[DHZIEMAN]

My Dad from about 1925 on to 1965 made a living as a mechanic. He built a test set of the day, to check current, and leakage current (with a milliamp meter, along with lights for just plain continuity testing and as you can see from the pic's also distributor points with a heater motor with a single lobe cam on the shaft, that speed could be adjusted with a rheostat as well as spark gap of the coil. The unit also worked to test condensers. Clever! Today ya just go buy one or more to do these chores.