The design tool developed addresses the need for timely and interactive manufacturing cost estimation early in product and process design. The particular context treated is finish turning of titanium. A collection of simple physical models of the most relevant phenomena are combined in a computer program. Model simplicity enables rapid delivery of results in the form of cutter temperature, force, and wear predictions. Knowledge of the specific nature of titanium machining is included. Cutter wear predictions agree well with experimental data. Process conditions and cutter geometry that result in minimum direct cost can be provided on time scales that are a fraction of the time to actually machine the part. This design tool is most appropriate for cost estimation of jobs in which cutters and/or machining time are a significant part of manufacturing cost. The tool can serve to identify robust process conditions and cutter wear limits in the sense that variation in machining cost for variations about the process operating point can be explored.