[Joe K]

For a while, 600W oil was (um) substituted with something else. There was complaints on the quart cans of oil everyone was buying from "proven" Model A vendors.

One of the nice features of working in a power plant is that "period" machinery frequently require "period" lubricants. One of these was ACTUAL 600W oil which was assured to meet the SAE standard. Quality Assurance was and is a major motivating force when up to $1M per day is lost on a unit outage. The standard number and grade was actually on a sheet glued to the top head of the 55 gallon drum.

This is the standard which has been revised bi-annually for many years. Automotive Gear Lubricant Viscosity Classification J306_201902 $92 and you too could own the actual standard.

Of course I grabbed a gallon or two while I was there.

I've mentioned the STP. In the punkin I use 600W oil. I feared that "slinging" of the oil on the gear would be impeded if I used STP in this application - and this might cause undue "working" of the oil - and consequent heating of the oil.

Which might "undo" the stick/pressure capability of the oil.

Dunno - it's not exactly rocket science. But it is nice to have "actual" 600W oil as an option.

Joe K