The Grind

[Marko Tsourkan]

Just pulling your leg.

M

 

[jmforge]

It only becomes a hollow grind if you leave it in one spot on the wheel. Bill Moran ground his knives freehand on wheels both horizontally and vertically and they were NOT hollow ground. They were convex, but more subtle than ones done on a slack belt. From what I can tell, he basically did the blade in sections like a Japanese sword polisher does and then blended.

Murray uses a large round stone to cut the partial "flat" ground bevel. Because the stone has a curved surface, it is actually a little concave according to Jason. To me and my straight edge, it appears to be roughly flat.

 

[jmforge]

Actually, my blades tend to bulge in the middle when forged by hand. I have to go back and fix that.

Yes, forged knives often have "natural" convexing just from being hammered more in the middle of the blade. Sometimes they actually get thicker down towards the edge again from this, and their thinnest point ends up being in the middle of the blade (minus the actual cutting edge of course).

 

[tk59]

It only becomes a hollow grind if you leave it in one spot on the wheel. Bill Moran ground his knives freehand on wheels both horizontally and vertically and they were NOT hollow ground. They were convex, but more subtle than ones done on a slack belt. From what I can tell, he basically did the blade in sections like a Japanese sword polisher does and then blended.

As far as I know, all Japanese knife makers grind with wheels, as well and they are all convex on one side at least.

 

[jmforge]

and the single bevel knives that are hollow ground on the other side are done that way intentionally but pulling the blade along the wheel straight and letting the wheel dig into the center, for lack of a better explanation. Yet the same wheeel is used to produce a every subtle convex grind on the other side of the blade.I convex my blades by grinding on a KMG rotary platen and then flattening/thinning it out during hand sanding or on the flat platen if it is too convexed.

As far as I know, all Japanese knife makers grind with wheels, as well and they are all convex on one side at least.

 

[WillC]

1. Yes.
2. No.
3. It looks more "finished" and yes, to be able to "thin" the knife using the secondary bevel as a guide and then going to the primary bevel prevent a decrease in performance due to thickening of the blade behind the edge.

@Marko: Carter's bevels range anywhere from 1.4 cm to 2.5 cm in width. Del's heel area has excellent performance. He has been optimizing the balance of taper, secondary bevel angle/height toward the tip. I'm assuming that is why Salty is in the process of thinning down his bevels.

Thanks very much for wading through that! very helpful, in fact this whole thread has been most thought provoking. Oddly its making me want to give some traditional grinds a go. As I've not even tried them yet. I'm finding the idea of control with the beval parting food to one side appealing and would be interested in seeing how the slight hollow on the other affects things.