Summary: Models are presented for determining economic processing speeds and tool loading to minimize the makespan required to produce a given set of parts in a flexible manufacturing system. Using Taylor’s tool life equation, models for determining the optimal processing speeds and the tools to be loaded into finite capacity machine magazines are formulated to minimize the maximum processing time in the system. These problems are evaluated for computational complexity, and several heuristics for obtaining good feasible solutions to the problem are discussed. The quality of the solutions obtained using these heuristics is evaluated by computational experiments against lower bounds established by either relaxations or optimal solutions when possible.