The old flat stone i have is pretty abrasive. If I had to guess I would say its between 700 and 1k maybe more. I watched my grandfather sharpen his old case pocket knife a bunch on it. I think its an oil stone but I really couldn't tell you that for sure either. The only thing I have ever used was water stones. I am afraid that if I tried to set the bevel on that old thing I'd do more harm than good because its only about an inch and a half or two wide and about an inch thick and 4 or 5 long. So as far as that goes I'd rather wait and buy a good 1k that i can put the full width of the blade on. Being new to honing straights I am trying to get into the right practice before I go experimenting with unknowns. I'm not new to sharpening just new to honing something that isffor cutting hair.