The Ordo Machinum is an Ordo of the Inquisition. Overseeing the Adeptus Mechanicus, they are primarily concerned with the reintegration of recovered STCs into the Imperium's armies and the rare adaptation of alien technology into the established Mechanicum protocols. They ensure that laxness on the part of the Mechanicus does not permit a flawed design to enter Imperial service and more importantly prevent a greedy Magos from withholding vital designs for himself.
Inquisitors of the Ordo Machinum often accompany Mechanicus archaeological teams to distant worlds, monitoring their recovery and analysis of STCs. Thus, they often work in concert with the Ordo Xenos - especially when the world in question has been under alien control or there is any suggestion of non-human origin for the technology the Mechanicus intends to recover.