Establish the reference faces
Custom CNC milling parts often rely on planar faces, pockets, slots, and hole patterns. Identify the datum faces and explain how the component locates in its assembly. Provide the drawing and model, part number, material, quantity, and current revision.
Describe pockets, slots, and hole relationships
Show feature depth, wall relationships, hole position, thread details, and any open or closed pockets that matter to function. Mark the dimensions and datums that govern fit. Include mating-part or assembly information where it clarifies the required feature relationships.
Specify material and surface requirements
Use the approved material callout and identify any required coating, anodizing, or other finish. State which surfaces are affected and whether final dimensions apply before or after the secondary operation.
Define inspection and edge conditions
State how critical positions, depths, and interfaces should be checked and which records are required. Include edge breaks, burr conditions, or protected surfaces where called for by the design.
Compare a complete milling scope
Ask each supplier to quote the same material, revision, quantity, finish, inspection, and delivery requirements. Confirm any secondary operations and exclusions in writing.
