Convex Vs V edge on my becker

BePrepared

BePrepared

Joined
Aug 26, 2010
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so last night i decided to man up and put a polished convex edge on my BK7

i've noticed some interesting facts about this edge compared to the factory V edge.

The factory edge shaved better.

The Convex edge is MUCH better at cutting meat and shaving paper. The factory edge never really feathered light tissue paper, but the convex one does it like nothing.

The V edge FELT sharper to the touch, but i cut myself on the Convex edge and never even felt it... it didn't feel sharp then i was bleeding

So what gives? why does the factory edge shave so much better? It is sharper or is the edge geometry of a convex just not as good at that ?
 
It is not better or worse kinda deal. They are just different. I can shave (my face) with one of my convex edges, but I was never very good at getting a "screaming sharp" v-edge. I feel the convex is easier to maintain (strop after use) but others find the opposite to be true.
 
I really like a convex edge. I have put them on my 2, 14, and 9 and they really just work well. They seem to hold an edge longer and for me it is quite a bit easier to maintain like OLJ said. and on the big Beckers it seems to aid in the chopping a bit.
 
My Beckers currently have convex edges on them, I own both a bk7 and a bk5. For me, I think larger knives work great with convex edges, but I like my folders to have a V-edge.

I can shave hair with my convex edges when touched up, and polishing them up is almost as enjoyable as it is using them. When you strop your convex edges, make sure that you are not rolling the edge. Don't push down too hard or go at too high of an angle. The factory V-edge is sharpened at a fairly low grit, and the teeth do seem to shave quite well out of the box (in most cases). As to why it would shave better than a high polish convex? I don't know, but I know that some of my lower grit folders with v-edges are the ones that do best for me at work, on cardboard and plastic wrap, tape, etc. When it comes to woodwork, I like convex much better.

Kyle
 
the problem is, i literally can't get a sharp V edge on a knife. I have ruined good knives trying.

But i can put a VERY sharp convex edge on.

What i'm really wondering is why the V edge feels sharper and shaves better, but doesn't feather paper, or perform as well on actually cutting meats and leather

They both do well with all of them. The convexed edge performs MUCH better cutting THINGS but the V edge is the better shaver and feels sharper to the touch

why?
 
The V edge that feels sharper and shaves better is that from the factory? Or is it one you put on it? also are you talking different edges on the same knife or different knives? I think the ones that come from the factory have a lower grit (more rough) finish then are lightly polished. So these will have a toothier edge. Perhaps this is what you are feeling as sharper? It is my understanding that a lower grit finish then polishing almost makes micro serrations. Maybe that is why it is shaving better for you. Hopefully all that babble made sense. If not someone please correct me.
 
I am no expert, but I do know that a "V" edge and a convex edge has a very different edge geometry. I believe a convex edge is curved down towards the edge, a "V" edge is a sharp angle sloping towards the edge. The curved edge of a convex grind produces less drag, so that is why it cuts paper better, I have been able to get a good paper cutting "V" edge, but I think the convex grind is a better all rounder since it cuts better. I am no expert, but this is why I think this happens.

-orangish ducktape
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“Simplicate, and add lightness”
-Colin Chapman
 
lol it makes perfect sense. We're talking about the FACTORY edge on my BK7 (and about 5 other knives including all my kershaw folders)

I'm comparing performance and feel of the factory edge with my personally sharpened convex edge

i did extensive cutting tests before and after, and the above are my results/impressions
 
I'm not sure why your convex edge won't shave. I've convexed my 7 and 10, and both slice paper / newspaper nicely as well as hold an edge very well. Like Josh said, you just strop them to maintain the edge, and to me that's the biggest advantage I can think of.
 
Here is my take:

Factory edge "feels" sharper, because, if you look at it under a microscope, it has a VERY rough edge, ie, lots of edges to grab your skin & "feel" sharp.

A convex edge is polished to a mirror finish, so it is deceptively sharp, because, if you look at it under a microscope, it has a VERY smooth edge (yet is just as sharp or sharper), ie, NO edges to grab your skin & "feel" sharp. Thats why many people cut themselves on a convex edge. It is deceptively sharp.

An example: A guy at work (15 yrs ago & i no longer let anyone "borrow" my knife ) asked to borrow my knife, i gave it him closed & said, "be carefull, it is REALLY sharp." It was a small Camillus single blade, 1.7" long. He laughed & said "this little thing", he then opened it & slid his thumb down the length of the blade (who does that). I knew it cut him, but i saw no blood. He finished with it & gave it back. He stood there for a minute shootin the breeze with me & i saw it start to drip. It cut him pretty good. He never felt it because the edge was polished with a fine ceramic stone. Deceptively sharp.
 
I use my BK7 for chopping. How does the convex edge compare to the V edge in such use? Mine has a pretty sharp V edge, except for a couple of knicks in the edge resulting from gross buffoonery and failing to consider the background bahind my target, and a DMT sharpener generally fixes the edge.
 
Really it depends on what equipment/materials you have to work with. I convex all of my users with my belt grinder and keep them sharp with a strop. However, if I did not have either I would probably just keep my knives with a v edge and just use diamond stones to sharpen. Personally I like a convex edge because I feel like it cuts better since I can blend the edge into the primary grind and it is easier for me to keep my knives sharp. Some people find better results with a v edge, so YMMV...
 
I just use the back of an old belt on a bord. The compound i use is just a buffing compound I got from lowes or depot cant remember. It was only a few bucks and works great!

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good stuff...I guess what I'm trying to figure out is the following:

couple minutes ago roused BK5 from her sheath and proceeded to cut newsprint and attempt to shave a spot on my leg. Paper cutting OK, no go on the shave - so - I soaked my 800/4000 waterstone, then freehanded her on 4000, moving her blade back and forth working the her down the stone, did this about 4 times on each side, then did paper cut, better, then did hair shave MUCHO better. So, could I have achieved what I achieved just stropping? In other words did I remove unnecessary metal to achieve something that could of been done with a strop??? Thanks!
 
Problem solved... i put a drop of lansky oil on the extra find belt and ran my knife over it at an extremely shallow angle. It got an even better polish to it, and now it shaves just like my caping scalpel
 
convex edges go down to atomic levels and can sheer atoms :)
 
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