Burr Free Sharpening Technique

[jasonstone20]

For me the term "burr-free sharpening" is a little bit misleading especially in discussion how it differs from "burr based sharpening". In my thinking more suitable term would be "burr minimization sharpening approach".
 
In my understanding burr is formed as a result of plastic flow after each cutting operation, regardless if edge-leading or edge-trailing technique was used.
 
In machining the burr formed during edge-leading cutting direction is called entrance burr while the burr formed during edge-trailing is called exit burr. Exit burr height is usually greater than the entrance burr.
 
Jan

Jan,
You are correct.  I think the term burr-free is used instead is because a burr is not purposely formed, or the goal of sharpening, and it's need for burr removal.  In the case a burr is formed, a micro-bevel is used to remove it, and since that is one of the normal final steps of burr-free sharpening (in the Cliff Stamp method), it isn't necessarily thought of as a separate step. Although for maximum edge sharpness, it is micro-beveling for micro-burr removal is used, then the knife is sharpened at the original angle again to remove the micro-bevel.

Jasonstone, thanks for your explanation!

My understanding how the burr is formed is shown in the attached sketch.

One might think that changing the direction of sharpening from edge-trailing to edge-leading will fully eliminate the burr, but strictly speaking it is not the case, because both burs were formed in a slightly different way. (I consider guided sharpening where the bevel angles are exactly the same for both sharpening directions. Results of free-hand sharpening, where the bevel angles are not exactly the same, may be different.)


 
Jan

Jan, 
Exactly.  That is the reason the edge leading passes are used, as it tends to leave a smaller burr.