Question: I wondered how many people wear a mask while sharpening at the grinder or sharpening stone?
Why I asked: I read there can be some toxic heavy metals in some types of steel used in chisels, plane irons and such. These can be additives used to help the steel achieve certain desired properties. So the specific metals and concentrations depend on what kind of steel you're sharpening (if I understood it correctly).
Thanks!
Fred