The burr is almost easier to feel rather than see. My 43 yr. old eyes rely on the edge of my finger nail to feel the burr. I do not know if my eyes could detect it even in good light. Most of my slipjoints with various metal hardnesses will have a burr in just a couple of passes. It is remarkably fast. Make sure you figure what angle you want to use. I noticed if I wanted a "thin" profile, it took maybe 3 to 4 passes rather than 1 to 2. Have fun, start with a not so valuable knife, and you cannot go wrong. Say goodbye to all the hair on your arm if you test it that way!