The practice of using tangible instruments in Mathematics was historically included in the work of mathematicians. In the Laboratory of Mathematical Machines, different types of activities with copies of historical geometrical instruments, called Mathematical Machines, are organized. The laboratory sessions, carried out in this Laboratory, follow a particular « laboratory format » that is a transposition of the idea of mathematics laboratories used in pedagogical studies, and also developed by the Italian Commission for Mathematics Teaching. In this article, after having explained in detail the various stages of a laboratory session, which has also been experimented upon by the workshop participants, some analysis elements of such activities are discussed.