Mac:<br>the "v-shape" sharpener uses two opposed tungsten carbide inserts held in the "v" position. As you pull your blade through the carbides they strip fine shreds from your edge. This can be detrimental in the long term, and you cannot alter the angle of the edge produced. This is the system Wiltshire uses in their kitchen "Stay-sharp" knives.<br><br>Regarding sharpening serrations, I have found a narrow diamond hone slides up and down the inside of each serration (single side only) and across the blade rather than along it, so keeping a chisel edge inside each serration and doesn't grind down the teeth.<br><br>Hope this helps!<br>