Compression spirals are designed to produce a very smooth finish and significantly reduce sanding time. The alternating upcut and downcut flutes work together to prevent splintering and fraying on both faces of the workpiece. These 1+1 compression bits feature one upcut flute and one downcut flute and are compatible with any CNC machine. They are a necessity for most woodworking shops cutting laminated or veneered panels, and the most popular sizes are 1/2" and 3/8".