Attempting to precisely machine hardwoods presents a whole set of challenges not encountered when shaping metal. Unlike most metals, all woods have definite grain directions and variable densities that can significantly affect their cutting properties. The finished quality of edges and sidewalls can change dramatically, depending on the direction that the material is cut. Since the fabrication of any practical component requires that the material be machined from all directions, the burden is on the tool designer to develop bits that will cut uniformly over a wide range of hardness, abrasiveness, moisture content, and surface properties.
Problems encountered include top-edge splintering, poor sidewall definition, splitting, and imprecise dimensions of the finished part. However, with the right equipment, cutters, and procedures you can machine virtually any hardwood to produce smooth inlay pockets and components of remarkable accuracy and precision.
A thorough knowledge of the characteristics of the wood you are working is crucial to the selection of the correct cutting tools for and dialing in optimal machining parameters.
We have tested a variety of hardwoods and have determined initial values for the most important cutting parameters that should work with most CNC based routing / milling systems. The woods are separated into 3 categories based on relative hardness (Janka scale), the parameter that plays a dominant role in determining machining properties. These initial values may be extended as you gain more experience with a particular wood and refine the requirements of your application. If a wood is not listed, try selecting the closest fit from the list and test the cutting parameters on the material you are working with.
This list will be expanded