Convex edge + Sharpmaker = ?

JR88FAN

JR88FAN

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May 5, 2013
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I have searched this one, and can't find any useful info so any feedback is really appreciated...

I am very comfortable on a Sharpmaker, and while I fully realize it's not the tool to retain a convex edge, I am going to stick with it. What do I need to know if I am going to sharpen a knife that has a convex edge?

From the limited info I have found, I will end up flattening it out.

I am OK with that, but is there a horrid process I will be facing to hit that edge before I finally flatten it out?

The steel is 3V. (I find 3V to be as easy as it gets to put a really good edge on with the SM)

If you've been down this road, or understand the dynamics of what the process will be, I would love any feedback..

Thanks in advance.
 
I have done that. Depending on the style of convex, it may take a stupid amount of time.
Try this: give it a couple of swipes at your finishing angle. If the marks are close to the edge, just keep going.
If the marks are a long way from the edge, you will need to take a lot of steel off, so I would use a coarse bench stone to thin it down first. Then go to the SM.
 
Can I not adjust my angle to hit the edge?

I have knives that are not at 15 or 20DPS, but I just use a sharpie and adjust until I hit the edge, then it's just muscle memory from there...
 
Maybe I mis-understood you, and this has something to do with actually being able to hit the edge because of the grind mixed with the limitations of the SM?
 
It's something you have to work out on your own. Saying you have a convex edge doesn't say much. It could be a convex edge that is virtually identical to a V edge, or it could be an extremely obtuse convex edge that is far from a V edge. Convex edges come in as many different forms as the the people who sharpen them.

The other complicating factor is that a convex edge will normally be the most obtuse near the apex.

I'd play it as you find it. Use your Sharpie to see where you're hitting on your edge. If the 40-degree stone is closer, use that angle and sharpen the edge until you raise a burr. Then remove that burr carefully.

I wouldn't try to freehand it with a Sharpmaker. If you're going to take that approach, there are much, much better ways to freehand.
 
Thanks for that advice. I guess I am just going to have to play around and see what I have and find a way to
Work with it.

Again, thanks for the info.
 
I'd look at this if you haven't already done so.


[video=youtube;nnkl1BRRrSQ]https://www.youtube.com/watch?v=nnkl1BRRrSQ[/video]
 
There is a tool called the worksharp which works really well in my opinion. There are two variations, the original and the Ken onion. The original works fine for me but at some point I will get the onion edition. Very easy.to use and puts a great edge on knives. This might help you and being a belt it maintains your convex edges. Plenty of reviews on youtube for you to check out
 
Moved to MTE, for sharpening discussion.
Best way to convex a knife edge is to use sandpaper and a mouse pad.
 
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