I downloaded and read through the Ken's Clock Clinic "Tale of Oils" and they seem to recommend Mobil 1 SuperSyn 0W-40 or 10W-60 Extended Life oils. The Montgomery Clock movement in question is powered by a Synchron 1 RPM electric motor. This clock movement was OEM equipment for Schulmerich Electro-Mechanical/Electronic Carillons of the 1960s through the 1970s. All of the harnessing is hard wired (soldered). There are 57 wires to various wafer switches mounted inline which control the Westminster strike counts. When I first purchased the system in parts approximately 8 years ago and assembled it, I oiled the gear shafts with Hammond Oil which is SAE 15 Non-Detergent Turbine Oil. Obviously its on the thin side viscosity wise, but has had no ill effect on the metal parts.