Downcut Spiral Bits are best used for thinner materials, or when a high-quality cut finish is required on the top surface of cut parts. The trade-off for this cleaner cut is that waste material (sawdust, etc) is pushed down into the machine bed rather than being lifted out, the way it is with an upcut spiral. Downward spiral tools often require reduced cutting speeds because the dust is pushed back into the material. The term “downcut” refers to the orientation of the spirals flutes (the grooves) relative to the bit's rotation direction. It can be thought of as an airplane propeller spinning the opposite way, pushing air forwards. Maker Made CNCs solid carbide router bits are designed to handle a variety of materials with ease. The down cut bit is designed to push chips downward leaving a perfect top surface. The downcut router bit is perfect for the Maslow CNC and other CNC machines.