This paper addresses a tool switching problem of a flexible machine with the objective of minimizing the frequency of movements of the tool transporter. A flexible machine must process a set of parts with its production sequence already prescribed. It is assumed that the tool magazine cannot hold enough tools for the parts. Thus, tools may have to be switched between two successive parts in the part sequence. Tools that are required but unavailable at the magazine are transferred from the tool crib by an automatic tool transporter with a limited carrying capacity. We suggest an optimal tooling policy utilizing the concept of early insertions of tools and show the effects of early insertions through computational tests on randomly generated test problems.