Ok, so my post in NH has helped come up with some solutions for my plane work creating erroneously beveled box tops, but now I wonder what is the best method to accomplish this job in the first place.

What I am referring to is creating a small box (1/2" stock) and half-blinding the sides together. I generally have a 1/64 or 1/32 mismatch at the top and bottoms (not the actual dovetails themselves) and need to flush the top and bottom of the box.

I've tried laying a full sheet of sandpaper and rubbing the whole box over it. That works pretty well but can round the corners if the sheet catches. Planing with a small block plane I screw it up by creating an outward sloping bevel

So, my question is, what is the best way to flush boxtop corners up and still maintain a perfectly flat surface to accept the lid with no gaps?

THANKS

JC