I'm curious if anyone could direct me to past discussions of these? I have acquired several and would like to find resources that would help me know more about these. Specifically a Clarke 612, a Royal SKM7, and a Tornado unit that fits on top of a 55 gal drum. I've spoken with folks at Clarke and they sent me a pdf of a parts diagram, I gave the Tornado to my brother for his shop, and the Royal came to me just this morning, and I know next to nothing about it.