when convexing

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blademaster01

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Jul 19, 2011
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when you are profiling a knife to convex ,is the goal still to get a burr at the edge,i watched a bunch of videos and of the ones i`ve seen,i understand whats going on,but i never see anyone check for a burr,seems to be random grinding
 
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Yes, but I don't stay on one side if there is alot of profiling to do. I'll try and keep count of my grinding strokes and then switch to the other side and repete. Just as an example I'll do 50 strokes on the right side then switch to the other side even if no burr has formed. Repete this until a burr fully forms on both sides. After you become more comfortable sharpener you can sharpen without forming a burr but truthfully I perfer raiseing a burr most all the time.
 
If your reprofiling a V edge to be convex you would want to repeat the same amount of strokes per side in order to keep everything even and ensure that both sides of your new convex edge reach the apex at the same time. Once the initial reprofiling is done and the edge is convexed and you begin to sharpen it, then you will raise a burr.
 
well, i am pretty sure i watched every,youtube video there is on convexing, and not one of them showed anyone mention a burr,also , many of them state ,its important to do the same amount of grinding to both sides , then go on to disregard thier own advice,hmm, makes me wonder sometimes
 
blademaster01, just listen to what Noctis3880, db and Menace have said and perhaps one day you'll live up to your name (no offense).
 
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i do a lot of convex edges and the knives i make are convex edges or on the chisel grind knives i make, they are a half convex edge. i use a belt sander but convexing by hand would be no different. go from side to side and when you have fully convexed the edge, a burr will appear and not before. if there is no burr, you need to keep going. sometimes if a blade is a little thinner along the edge than in other spots along the edge a burr will form there before anywhere else.
 
I can't speak for everyone who's posted YouTube videos, as anyone can do that these days. I'm sure there are at least a few who practice less-than-perfect habits, and then video their technique as 'expert' instruction.

A lot of experienced sharpeners, those who've been doing it for a long time, will do things almost by rote when sharpening. You might not always 'see' them deliberately look for burrs & such things, but by course of habit, if the burr's there, they'll notice it (believe me) and take care of it in quick fashion. Ever notice how many times a sharpener will just casually 'look' at the edge, perhaps by turning it upward to the light and rotating the blade back & forth? An experienced eye can usually see a burr or a blunt edge this way, just by looking for the reflected 'thread' of light coming off the edge. If the edge is fully apexed and burr-free, no such 'thread' of light will be seen. The thin, clean edge looks as if it 'disappears' under the bright light.

Another thing, depending on the steel type and sharpening method, sometimes burrs just won't be as much of an issue. Familiarity with how a particular steel performs & sharpens up will sometimes influence whether the sharpener looks for the burr or not. More 'ductile' steels (420HC, 1095, VG-10, ATS-34 come to mind) seem to form burrs & wire edges more easily, and they usually take more work to remove. On the other hand, I've personally never seen much of a burr form on steels like S30V or D2, especially if they've been heat-treated to higher hardness. Also, I'm inclined to believe it's easier to form a BIG burr on powered equipment (things happen a lot faster that way, both good and bad). I've done all my sharpening by hand in much SLOWER fashion (unpowered tools), and frequently inspect the edge as I go. So, I'm sure this explains why I haven't seen BIG burrs as much as some others may.

Personally, I inspect my edges under magnification to look for EITHER a burr or to see that the edge has been completely apexed. Doing some slow, observant cutting into some thin paper (like phonebook pages) can also be very effective in revealing burrs (which will snag the paper) or sections where the edge hasn't been apexed (edge slides over the paper). After all, it comes down to actual cutting under normal use. If the burr's there, it'll negatively affect how the edge performs. So long as one recognizes it when they see it, it can be dealt with in fairly quick fashion.
 
well, thanks for the input,i appreciate it, i`m going to give it a go,and we`ll see what happens, the knife,well ,its just a blade, is one i picked up at a garage sale yesterday for 75 cents,it is /was a scandi grind ,thanks again
 
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