Milling standards
National and international standards are used to standardize the definitions, environmental requirements, and test methods used for milling. Selection of the standard to be used is an agreement between the supplier and the user and has some significance in the design of the mill. In the United States, ASME has developed the standards B5.45-1972 Milling Machines and B94.19-1997 Milling Cutters and End Mills.
General tolerances include: +/1.005" for local tolerances across most geometries, +/-.010" for plastics with variation depending on the size of the part, 0.030" minimum wall thickness for metals, and 0.060" minimum wall thickness for plastics.
