
Fly Cutter Explained: From Basics to Advanced Techniques
A fly cutter is a rotary cutting tool that attaches to a milling machine spindle and rotates to remove material. The cutting bit extends from the tool body and cuts in an arc pattern with each rotation, creating a smooth, flat surface.
The tool creates flat surfaces because the cutting edge is set at a consistent height. Each pass removes a thin material layer, and the milling machine’s feed movement creates a flat surface. This process is sometimes called “fly cutting” because of the cutting edge’s sweeping motion.







