Go Convex with Sharpmaker Stones, etc.

fulloflead

fulloflead

Joined
May 3, 2002
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Last night I was messing around with my Cold Steel Arc Angel that I sharpened freehand on some diamond stones.

It started out as a 'clean-up' job holding the Angel in one hand and a grey Sharpmaker stone in the other. Soon, I was putting a fantastastic polished convex edge on the Angel freehand with a Sharpmaker stone!

The stone goes in your left hand and the knife in your right, pointing away from you, edge-up with the edge canted toward about 2:00. Use circular motions with the stone with your finger on the back of it to add some pressure as you rock the knife edge back and forth from about 1:00 to 2:30 so you're working your way from the shoulder of the edge to the edge itself and back as you go up and down the edge.

If you work in good light you can SEE what part of the edge you're working on as it get's shinier. Later, switch to the white stones and polish some more.

I've got a near-perfect convex edge now that cuts like gangbusters!

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I've been yanking my Sharpmaker stones out of the kit and using them by hand on a lot of things lately. They're good for lots of things. On Spydercos with metal handles, I stick the point of the sharpmaker stone in the groove in the handle to remove the sharp, uncomfortable, corner that's there.


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Excellent advice!

Try finishing with the ultra-fines if you gots 'em.

Another thing you can do, if your knives have a thin-enough handle, is use the two slots on the bottom of the Sharpmaker to hold the stones as though they're a 1" wide benchstone and use them waterstone-style to quickly put a shiny bevel on the edge (the mediums leave a finer finish than when used in the Sharpmaker's slots).
 
This sounds like a good method to try. Can you post a couple pics?
 
That is similar to the method Fikes demonstrates in his video except he uses long strokes parallel to the edge with a huge diamond pad.

-Cliff
 
Cliff,

Is there a place to get this video you've refered to several times recently?
Thanks

cbw
 
Snow said:
This sounds like a good method to try. Can you post a couple pics?
Click to expand...

I sent it out to get the blade coated, so it'll be a while, and I'm not sure you'll be able to see anything when it get's back coated. That's a tough thing to get a clear picture of.

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Good post, thanks.

It always seemed to me that the double-bevel grind was the first cousin to the convex grind only much simpler to do.
 
I'm having lots of trouble sharpening my new Howling Rat. It came pretty dull and with an uneven edge at the tip, and I've been trying to sharpen it with no luck. I am doing the sandpaper and mousepad technique with 320, 600, and 2000 grit. I have read tons of links on how to do it including the BRKT FAQ, and to my knowledge I am doing it correctly, but it's still just not happening. I may just put a micro bevel on it with my Sharpmaker if I can't get it.
 
Don't move off of the coarse grit until it is very sharp, it can easily shave off of a much coarser finish. If the knife doesn't at least slice a piece of paper then the edges don't actually meet yet. Once it does then you remove the burr and can continue to finer polishes. You are probably also going far too light which is one of the main drawbacks to such a soft backing medium.

-Cliff
 
You mean pushing too little? I read that you should let it rest only on the weight of the knife, but I've been pushing down a bit, too. I guess I'll give it another try on the 320 and not stop until it can slice paper well. Thanks for the advice; I'll report back.

Edit: Also, should I alternate sides with each stroke, or do one side until a burr is formed, then switch? So far I have been doing 10 strokes per side or so, then switching.
 
Yes, any shaping, that means anything up to the point the edge meets and you form a burr should typically be done at really high force, I press very hard, 50+ lbs. On some knives with really hard steels which are brittle like some japanese knives you can't do this as the edges can blow apart under high pressure, this isn't the case here though. Don't do it on diamond hones either as it will wear the coating rapidly.

However if you press really hard on a mouspad it will deform and the edge will end up with an extreme curvature and cut poorly. The mousepad method is more suited to maintaining the edge. Grind the initial edge freehand, you don't need to be precise, just make the edges meet. Use a coarse stone and press hard, just eyeball the initial bevels if you want to keep that profile and reduce them otherwise.

When sharpening a full bevel I tend to go much more than ten passes per side because I would have problems getting a consistent patten if I was varying that much and plus ten passes doesn't do much of anything, I usually go 50-100 per side. When you are starting don't switch until you get a uniform burr.

When you are microbeveling however you have to switch very rapidly because you can apply an edge in under 10 passes total.

-Cliff
 
If you're pushing down with a mousepad, you're rounding off the edge and making it thicker than your Sharpmaker will like.

Lay the sandpaper on top of a phone-book, wooden board, or even a piece of glass/steel/tile. Less give; less rounding; more sharp (it'll still be convex; same if you use a benchstone and scrub it the edge on it like db does). Keep going in the way that's most comfortable to you (10 strokes per side or one side) until you raise a burr. When you are able to raise a burr on both sides (one side and then the other), lighten your pressure. Lightening your pressure will change how deep the abrasive will dig into the steel and because of that can help you remove or reduce the burr. Then, switch to a slightly finer grit and repeat. Lighter hands; harder backing for the abrasive.
 
I gave it a long time on the 320 grit and it's getting a bit sharper. It can now slice paper poorly! I might post a few pics of the edge and the angle I'm holding it at to have you guys see if I'm doing it right.
 
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