Clamping the Knife at an Angle

[cbwx34]

I've seen it before, but I was watching the "Tormek T-4 Bushcraft" sharpening class, and they made such a point of it, I thought I'd use it as an example.

In the video, Wolfgang shows clamping the blade in the normal manner (Picture 1), with the edge of the clamp parallel to the edge of the knife.

But then he shows (paraphrased here) that in order to properly sharpen the curved (belly to tip) area, he angles the knife in the clamp, parallel to an imaginary line from the heel to the tip (Picture 2).

Now the result of this in theory, would be to change the rotation point of the clamp.

But, when he goes to sharpen the knife, he uses their standard technique of lifting the handle to sharpen the belly to tip area.  No rotation involved.

Here's my thoughts on this...

As I said above, if you sharpen by lifting the handle, there is no need for this... it doesn't change anything, since the rotation point is at the center of the jig.

Using the imaginary line, especially on the stock jig setup, is not correct, even if you do rotate the knife to reach the belly to tip area, because it puts the rotation point in the wrong spot, and it also moves the rotation spot during sharpening (as you rotate the blade the rotation point changes).

Prove me wrong.

p.s.  The 2nd example actually originated from another clamp style sharpener years ago, in an effort to properly sharpen the belly to tip area... and worked more by coincidence than it did setting the knife properly.

[highpower]

I remember him using the same 'imaginary line' idea in the first knife sharpening video to align the jig as well. And they really stress the point of lifting the handle up vs. rotating it to keep the bevel even around the belly and tip of the blade. What I don't understand is why does he then in this video, do just the opposite on the honing wheel, and swings the handle completely around the radius of the belly to remove the burrs? 

[tgbto]

I'd add that by using the imaginary line, the natural tendancy of the jig will be to get back to the position where the flat part of the handle is flat against the support bar, as you keep pressing down on the jig handle. So you have to kind of fight this trend during your sharpening.

I actually thought that was the whole point of this: to make sure you're in control at every point in time of the angle between blade and stone, and not let the jig do it...

But if I remember correctly, in the advanced sharpening class, during the part where he adds the cardboard around the jig to show how it rotates, the jig handle is parallel to the flat of the blade, not to the imaginary line.

[cbwx34]

I'd add that by using the imaginary line, the natural tendancy of the jig will be to get back to the position where the flat part of the handle is flat against the support bar, as you keep pressing down on the jig handle. So you have to kind of fight this trend during your sharpening.

I actually thought that was the whole point of this: to make sure you're in control at every point in time of the angle between blade and stone, and not let the jig do it...

But if I remember correctly, in the advanced sharpening class, during the part where he adds the cardboard around the jig to show how it rotates, the jig handle is parallel to the flat of the blade, not to the imaginary line.

Good points.  You may be right, he may clamp at an angle so you have one point of contact for better control, and it would also simulate a "pin pivot collar" to some degree... but then they emphasize lifting the handle to reach the tip, which kinda negates that.

I'll admit, I've watched that advanced video a few times, (again this a.m.), and I really don't totally understand the point of the cardboard part.  It seems to me that he's showing the radius of edge of the stop collar, and using that to place the knife, which would make sense if you rotate the blade to sharpen the belly/tip area, using the edge of the stop collar as the pivot.  But when he demonstrates sharpening, he returns to lifting the handle, and that rotation is around the shaft of the jig.

[cbwx34]

I remember him using the same 'imaginary line' idea in the first knife sharpening video to align the jig as well. And they really stress the point of lifting the handle up vs. rotating it to keep the bevel even around the belly and tip of the blade. What I don't understand is why does he then in this video, do just the opposite on the honing wheel, and swings the handle completely around the radius of the belly to remove the burrs? 

Another good observation.  I think rotating the blade is a more natural movement, so he does it on the honing wheel, maybe without thinking about it?  Or, if honing freehand, you can feel and hear if you're at the edge, and adjust accordingly... might be easier to do rotating the knife.  Just guessing here... 

[Beaker]

I clamped a few knives "askew" per Wolfgang's imaginary line after that Tormek Live episode.  It felt very unnatural to me to not have the back of the jig support in alignment with the knife edge. Perhaps because I just hadn't done it this way before.  I tried it on a few chef knives, but rather quickly returned to clamping in alignment with the blade edge.  I use the handle lifting technique up and slightly away, rather than any pivot for knives that don't have a very substantial sweep at the tip. To summarize, I don't see any benefit in the "imaginary line" clamping technique.

Beaker.

[Arthur]

I clamp the knife in an "imaginary line" only when the knives are very short.

[cbwx34]

I clamp the knife in an "imaginary line" only when the knives are very short.

There is some advantage to this, if you pivot the knife to the tip, since it moves the pivot location.  But none if you lift the handle, that I can see.

[cbwx34]

I clamped a few knives "askew" per Wolfgang's imaginary line after that Tormek Live episode.  It felt very unnatural to me to not have the back of the jig support in alignment with the knife edge. Perhaps because I just hadn't done it this way before.  I tried it on a few chef knives, but rather quickly returned to clamping in alignment with the blade edge.  I use the handle lifting technique up and slightly away, rather than any pivot for knives that don't have a very substantial sweep at the tip. To summarize, I don't see any benefit in the "imaginary line" clamping technique.

Beaker.

Pretty much what I think too... it goes against the design of the jig.

[Arthur]

I clamp the knife in an "imaginary line" only when the knives are very short.

There is some advantage to this, if you pivot the knife to the tip, since it moves the pivot location.  But none if you lift the handle, that I can see.

Right!!! Since I sharpen knives primarily with laser guidance, the preferred way to stay on line is to turn the knife.