Burr: In engineering, a burr refers to the raised edge on a metal part. It may be present in the form of a fine wire on the edge of a freshly sharpened tool or as a raised portion on a surface, after being struck a blow from an equally hard, or heavy object.’ A burr, also called a wire edge, is created as a result of sharpening metal. The burr forms on the edge of the knife where the planes of the bevels (or, in the case of one-sided knives or chisels, the plane of one face and the bevel) intersect. The diagram below shows the burr projecting from the edge of the knife:
Parts of a Knife
Types of Edges
Straight or Flat Grind:
Edge Leading vs. Edge Trailing
Edge Leading is generally when sharpening with the edge going directly into the abrasive medium as you make a stroke. On the WEPS, an edge leading stroke would be with the paddles starting in a raised position and then pulling downward toward the base, or “into” the edge.
Edge Trailing is the opposite, or when the edge is behind the spine on the abrasive medium. On the WEPS, edge trailing is done when starting the stroke with the paddles closer to the base, and pulling in an upward direction or “away from the edge”.
As for when to use each, you can do edge trailing or leading when using any abrasive medium that is NOT a strop (diamonds, ceramics, Shaptons, Choseras), and you must use edge trailing for anything that is a strop (Balsa, leather, nanocloth).