Can I "flat grind" a native?

D

darthsoaker

Joined
May 2, 2006
Messages
1,273
I'm gonna pickup a Spyderco Native in a few weeks, but I was wondering if it is possible to flat grind a Native. If not flat, then maybe, um, flat-ish? :o

I have a Lansky sharpening system, a small medium-grit stone, and a Dremel. I know that last could destroy the knife, but threw it in just in case.

Thanks guys. :)
 
It is hollow ground. If you try to flat grind it you will probably lose 50% of the blade strength. I wouldnt even consider it.
 
ashtxsniper said:
It is hollow ground. If you try to flat grind it you will probably lose 50% of the blade strength. I wouldnt even consider it.
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Darn. :grumpy:

I think I still buy it, for $40, its a great deal. :cool:

If money allows, I'll have to buy a Centofante 3 for slicing.

Thanks for the help.
 
ashtxsniper said:
It is hollow ground. If you try to flat grind it you will probably lose 50% of the blade strength. I wouldnt even consider it.
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The question is, how much of that 50% is even necessary? The Native blade is .120" thick, and over 1" wide at the widest part. Assuming one could full flat grind from the spine to a zero edge, a fairly substantial blade would still be left behind. And would be a fantastic cutter. Any weakness would only be noticeable if the blade were used to pry laterally. Which is probably asking for trouble anyway.

However, a full flat grind is a lot of work. What I have done with mine is lay the hollow grind flat to the stone whenever I sharpen it. The idea is to thin out the edge bevel to near zero. If the hollow weren't so deep, it's be flat already. The result: thinner, more efficient cutting edge. No noticeable weakness observed.
 
Removed the hollow on mine. You need patience, a coarse hone, and the ability to ignore tired fingers. Or some extra dough and Tom Krein's phone #.
 
It is very difficult to do it properly without a belt grinder. I would leave it alone and buy another knife with a flat grind or send it to an expert--like Tom Krein.
 
thombrogan said:
Removed the hollow on mine. You need patience, a coarse hone, and the ability to ignore tired fingers. Or some extra dough and Tom Krein's phone #.
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Thom is right, as usual. I sharpened mine flat to the stone to get it to about a 7.5 per side edge, and had gotten rid of most of the hollow. Then I sent it off to Tom Krein for a high hollow grind and it is a real cutter now. I say go for it. If you don't have a belt sander a DMT XX Coarse and lots of pressure is highly recommended.

Mike
 
Ummm?? Doesn't suggesting someone work at getting a 7.5 degree edge on a S30V blade go against the high carbide theory? I do agree with a thinner edge, I like around a 10 to 15 degree per side edge, but 7.5 is kind of extreme. What is the reason for you needing or wanting a flat grind instead of the hollow grind?
 
db,

The actual cutting edge can/will/should be much thicker than 7.5 per side. Mine's in the 20/25 per side ballpark carbides be darned.
 
Thom is right, just sharpen it flat to the stone with a very course stone. A course, or extra course DMT diamond hone will work nicely if belt sanders aren't your style.

I've done this with many hollow-ground Spydercos and had great results. In particular my Byrd Cara Cara cuts notably well since being taken flat to the stone. Using this method the spine of the knife will still be just at thick, which helps retain a lot of lateral strength near the spine. The cutting edge side is still more prone to rolls, breaking etc. if you do stupid things with it though. The only thing that's damaged my Cara Cara so far is twisting a cut in some metal, which is my own fault. Still, only got a minute roll that's hardly visible after a steeling and light sharpening.
 
I say go for it, but I think I'd just thin and convex it freehand, versus trying to go all the way to flat grind it. I've done 'em both, though - sometimes you just gotta do what you gotta do. Despite the carbides, I've had good luck getting a nice poished edge on S30V with diamond paste on backed leather. Here's a thinned S30V yojimbo (weird but great handle!). I've used it cutting cardboard, tape, kydex,and the occasional jalapeno pepper. Admittedly not heavy use, but it has worked great.
---
that's a Krein TK-1 (in D2 :eek:) behind it...

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DSC05122.jpg
 
thombrogan said:
db,

The actual cutting edge can/will/should be much thicker than 7.5 per side. Mine's in the 20/25 per side ballpark carbides be darned.
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Yeah that is what I thought. Do you find you need that large of an angle? I think the dark side may turn on you with those angles. :)

I'm guessing but I think maybe Darthsoaker wants to use his Lansky to sharpen. I don't have a Native but I think the lowest angle on the Lansky, 17 degrees?, should do fine to sharpen it. To thin behind the edge I do much the same as Broos and grind free hand producing a convex. I hold around a 10 degree angle and scrub away. This produces an edge some place between 10 and 15 ish edge angle depending on how sloppy I am with the grinding.
 
db said:
Do you find you need that large of an angle?
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On that particular knife, I do. Otherwise, it chips out on the oddest things. Don't know or care why that's so (you know my theories, but they're just that as there's no room in the kitchen for an electron microscope), but the thicker final angle was the fix that sticks.
 
thombrogan said:
db,

The actual cutting edge can/will/should be much thicker than 7.5 per side. Mine's in the 20/25 per side ballpark carbides be darned.
Click to expand...

I'm assuming db had something to say about my 7.5 per side comments, seeing as you are responding to his posts. Mine uses a 15 per side microbevel on a 10 degree main bevel (after Tom Krein sharpened it to maybe 12 per side when he reground it), the 7.5 per side was just what the angle ended up at when brought the grind all the way to the edge sharpened flat to the stone. For cardboard it does fine at 15 per side, but edging lawns or doing other things that are popular around the Brogan household would lead me to a fatter angle probably to avoid chipping. When new that Native chipped out cutting thin cardboard until it was sharpened a few times, but it has been better since. The good thing about the .008" edge is that even with a relatively fat microbevel it still cuts really good.

Mike
 
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