Demystified asymmetric knives

[Leo Barr]

I have to say I have been mislead by various articles on the subject.

An asymmetric knife will have differing grinds from the spine to the edge anything from 100/1 on a right handed knife the left side will be flat and the other side will have an angle 1st diagram
2nd diagram 50/50
3rd diagram approx 70/30

All have the same bevel angles.

Imagine a vertical wall (perpendicular to the ground this represents the spine) the bevel angle is relative to the perpendicular line. now imagine the other side of the wall slopes away from you the same angle is used for the bevel but the bevel will be wider .
I cannot describe it much clearer but this is how it is worked .
So no worries about differing angles if the knife is ground asymmetrically then you can use the same angle on each side to maintain the asymmetry .

Thats it !!!!!

Attachments:

• Scan2.jpeg

[Pat]

you can use the same angle on each side to maintain the asymmetry.

Not sure I agree with this. There are two types of asymmetries: 1) Asym grinds, so as a true chisel grind like a lot of DDCs and EKIs; 2) asym beveled knives like MSC performance series PTs and SnGs which are ground equally, but with one side unbeveled to the edge, the opposite beveled at some angle.

If I am understanding your conclusion, then you can ask Clay whether when sharpening EKI chisel ground blades if he uses the same angle on each side to sharpen. Of course you can do that, but you will deform the chisel edge.

Perhaps I am not understanding your conclusion.

[Leo Barr]

Ken’s video demystification

[Aaron kimpton]

You are saying as long as you do not adjust the center line you can use the same angle as shown on image 3 through out the life of the knife to keep the asym the same? To adjust it to 60/40 you would have to figure out the correct layout for the centerline and sharpen accordingling?

[Steven N. Bolin]

So, if the centerline isn’t moved, to keep a 60/40 asymmetry maintained you’d stroke a 6:4 ratio on each bevel?

[Aaron kimpton]

So, if the centerline isn’t moved, to keep a 60/40 asymmetry maintained you’d stroke a 6:4 ratio on each bevel?

From what I gather, that would create steering issues.

What i meant by the center line is the central axis of the knife as it cuts. If you were to do what you mentioned and could keep each stroke same pressure removing same amount the bevel would be off center.

to achieve a 60/40 on the 70/30 knife You would have to re imagine the centerline, figure out the correct bevel angles based on the new imaginary center line and cut/sharpen to that to create a knife with out steerage issues.

To be fair i am coming up with this out of a rudimentary vodoo practice involving small animal sacrifice… So take it for only what you paid for it.

[Steven N. Bolin]

So, if the centerline isn’t moved, to keep a 60/40 asymmetry maintained you’d stroke a 6:4 ratio on each bevel?

From what I gather, that would create steering issues.

What i meant by the center line is the central axis of the knife as it cuts. If you were to do what you mentioned and could keep each stroke same pressure removing same amount the bevel would be off center.

to achieve a 60/40 on the 70/30 knife You would have to re imagine the centerline, figure out the correct bevel angles based on the new imaginary center line and cut/sharpen to that to create a knife with out steerage issues.

To be fair i am coming up with this out of a rudimentary vodoo practice involving small animal sacrifice… So take it for only what you paid for it.[/quote]

I’m referring to maintaining the edge at a high grit once the asymmetrical foundation has been laid.

[Aaron kimpton]

so once you have changed the 70/30 to a 60/40 by adjusting the centerline? then maintaining it at a 6/4?

[Steven N. Bolin]

so once you have changed the 70/30 to a 60/40 by adjusting the centerline? then maintaining it at a 6/4?

From what I understand, moving the centerline is what causes steering issues on a knife with asymmetrical geometry. Regardless of the geometry the centerline should be left halfway between the width of the spine.

[Aaron kimpton]

I agree, my point is if you have a knife with the 70/30 split shown in image three. You then take that 70/30 and try and make it 60/40 based on edge bevel alone you will have an edge that is off center. I may be missing something here. I don’t see it as possible with out adjusting the centerline to be able to make a 60/40 split. To be honest i think both ways would be a poor substitute for a actual knife with a 60/40 spine. Trying to make a 70/30 a 60/40 is probably a stop gap, not a solution.

[Author]

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