Abstract: A method for manufacturing an endless track split master link consisting of forming a split master link process blank, machining the bores for the link pins to engage the adjacent track links and for accepting a securing apparatus, securing the process blank in an Electrical Discharge Cutting Machine tool (EDM) by placing mandrels in the EDM through the link pin bores, calculating a cutting path to generate complimentary fit-up faces between the link pin bores, storing the calculated cutting path in a memory in the EDM, actuating a cutting element along the calculated cutting path, emplacing a securing apparatus, and removing the split master link from the mandrels.

Abstract: Seismic probe more particularly usable in an untubed shaft comprising a central body and arms opening out radially in different directions. The end of each of the arms is provided with means for anchoring the arm on the wall of the shaft and geophones in a box. In one embodiment, each of the arms can be moved outwardly from the central body independently of the other arms.