole. You see the problem comes from how a router cuts wood. It uses a round bit, which means it can only make inside corners as sharp as the radius of the bit, but the outside corners can be as sharp as you like sure. You can clean up these corners with a chisel or a square file, but that’s a whole lot of work and that’s really defeating the point of having a CNC in the first place. Fortunately, there’s a few different types of CNC, specific Phillips that knock out the rounded corner, so your parts will mate together perfectly. Each of them has their own pros and cons, mostly in their aesthetic. So you can mostly make your decision based on what you think will look best for your project for all of these fellas. It’S generally a good idea to make your designs a little bit larger than the radius of your bed generally, ten percent larger. For each of these demonstrations, I’m using a quarter inch bit so I’ll, be using a radius of 0.275 inches. The wood I’m joining is some half-inch plywood, but these will work with any thickness of wood. The first is the dog bone. Filling this Philip places the radius of the circle in the corner, so the two faces can meet each other. It looks the simplest but mathematically. It’S the hardest to draw from the corner draw a 45 degree line inward from the corner. That is the same length as the radius of your circle. From the end of that line, draw your circle from the center and place its radius on the corner, do the same in the opposite corner and then clean up all of your access geometry. This phillyd is the most efficient because it preserves most of the wood, but it might not leave the most aesthetically pleasing joint for face joints. You can fill in the gaps with a little bit of wood filler, if you like. The next Filat is the t-bone filling. No, not that kind of t-bone, though, when you see it, it’s easy to see how it gets its name.
You can design this one by starting with your basic rectangular joint from each of the inside corners. Draw two points: circle, along the edge of the joint clean up your excess lines when making through connections like this t-bones can be ideal because you get a solid mating surface between the two intersection pieces, you can also get plenty of gluing area on interface joints like This one, the last fill that we’ll be talking about today, has kind of a funny name: the sniglet snig. Let’S look a lot like t-bones, but they allow the router bit to flow much more smoothly through the cut preserving momentum which can lead to a much cleaner result. They also cut away the most material from the joint, but they also have a really pleasing.
Look and again, that’s pretty subjective. Here’S how you make it again. You start with your corner, draw the radius of your circle so that it’s tangent to the outside of the corner then draw another circle right alongside it. Draw a line extending from your corner to a tangent of the first circle, trim away your excess lines and then do the same. For the other side. These Philips produce nice swooping lines away from your joins that almost look like the sounding holes on a violin.
Just keep in mind this Philip produces the least amount of gluing surface. This is just three different ways you can get inside corners of CNC cuts to join up, but the numbers of ways you can use them are pretty limitless. Of course, CNC joinery isn’t as elegant as fine woodworking, but you can easily use these joints to build up the internal structure and then cover it with a veneer or you can embrace the look. All of these joints come from the book. Designing for CNC buy and Filson Gehry Rohrabacher and Annika’s aeneas france check out the link below to purchase it. It’S filled with loads of designs for CNC and ideas for really complex joinery, thanks for watching. If you enjoyed this video or learn something from it, be sure to give it a thumbs up, and if you want to see more videos like this be sure to hit subscribe, we’ll see you next time. .
