Stropping V grind vs Convex

T

Trailer_Ape

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Jun 22, 2017
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First of all, wasn't sure if this should go in "maintenance tinkering" or not. If it is in the wrong place, please move it wherever it should be. Thanks.

Ok, got a decent strop a month or so ago but I never seem to get the results I want. If I use my K.E. with the Grinder attachment, I finish with the finest belt (included with the kit), stropping normally makes it LESS sharp. I have learned to just leave 'em be, once I finish.

Skip to today - My ESEE 5 was laying out, so was my strop. So I started playing around and OMG! It turned out amazing. So I am trying to find the difference between it and all the knives that I never really got right on the strop. I ruled out steel type because one of the knives that i could not strop to this level was the Izula which is the same steel with the same HT. The only difference I could think of was - the ESEE 5 was sharpened on my Edge Pro Apex while all the other knives were on the K.O.

So.... Should there be a significant difference in how well a V grind edge responds to stropping compared to how well a convex edge does?
 
When stropping a "V" grind strop at at 2° less than grind angle so as not to round over the edge as the leather is softer than the stone. A convex edge has a little more leave way on stropping angle. Stropping results should be equal if making sure not to round over the edge of either grind type.
 
That must be what I am doing. I just needed know - is it me or does a convex edge just not take to it as well. Now, I do, it is me.
 
It's easy to put too much 'convex' in convex-edged knives. And 'convex-edged' as a description, in my opinion, is a characterization that can lead one astray and degrade results. You really don't want to convex the edge itself, or any steel that even touches the edge. A good convex is more about the shoulders of what would otherwise be V-grind edge bevels. Convex the shoulders of the bevels, and keep the area near to and including the apex more crisp and V-shaped, of which the intersecting FLAT bevels will produce a keener, narrower and sharper apex.

All sharp edges should be essentially a V-grind immediately behind, and up to, the apex. If the convex goes all the way to the edge, the apex will be either rounded off or much too wide in angle, as compared to the grind angle just a little further back from the apex. This is why it often seems tougher to get a 'convex edge' sharp, and why results get even worse after stropping on a compressible substrate like leather. Stropping on a softer substrate, with compound, tends to round off an edge even more, unless the held angle is kept conservatively LOW (lower than the actual edge angle).
 
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That makes a lot of sense, thank you. Got it, shoulders are convex NOT the actual edge. Yep, that is what an apple seed looks like, makes sense :)

I just tried again, holding what I thought would be too narrow an angle. Seems to be getting better.

The rollers on my K.O. can be moved closer together, allowing less flex in the belt and creating less of a convex. Would it be a good idea to do that as well?
 
Trailer_Ape said:
That makes a lot of sense, thank you. Got it, shoulders are convex NOT the actual edge. Yep, that is what an apple seed looks like, makes sense :)

I just tried again, holding what I thought would be too narrow an angle. Seems to be getting better.

The rollers on my K.O. can be moved closer together, allowing less flex in the belt and creating less of a convex. Would it be a good idea to do that as well?
Click to expand...

I've always preferred a shallower (thinner) convex, if possible. So, I'd say that's a good idea. And a shallower convex also makes tasks like stropping that much easier, enabling the blade to be laid to the strop at a lower angle, which helps prevent rounding off the apex on the strop.

To me, the main benefit of a convex is in smoothing or eliminating the sharp & crisp shoulders of a V-grind's bevels, which reduces the tendency for the shoulders to get bound up or stuck in cutting thicker or very stiff material. And a shallower convex will improve on that some more.
 
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Thank you! I will move the two rollers closer together to create less of a convex.

I found out I wasn't going shallow enough, on the AD10, because the thumb studs is like a kickstand that won't let the knife go any shallower. I modified my technique a little - held the knife tilted (laterally NOT the edge) so that the entire edge is on the strop while the thumb studs is not. This allowed me to get a little more acute of an angle and, so far, it seems to be making a difference.

Guess I was just going to deep and rolling the edge.

I'm getting the hang of it :)
 
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