CNC milling is highly precise, capable of producing steel parts with tolerances as low as a few thousandths of an inch. The level of precision depends on several factors:  

• CNC Machine Tool: The accuracy and rigidity of the CNC machine tool directly impact the precision of the machined parts.  
• Cutting Tools: High-quality cutting tools with sharp edges and proper geometry are essential for achieving accurate and smooth cuts.  
• Programming: The CNC program must be carefully written to ensure accurate tool paths and feed rates.
• Workholding: The workpiece must be securely clamped to the machine table to prevent vibration and movement during machining.  
• Machine Calibration: Regular calibration of the CNC machine is crucial to maintain accuracy.  

By carefully controlling these factors, CNC milling can produce steel parts with exceptional precision, ensuring that they meet the stringent requirements of various industries.