Might be good for hogging out steel, I've got a few carborundum hardware store knife hones I use for exactly that purpose. But I would still recommend a good 1K stone to follow up with and help bridge the gap between your rough 400 stone and the C12K. I imagine it would be possible to work 400 grit hone striated out with a thick slurry, but I also imagine it would take a lot of time. I've done 2 stone with a 1K and a C12K, that isnt too terrible. I haven't tried from anything more coarse than that.