Some woodworkers just don’t believe in using CNC routers. They believe that someone who cuts and shapes parts with a CNC router is not a craftsman, and has little or no connection with the materials he or she uses. As someone who began his woodworking career with a strong interest in hand tools, I can understand this point of view. However, my time in the woodworking industry has taught me that proficiency with CNC routers requires more creativity and skill than most people probably realize.
No matter what tool you use to cut or shape a piece of wood, you need to know how the material is going to respond. When you’re cutting end grain, you’re going to tear out the back edge of it whether you use a handheld router, hand plane or a CNC. You need to clamp a block behind your board, chamfer the back edge or take some other action to prevent this tear out.
CNC routers cut solid wood just like portable routers and hand planes. They need to take shallow cuts and multiple passes. Setting a machine’s feed rate too low will result in burns, and setting it slightly too high will give you chatter. When a cut is too deep, a CNC router bit can break. Bit selection is also important, and you need to be able to choose from options like single-flute, straight flute, spiral flute, up-cut, down-cut and compression.
Work holding on a CNC can be a real challenge. Most commercial machines use vacuum systems to keep work pieces in place, with somewhat inconsistent results. If a part is too small, the vacuum won’t hold it. Operators need to know how to build jigs for these situations and how to accommodate them in CNC programs. Hobby machines usually rely on clamps or fasteners for work holding, and knowing how to arrange them, as well as how to program a machine to avoid routing into them requires skill.
Programming a CNC machine is an ability that takes time to master. You can learn the basic G Code commands that control a machine very quickly and use them to create simple parts. However, to really exploit a CNC’s capabilities, you’ll need to learn some kind of CAM software. Once you do, you can cut intricate 3D shapes and ornate carvings.
If you’re interested in learning to use CNC routers for your woodworking projects but are a little intimidated after reading the above, don’t be. Learning to work with CNCs is just like learning to work with hand tools; once you know your material and a few basic skills, you’ll be able to complete some simple projects. With practice, you’ll be able to do more advanced work. The real fun of CNC is in the learning process: exploring the code that drives the machine, using the software and figuring out how to hold difficult work pieces. I can tell you from experience that this process can be one of the most exciting and rewarding parts of your woodworking.
You can build your own CNC router for woodworking. Take Nick’s Popular Woodworking University course, Build a CNC Router. You’ll get a parts list, step by step instructions, a SketchUp model and dimensioned drawings.