A bit more question answering. A2 is harder to sharpen that O1. It also must have a bit higher angle30-35 degrees or higher as has been mentioned. A smother also genrally has a cambered blade which on a BU plane will need a stronger camber than on a BD smoother. But still nothing like a Jack plane. At 2000 grit sandpaper you should have a decent edge(could be better but serviceable).