Drainboard bits are used to rout a series of shallow, evenly spaced grooves into flat countertop surfaces including solid surface, marble, granite, and engineered stone. These grooves channel water away from the surface and direct it toward the sink, improving both the functionality and visual appeal of kitchen and bathroom countertops. The bit geometry typically produces grooves with flat bottoms and rounded edges for smooth drainage and a clean, finished appearance. These bits are a practical tool for any fabricator producing drainboard countertops or adding drainage detailing to existing surfaces.