The thing to bear in mind when you use Edge Pro's or Wicked Edges or even a Lansky system which all anchor the knife and have fixed pivot points for stones... or even polishing tapes...is that the angle of incidence where the stone contacts the edge is going to get smaller and finer the further away from the pivot point it is. This means you need to be careful where you clamp the blade and you also need to consider how often you need to move the clamp up and down the spine to keep things consistant.
If you check out a recent picture posted of a S5 with a mirror finish done on a WE you can see that the depth of the grind is steep at the ricasso end and becomes shallower towards the tip which in fairness on a 5 inch blade is not too noticeable but is not what you want if reaming a hole in wood with the tip...it is here you need strength...and ideally for a good edge it should be sharper towards the handle ( i.e. a little finer or shallower angle here for detailed work ) and a bit steeper towards the point.
This if done right gives you a consistant depth to the edge all the way along the knife's edge.
To see what I mean get a simple school ruler and a scientific calculator and when you clamp a knife to be sharpened measure the height from the centre of the spine to the pivot point where the rod device fits into. Then using the ruler measure from the pivot point to the edge. You will find if you anchor the knife in the clamp halfway along the blade and if it has a standard upswept point that it is shallower at the extreme end close to the handle...gets steeper as you approach the edge directly infront of the clamp and then a fair bit steeper as it reaches the belly of the curve and proceeds to the tip.
In larger blades this is very pronounced and therefore you need to work out where your "moves" along the spine need to be to keep the depth of the edge consistant....and thereby keeping the angle consistant.
We had a post a while back by a guy who was meant to know a lot about sharpening and you could see he had really thinned down his game warden which is not a big blade on the belly curve going up to the tip and the fine edge had "rippled" when cutting some wood. The edge was extremely shallow and the thinned metal was the result of sharpening....in his case freehand on a stone but not lifting the heel of his hand as the blade progressed along the stone to the tip to keep the angle uniform.
This same thing can happen if you don't move the anchor clamp along the spine to keep the angle within a sensible variation tolerance. To check variation use your measurements and height divided by length from the base of the clamp which touches the blade to the edge gives you a simple tangent...which if the inverse function is used on your scientific calculator gives you the angle of incidence the stone makes to the edge...
It is basically using measurements to give you a right angle "triangle" to work with so that a tangent can be determined and then the angle of incidence of the stone.
If you keep this in mind when using an Edge Pro or WE system and are getting razor sharp edges which are uniform in depth and angle....then you have cracked how to do a good "V" grind edge....:thumbup:
"Sharp" is still all you need
The difficulty with these devices....even using diamond stones is the time it takes...I have lost days of my life over the years trying to re-profile an edge on these devices....really they are great for touching up an edge which is a known one on "angle"....removing metal to re-profile to a finer edge takes "hours" and "hours"...that is why most people get discouraged....
To check for this use a magic marker on the existing edge and doing some light strokes see if the ink is removed right to the tip of the edge...if not then your angle is shallower than the original grind and you will be removing a fair bit of metal before the stone reaches the edge apex....
So better to increase the angle steepness if you want to just sharpen the knife....
Re-profiling an edge though can be done in less than an hour on a belt sander...making sure you cool the knife down between passes when the edge gets warm by dunking it in water...it is so simple and quick when you get the hang of the arm movement on the stroke so that you lift your hand as the edge comes to the belly curve and progresses to the tip...pulling the knife away before dragging the tip across the belt which will "round" the tip...that when you master this you will wonder why you did'nt learn this years ago....
It saves you "days" maybe even "weeks" over the course of your life:thumbup:
