Free Chipload Chart


Vortex Tool Company, Inc. in Schofield, Wisconsin is offering a downloadable chart that can be used to figure out the proper feed and speed for CNC routers, when using variously sized bits (tools). Click on the small icon (just above where it says PDF) to download the chart. Chip load, according to CNC instructor Ted Bruning, describes “the amount of work being done each time a tooth or carbide insert passes through the material being cut, and this is determined by three factors. The first is the feed rate. The faster the tool is fed to the material, the bigger the bite. Next is the spindle speed. A slower rotation results in a larger bite, while a faster spindle speed results in a smaller bite. And the third factor is how many cutters (flutes) are on the bit. For each revolution of a single flute tool, one chip is produced. If the tool has two flutes, then two chips will be produced each time it rotates. With the same feed rate, depth setting, diameter and spindle speed, a two-flute bit will remove the same amount of material but will produce chips that are half as thick as those made by a single flute tool.” (Ted Bruning has written an article on CNC feed and speed rates in the August 2020 issue of Woodshop News.)