Hey Theresa, When it comes to black steel only getting the runners sharpened is really recommended. This device does not sharpen blades; it simply takes care of some of the smaller nicks in the blade to help the edge last a little longer. With that being said, this device could potentially slowly rub off that black coated finish that helps give black steel its performance benefits. It is for this reason that after sharpening black steel the sharpener will not use a hand stone to remove any burs. So while you CAN use this device on black steel, you run the risk of removing the black coating on the steel. Hope this helps.
Answer by: Kyle (Admin) on Dec 23, 2016 11:42:00 AM