Consider Part Tolerances—When Necessary

Making parts more accurate than is absolutely necessary is another common mistake. When tolerances are tighter than needed, the machinist may be forced to modify the part program, use a special cutter, or even perform a secondary operation to meet that tolerance. Whenever possible, it’s better to stick with the default “block tolerances” called out on any part drawing, or ask your machining partner for advice as to what’s reasonable.