1. ACCURACY Manual Tube bending: Operator error is a threat when bending tubes manually. Producing quality tube bends depends on the operator’s skill level. Any slip-up will end up in the waste heap. CNC Tube bending: Automated CNC tube benders adhere to a computer program that never deviates, as long as your vendor’s operator inputs the correct specifications. Barring a case of fat finger syndrome, you’re getting better accuracy with CNC.