wrench measures about 12 inches, 1 inch and 3/4 sizes, has 4 places with pressed letters  letters look like NMO, NMC or NMG, holding it with open end up, turned down letters read OWN ,  does any one know this logo, what is wrench used for. thank you 

I'm tempted to think it's a makers mark, more than a logo. Don't take that to the bank, though. Wait for somebody who knows some history about companies

thank you, 51 cub

Looks to be hand made probably owner/maker mark.