I'm trying to grind down an Opinel to a wharncliffe shape, but it's taking quite a while. I was wondering if anyone knew a fast way to go about doing this? I don't have any power tools or low-grit stones I can use. So far I've just been dragging the tip on a cement curb. It''s to a spearpoint right now and I think taking it down to where I want it would take at least 2 hours of dragging it on the sidewalk. Any suggestions?