Case tru sharp edge holding?

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Mora2013

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Dec 1, 2013
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ive got 4 case tru sharp knives - a trapper with clip/wharncliffe, a mini copperhead with wharncliffe/pen, a sodbuster with clip, and a sodbuster jr. With clip blade.

For some reason, it seems that the trapper and mini copperhead edge holding is fine, but the two sodbusters seem to dull rather quickly.

The two sodbusters are certainly hollow ground knives, while the trapper and mini copperhead seem to be flat ground. All of them are at 40 degrees inclusive at the edge bevel.

I'm trying to figure out why the sodbusters don't hold an edge as well. They get quite sharp after stropping (leather, green compound), I don't see a wire edge. I'm at a loss.

Any advice? I'm thinking of even going wider on the edge bevel?
 
I know you said you didn't see a wire edge, but there might still be one.

Several of us have found that Case Tru-Sharp is prone to taking a wire edge. I certainly have. When I finish sharpening Tru-Sharp I strop it on my pant leg with a rocking motion. I try to catch any wire edge and bend it so that it breaks off. That seems to help a lot.
(Like you I use 40° inclusive for sharpening Tru-Sharp.)
 
Mora2013 said:
ive got 4 case tru sharp knives - a trapper with clip/wharncliffe, a mini copperhead with wharncliffe/pen, a sodbuster with clip, and a sodbuster jr. With clip blade.

For some reason, it seems that the trapper and mini copperhead edge holding is fine, but the two sodbusters seem to dull rather quickly.

The two sodbusters are certainly hollow ground knives, while the trapper and mini copperhead seem to be flat ground. All of them are at 40 degrees inclusive at the edge bevel.

I'm trying to figure out why the sodbusters don't hold an edge as well. They get quite sharp after stropping (leather, green compound), I don't see a wire edge. I'm at a loss.

Any advice? I'm thinking of even going wider on the edge bevel?
Click to expand...

Don't go any wider; in fact, go narrower.

The 40° inclusive edge angle is most of the issue. Any fine, wire edge formed will cut for a little while, after which it'll fold pretty quickly. Once that happens, the geometry behind it is all that's left; and 40° and higher doesn't cut well, or hardly at all, if the apex is no longer perfectly crisp. Try taking the edge down to 30° inclusive, or a little lower. It'll do a lot better, even after the apex loses a little bit of crispness. An edge finish of somewhere between 320 and 600 grit will also support clean slicing very well at that geometry, in Case's 420HC. The 'fine' side of a simple hardware store oilstone in SiC or AlOx is an easy way to finish it as such. Follow with light stropping with green compound on leather, or with bare leather or denim alone. The less burr there is coming off the stone, the less need there'll be for stropping with compound.

It seems counterintuitive to go narrower with somewhat softer steel. But with such edges, the cutting geometry doing the work is most of what matters in edge longevity. A wider-angled edge sustains it's shape longer, but it's a geometry that is doomed never to cut very well in the first place. The edge will still wear at the same rate, as it's a function of the steel itself and not the geometry. So, start it out with effective geometry that cuts better, and therefore longer than a wider, blunter geometry will. Additionally, thinner-edged geometry is also much easier to tune up, when it needs it.

BTW, I have two Case Sod Busters, one large and one small, in their Tru-Sharp (420HC) stainless. The above is more or less how I've treated mine (to varying degrees of finish), and it's made a world of difference in how satisfied I've been with them. I give the same treatment to all my other Case knives, as well as other makes & styles in similar stainless steel (SAKs, kitchen knives, etc), for the same reasons. They're all better off for it.


David
 
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Obsessed with Edges said:
Don't go any wider; in fact, go narrower.

The 40° inclusive edge angle is most of the issue. Any fine, wire edge formed will cut for a little while, after which it'll fold pretty quickly. Once that happens, the geometry behind it is all that's left; and 40° and higher doesn't cut well, or hardly at all, if the apex is no longer perfectly crisp. Try taking the edge down to 30° inclusive, or a little lower. It'll do a lot better, even after the apex loses a little bit of crispness. An edge finish of somewhere between 320 and 600 grit will also support clean slicing very well at that geometry, in Case's 420HC. The 'fine' side of a simple hardware store oilstone in SiC or AlOx is an easy way to finish it as such. Follow with light stropping with green compound on leather, or with bare leather or denim alone. The less burr there is coming off the stone, the less need there'll be for stropping with compound.

It seems counterintuitive to go narrower with somewhat softer steel. But with such edges, the cutting geometry doing the work is most of what matters in edge longevity. A wider-angled edge sustains it's shape longer, but it's a geometry that is doomed never to cut very well in the first place. The edge will still wear at the same rate, as it's a function of the steel itself and not the geometry. So, start it out with effective geometry that cuts better, and therefore longer than a wider, blunter geometry will. Additionally, thinner-edged geometry is also much easier to tune up, when it needs it.

BTW, I have two Case Sod Busters, one large and one small, in their Tru-Sharp (420HC) stainless. The above is more or less how I've treated mine (to varying degrees of finish), and it's made a world of difference in how satisfied I've been with them. I give the same treatment to all my other Case knives, as well as other makes & styles in similar stainless steel (SAKs, kitchen knives, etc), for the same reasons. They're all better off for it.


David
Click to expand...
Hmmm, has anyone else tried this? It does sound counter intuitive as you state.
 
I don't own a Case Tru-Sharp blade, but I'm curious to see how well they work. I look forward to seeing if this thread gets some more hits.
 
