Comment by jabl
13 hours ago
> If I need a universal lubricant that is readily available and cheap, I just use used motor oil.
Why? Used motor oil is, well, used. It contains metal particles from the engine and combustion byproducts, which is why it was replaced in the first place. Granted, most lubrication applications aren't the marvels of precision parts moving at high speed that a modern engine is so can probably make do with poorer oil, but still.
You can buy industrial lubricants in bulk for pretty cheap so that unless you use huge quantities of it, it shouldn't make much difference.
As an aside, my aunt's husband worked more or less his entire career in a heavy truck repair shop. And he had an oil burner heating his house (you can see where this is going, eh?). So he got used engine oil for free, the shop was happy to get rid of it as disposing of it properly cost money. I think burning used engine oil was illegal already back then due to the pollution, and nowadays I think they have some government mandated accounting system to ensure that the same amount of oil is sent to proper recycling as comes in.
You're right about getting industrial lubricants in bulk for cheap. But I don't need 55 gallons of lubricant. I'd never use it all nor do I want to store it.
Used engine oil isn't really suitable for lubricating an engine anymore but it's fine for a temporary lubricant of a drill bit, some random hinge on a gate, or stubborn bushing on a piece of equipment. Engine oil is only really replaced on an engine because at some point it degrades enough that things like oil film bearings in the crankshaft would start to fail. A bushing on something like a small dump trailer doesn't rotate at 2300 rpm.
> You're right about getting industrial lubricants in bulk for cheap. But I don't need 55 gallons of lubricant. I'd never use it all nor do I want to store it.
Well, the corollary to that is that if it's just small case usage then if you buy a 1L bottle of some general purpose lubrication oil for, say, $5, then it doesn't really matter in the grand scheme of things that the price/L is a lot higher than if you buy an entire drum of the stuff. ;-)
> Used engine oil isn't really suitable for lubricating an engine anymore but it's fine for a temporary lubricant of a drill bit, some random hinge on a gate, or stubborn bushing on a piece of equipment. Engine oil is only really replaced on an engine because at some point it degrades enough that things like oil film bearings in the crankshaft would start to fail. A bushing on something like a small dump trailer doesn't rotate at 2300 rpm.
Fair enough. I guess I just don't see the benefit here vs just having some bottle of cheap unused lubricant. Except if used engine oil is the only thing you happen to have at hand.