Owing to decreased development cycle timing, designing components for manufacturability has never been as important. Assessing manufacturing feasibility has therefore become an increasingly important part of new product engineering. This manufacturing feasibility is conventionally assessed based on static stiffness of components and fixture assemblies. However, in many operations, excess vibration represents the actual limitation on processing a workpiece. Limits on how far into components a tool can reach or the amount of processing time required to machine a feature is commonly decreased significantly due to vibration. Critical time is spent resolving these vibration problems during product launches. Depending on the machining configurations these vibrations can be due to the part & work support structure or due to the tooling & spindle assembly. This paper presents approaches for predicting the dynamic flexibility for either of these assemblies using purely analytical approaches. Results from experiential modal testing are subsequently used to validate the approaches shown. Also by predicting the frequency content of the cutting forces, the risk of resonance or harmonic resonance during machining can also be assessed. Combined, these methodologies represent a comprehensive approach to mitigating the risk of vibration issues during a machining launch using up front simulation during the part development and manufacturing process.