Question about knife sharpening--not Kim Kardashian.

[Geoff in Philly]

I am a devoted knife guy. I have used every manual sharpener from Edge-Pro to the Sharpmaker. I am seriously considering a T7, primarily for my many folding knives, camp knives, kitchen knives and for my son to maybe earn some spare cash sharpening neighbors' knives.

The Tormek site shows a different method of sharpening the tip than your video. Assuming yours is the correct way, how hard is it to "raise" the tip by rotating the shaft and getting the exact duplicate on the other side. In other words, if symmetry is the goal, doesn't that lift/slide introduce error?

Let's say i want an 18* angle, with practice, do you just "feel" the lift/slide on each side of the knife?


EDIT: I suppose that depending on the amount of "sweep" at the tip, I could just slide the edge right across without lifting and just have a visually larger, ie steeper, edge  bevel...

[Jeff Farris]

Geoff,

It really becomes second nature once you do it a few times. If you think about the geometry, as the distance from the tool support to the knife edge changes, you're following along with it.

[Geoff in Philly]

Jeff, I am trying to visualize this...In your video, you always keep the black plastic knob  flat against the tool support and rotate the shaft (to raise the blade handle) while keeping the flange of the knob flat against the support. In the Tormek video, the operator doesn't lift the blade handle by rotating the shaft, but does that semicircular motion you say not to do.

As the distance to from the tool support to the knife edge changes, isn't the distance equalized by arcing the knife handle and not lifting it?.


sorry to be so thick...

                 

                             

[Jeff Farris]

All I can tell you is that if you do it the way the Tormek video shows, you will get a bevel that gets wider as you move along the curve. If you do it the way I show it, you will get a consistent bevel.

[Geoff in Philly]

I guess I'm gonna take the plunge!
thanks for your help.
Geoff

[Herman Trivilino]

As the distance to from the tool support to the knife edge changes, isn't the distance equalized by arcing the knife handle and not lifting it?.

If you arc the knife handle instead of lifting, it might be possible to keep that distance from tool support to knife edge constant, but I've never had success doing it that way.  Of course, the distance from the tip of the knife to the location chosen to clamp the jig is critical.

If, on the other hand, you lift the handle rather than arcing it, it's very easy to keep the bevel angle constant.  As Jeff said, you get a bevel width that's consistent.  I remember when I first saw the video of Jeff doing it that way, it was one of those "Ah ha" moments.

Think of it this way.  If you arc the handle, you've got two degrees of freedom.  In addition to controlling the arc angle, you must also control the lift angle.  The reason for this is that the flange on the jig is now in contact with the tool support at only one point.  If instead you lift the handle, the flange on the jig stays in full contact with the tool support, and you have only one degree of freedom to control, the lift angel.

You should also be aware of the fact that for your many folding knives, the blades will be too short to use the jig.  You'll have to free-hand them.  I don't recall if there's a video of Jeff demonstrating that technique.