Pomsbz said:
Hmmm, has anyone else tried this? It does sound counter intuitive as you state.
Click to expand...

I have, though not with Tru-Sharp. It's not counter intuitive at all, it makes perfect sense. All OWE is telling you to do is to thin out the edge. I did just that with a GEC of mine. I once helped my nephew with his Boy Scout regatta project. The knife had the GEC angle on it and did nothing but crush the fibers of the balsa wood. That night I resharpened the knife, almost flat to the stone. It cuts much better now. As you can see that's not the stock bevel on that blade.

19701195148_ac7d3f74dc_c.jpg
 
Pomsbz said:
Hmmm, has anyone else tried this? It does sound counter intuitive as you state.
Click to expand...

It's basically what Buck Knives did, in changing their edge spec to 13-16°/side (26-32° inclusive, also in 420HC, BTW). It was part of their 'Edge2000' spec (think that's what they called it, or something to that effect, around year 2000). Through CATRA testing, they determined that a narrower edge angle actually performed better, for longer, simply due to the fact that cutting is much more efficient and less of a direct stress on the edge at a narrower angle. More downward force, into the edge, is needed at wider edge angles, which contributes more to edge wear and degradation.


David
 
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kamagong said:
I have, though not with Tru-Sharp. It's not counter intuitive at all, it makes perfect sense. All OWE is telling you to do is to thin out the edge. I did just that with a GEC of mine. I once helped my nephew with his Boy Scout regatta project. The knife had the GEC angle on it and did nothing but crush the fibers of the balsa wood. That night I resharpened the knife, almost flat to the stone. It cuts much better now. As you can see that's not the stock bevel on that blade.

19701195148_ac7d3f74dc_c.jpg
Click to expand...

I had felt it counter intuitive that it would hold an edge for longer with the thinner edge though Obsessed with Edges Obsessed with Edges explanation does make sense. I wonder where the cut off mark is, where additional slicing no longer allows more edge holding. Technically it would be an answer to rid the world of all the massively overbuild tactical style folders. That would be nice wouldn't it? :D :D
 
Pomsbz said:
I had felt it counter intuitive that it would hold an edge for longer with the thinner edge though Obsessed with Edges Obsessed with Edges explanation does make sense. I wonder where the cut off mark is, where additional slicing no longer allows more edge holding. Technically it would be an answer to rid the world of all the massively overbuild tactical style folders. That would be nice wouldn't it? :D :D
Click to expand...

The 'cut off' in edge angle, at the low end, usually seems (to me) to be around sub-25° inclusive for steels like this. I like taking my edges down to about 25°; but, if going much below that, I start to notice the edge becomes more fragile and vulnerable to rolling or denting (steels this soft won't chip). Still can be useful for light work, like slicing fruits/vegetables on a non-damaging cutting board; but you need to be more careful with it, and pick the tasks accordingly.


David
 
OWE is right. The thinner the edge = less resistance which requires less force= more efficient.
Primary bevel of 30 degrees with a 40 degree micro bevel is good for most duties a pocket knife will see.
 
Interesting notes about the thinner edge! When I sharpen tru-sharp I run the edge through a piece of pine wood to break off the wire edge after sharpening and then strop and it holds an edge fine.
 
I find TS will get a wire but a stropping on leather get's it away. I actually find their CV dulls quicker for some reason and more difficult to get it to take an edge with a couple of knives, no idea why. Heat treatment perhaps?
 
Ernie1980 said:
Interesting notes about the thinner edge! When I sharpen tru-sharp I run the edge through a piece of pine wood to break off the wire edge after sharpening and then strop and it holds an edge fine.
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This is what I do. I had a TruSharp SBJ and used it to cut ivy vine out of some window screens one day. About an hour and a half of cutting on some pretty abrasive material. It was still cutting by the end, although it needed sharpened. I think that's pretty darn good for that steel.

Also, I always like to sharpen the factory edge clean away. Not just strop, but remove a little metal. Case edges are definitely power sharpened and that tends to produce not nice steel at the edge. Definitely lower angles, especially since there's a little thickening behind the edge on that hollow grind.

Double also - with that Case TruSharp, I have found it's easy to overstrop and round the apex. TruSharp kinda likes a lower grit finish to have a grabby edge, doesn't need to be polished too high up there.
 
Try sharp is pretty good,easy to sharpen and holds decent edge.very good edc steel that can be sharpened on anything and it doesn't rust
 
I prefer try sharp over case CV ,edge holding is same and both are about equal to sharpen,that little wire edge is no problem to take off.all in all good edc steel and will be buying more case knives.my main edc for past couple months is slimline trapper in try sharp.excellent performing knife with bone scales
 
I am looking for your input on how well this steel from Case take an edge and holds an edge.

I found a peanut in abolone they produce new in the above steel but I don't know anything

about it. It would be for my girl and needs to hold an edge as long as possible.

Thank you ....

Jasmine is also a little confused.
54AFUlkm.jpg
 
You might check down the page just a bit for the thread "Case tru sharp edge holding?". Hope that helps.
 
traumkommode said:
I have found it's easy to overstrop and round the apex. TruSharp kinda likes a lower grit finish to have a grabby edge, doesn't need to be polished too high up there.
Click to expand...

Same here. I try not to strop TruSharp too much, or my edge is quickly ruined. I sharpen on a fine Norton India stone, and leave it with that nice toothy edge. Refining the edge further tends to leave me with a blade that dulls rather quickly.
 
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