Case Tru-Sharp vs. Case CV

knarfeng

knarfeng

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So there was this thread in Traditional about CV steel.
http://www.bladeforums.com/forums/showthread.php?t=592586

Then Tru-Sharp got mentioned.
Then the question of which was really better.
Then the question of how hard were they.
Inquiring minds wanted to know.

oh, oh.

I bought a Case Mini-trapper in Tru-Sharp and a Case Sodbuster in CV. Both had the yellow synthetic handles.
The Sodbuster felt rather gritty as I moved the blade. Added some triflow (oil with Teflon particles) to smooth it out. It was still a bit stiff, but got rid of the gritty feel.
The mini-trapper was smooth and solid from the get-go. Nicely built. Very solid with good fit and finish.

OOB sharpness. Both very sharp. The CV would push-cut newspaper at the place where I held it. The mini-trapper would not, but was still very acceptable for sharpness.

I slipped by the metallurgical lab at work and borrowed use of the Rockwell tester. It is a nice machine with digital readout. It is recalibrated every 6 months to a standard traceable to the National Standard.

CV was 54HRC
Tru-Sharp was 55 HRC.

Reality check.
I note that the AG Russel web site says that the hardness of Tru-sharp blades runs 54-57 HRC, so my results sound normal.

So, that being said, how do they compare to one another in edge retention?

In making cutting comparisons between alloys, I prefer manila rope to cutting cardboard. I sharpen to a set angle, cut a set number of cuts using a set length of the blade, then examine the edge with a hand lens looking for damage. Normally I use 3/8" diameter because that is what the local HD carries. The advantage to rope is that it eliminates the effect of blade shape. As the rope fibers are cut, they pull away from the blade, so the only variables are the steel, the edge angle, and the sharpness.
I use a Sharpmaker to set a uniform 15° on the blades I am testing. I sharpen on the coarse until I can see no edge under a 3X lens, then move on to the fine.

I have a simple test fixture that consists of two boards side by side with a small gap between them. I cut the rope over the gap. That way the rope is supported, but I do not dull the knives on anything but the rope.
For this comparison, I made 10 slicing cuts, using a 1½" section of each blade to slice through the rope. Then I looked at each edge under a 3X lens using a high intensity halogen light to look for damage.

I repeated the process 3 times. The CV showed less damage in each case. The CV stayed sharper.

I might add that while both were REALLY easy to sharpen and both took a really great edge, the CV was easier to sharpen.
 
It's really amazing that the two different steels were so close in actual hardness. I wonder if the vanadium content of the CV makes it somewhat more abrasion resistant, therefore a longer lasting edge??
 
That sounds more like what I'd expect regarding the RC of the carbon steel, rather than the 59 that was mentioned in the linked thread. Sharpening my Peanut has felt similar to sharpening a SAK.

Is the composition of tru-sharp mentioned anywhere?
 
Phil, I do not think there is enough Vanadium in CV to form Vanadium Carbide to any significant extent. But I am not a metallurgist, so I cannot say why the performance was, only what the performance was.

Hi Vivi,
The composition of Tru-Sharp is unknown.
It performs about like I would expect 420HS to perform, if it were hardened to 55. More I cannot say.
 
Very well done. Your test shows the same as my daily use has shown me. I always thought that the big plus to carbin steels vs stainless is the ratio of sharpening ease to edge holding. So even if the edge holding was the same for both the easier sharpening steel pulls ahead in my book.
 
Nice test, thanks! The Case CV steel has some potential, I wish they'd make it harder. I don't think it would be harder to sharpen, given their high hollow grinds, but then again, I'm always on a quest for more edge holding...

They are easy to sharpen, though, and that's a good thing!
 
knarfeng said:
The composition of Tru-Sharp is unknown.
It performs about like I would expect 420HS to perform, if it were hardened to 55. More I cannot say.
Click to expand...


Frank, that seems about right since from what I have been told the Tru-Sharp is a 420 series steel that receives a good heat treat in an effort to achieve a reasonably high level of performance.
 
Thanks folks.

I apologise for the Typo in my response to Vivi. Should have said "420 HC".

(I used to work for a paint company whose flagship polyurethane topcoat was called "420 HS". My brain must have missed a cog when I was typing last night.)
 
Useful investigation and very well written thank you:thumbup:

I'm keen on both CASE steels as they offer good value for money and very reasonable use.
 
I bought sodbuster jrs in both steel and noticed similar results the CV lasts a little longer but both are very easy to resharpen.
 
The gritty opening of the blade is because when polishing with a buffer, some of the rouge got into the space between the blade and the handle. I used a power car washer to jet out the grits. Works smoothly after that.
 
Nice review of the Case CV and SS. I too am a fan of Case knives. There is one advantage of softer steels other than being easy to sharpen and that is stroping. Stroping has a greater effect on softer steels than on harder steels.
I've noticed that the simple act of stroping (after a few strokes on Sharpmaker 15 degree fine) on the leg of my blue jeans makes my Case knives even sharper.
 
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