minimill

A minimill, or mini mill, is a compact milling machine designed for benchtop or small-floor installations. It provides vertical milling capability for light to moderate metalworking and is commonly used in hobbyist shops, schools, and small fabrication environments to fabricate small parts, fixtures, and prototypes.

Construction and capabilities: Most minimills have a rigid metal frame, a vertically oriented spindle, and a three-axis table. They can be operated manually with handwheels or controlled by computer numeric control (CNC) through retrofit kits or built-in CNC systems. Travel is modest, with several inches of movement in the X and Y directions and a similar range in Z on typical benchtop models. Spindle speeds vary widely by model, generally spanning from several thousand to tens of thousands of rpm. Toolholding is usually via a collet or small chuck, capable of accepting end mills, drills, and small boring tools. Power is typically sourced from standard workshop electricity.

Operation and capabilities: Minimills excel at light milling, drilling, pocketing, slotting, and contouring on soft metals such as aluminum or brass, as well as certain plastics. They are not designed for heavy metal removal or large, rigid workpieces. Workholding, cutting conditions, and lubrication are important to achieving quality results. Many units marketed to hobbyists are CNC-ready or compatible with common CAM software.

History and market: The minimill category expanded in the late 20th century as affordable, compact milling options became available for education, prototyping, and small-scale production. Today it includes manual benchtop models and CNC-capable units from multiple manufacturers.

Safety and maintenance: Use appropriate guards and eye protection, manage chips and coolant where applicable, and perform regular lubrication and alignment checks to maintain accuracy and longevity.