Use a new Grobet file or other top quality mill Bastard file. 10" preferred here. Proceed to set your desired angle forming a burr. Flip and use the same number of strokes on the other edge. make sure you form the burr! Next use a stone or diamond hone and remove the burr by alternating strokes using light pressure. Once sharp , use a strop (leather,cardboard, hardwood0 to set the edge to its final sharpness.