honing oil using on knifes?

When you use oil when honing a knife, the oil acts as a lubricant. It helps keep the metal in the knife's edge from heating up from friction as you grind/polish away very small amounts of metal to sharpen it. It also helps keep the stone from accumulating metal filings in its surface (which makes it harder for the stone to sharpen a knife). A final function is that the oil, like any oil on metal, helps keep a knife from rusting.

As for making your own, I suppose you could in theory make your own if you had an oil rig and processing plant in your backyard. Since most people don't have one of those, its easier to buy either machine oil, penetrating oil (WD40) or non-detergent motor oil and use that. Or you could simply use spit or water to lubricate the stone (though those tend to dry out/evaporate quicker than oil).

Are you using a water stone or an oil stone? It depends on what kind of stone you are using. I use water myself but when I do use my oil stones, I use the honing oil which is very light.

nothing to blade it protects stone also un loads filings from stone to wash away plus you already have best spit or saliva ,one of super lubes, out does most man mades follow up honing with leather strap or shoe top, that stands up feather edge and shaves hair though not very durable,

helps the knife grip the stone and easy to make sharp, any oil will work, 3and 1 works good

Just spit on it!