On May 4, 2:07*am, John Doe wrote:
I noticed a guy using a black permanent marker to mark the end
surface of a drill bit before sharpening it with a Drill Doctor. I
have used a marker to paint a chisel surface before sharpening the
chisel. Anything wrong with it? Anything better?

Thanks.

You can use anything that leaves a mark. I wouldn't use Prussian blue
because of the mess, though. You just need to see where you've been
and what you missed.

Stan