S125V 66rc Chopper

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HT 6 TF0_3DTG7@40%
S125V .308" thick, 66.5rc, 18 DPS, equiv edge thickness 0.018"
Chop test: woods includes Argentine Lignum Vitae, pork rib bone, beef rib bone


Edge after test - macro view
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Edge before & after beef rib bone chop test
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Your special HT might be very best but your knife design/making skill doesn't looks very well executed. I think it would be good for you to do HT service so the third party could also experience your special unorthodox HT.
 
Bluntcut, what level of polish did you take the edge to? sorry if I missed it but could not find that. It looks like 400-600 level.
 
Cobalt said:
Bluntcut, what level of polish did you take the edge to? sorry if I missed it but could not find that. It looks like 400-600 level.
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Good eyes! Apexed at 600 grit diamond plate, deburred (a few swipes) with DMT E then EE.
 
bluntcut said:
Good eyes! Apexed at 600 grit diamond plate, deburred (a few swipes) with DMT E then EE.
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I use to have a couple of heavy choppers, one made from 440C and one from ATS34, nether of which is ideal chopper steel. Back in the mid 90's choices were few. In any case, I used both to compare edge damage on hard woods. I ended up polishing the edges to 2000 grit and I was impressed at how much better the edge handled the chopping. Took far less damage. I knew it wood, but it was better than expected. I like 600 to 800 for large choppers that have tough steel. But if I ever own another weaker stainless chopper, I would likely go high on the polished edge. I wonder how much a difference that would make in your knife with s125
 
Cobalt said:
I use to have a couple of heavy choppers, one made from 440C and one from ATS34, nether of which is ideal chopper steel. Back in the mid 90's choices were few. In any case, I used both to compare edge damage on hard woods. I ended up polishing the edges to 2000 grit and I was impressed at how much better the edge handled the chopping. Took far less damage. I knew it wood, but it was better than expected. I like 600 to 800 for large choppers that have tough steel. But if I ever own another weaker stainless chopper, I would likely go high on the polished edge. I wonder how much a difference that would make in your knife with s125
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Agreed. My experiences are similar mostly to yours, except very keen edge would steer badly when chopping penetrate more than .75" into high density super hard woods such as katalox, african blackwood, lignum vitae, .. edge would buckle into big bent or half moon chip.

When HT6 is complete, I can try 1.2K diamond waterstone (which is equiv 3K diamond plate in term of polishing finish) on this 66.5rc s125v. At this point and given toughness didn't dropped too much and didn't gained more than 0.5rc, I project this chopper would overall out perform the result above. And would has crazy wear resistance even in chopping mode (harsh push-cut impact).
 
bluntcut said:
Agreed. My experiences are similar mostly to yours, except very keen edge would steer badly when chopping penetrate more than .75" into high density super hard woods such as katalox, african blackwood, lignum vitae, .. edge would buckle into big bent or half moon chip.

When HT6 is complete, I can try 1.2K diamond waterstone (which is equiv 3K diamond plate in term of polishing finish) on this 66.5rc s125v. At this point and given toughness didn't dropped too much and didn't gained more than 0.5rc, I project this chopper would overall out perform the result above. And would has crazy wear resistance even in chopping mode (harsh push-cut impact).
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Yes, the only place where performance would drop at a higher grit polish would be in slicing, draw cutting. The lower grit levels tend to work better there. But that's not much of a loss considering all the other gains.
 
bluntcut said:
Preliminary test at conservative 20dps (instead of 18 dps) and at 70% chopping intensity. Will do full 18dps test video soon...

Under 30x loupe - Apex lost some carbides from chopping Argentine Lignum Vitae.

Hi-res image

EoTRHIZ.jpg
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Brittleness can be cured by thicker edge bevel, low toughness can be cured by a wider blade. Now if you want a tougher blade, I suggest for your next chopper, you leave the first 3 1/2 inches from the hilt un-beveled. The 5-inch sweet spot at the front is all it needs.
 
hank_rearden said:
Brittleness can be cured by thicker edge bevel, low toughness can be cured by a wider blade. Now if you want a tougher blade, I suggest for your next chopper, you leave the first 3 1/2 inches from the hilt un-beveled. The 5-inch sweet spot at the front is all it needs.
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I concur, added strength can mitigate brittleness. Though, only added toughness can cure insufficient toughness.
 
Im behind your edge holding and edge stability tests, some of the steels you are testing are designed for wear reduction and strength.
I feel like most high carbide/large carbide steels will fail under lateral flexing. Ive seen steels like D2, A2, O1, M2, fail due to breakage in Bladesports.
 
elasmonut said:
Im behind your edge holding and edge stability tests, some of the steels you are testing are designed for wear reduction and strength.
I feel like most high carbide/large carbide steels will fail under lateral flexing. Ive seen steels like D2, A2, O1, M2, fail due to breakage in Bladesports.
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Sure, that is what often taken place when using conventional HT high carbide volume% under lateral flexing activities, such as chopping. In the video and closeup image of edge, this 66.5rc s125v subjected to a lot of lateral forces. S125V has very high carbide volume% - its spec: http://zknives.com/knives/steels/s125v.shtml
 
As an amatuer knifemaker, Ive been leaning towards Larrin's scientific test results, that don't always agree with your own, but your recent posts have been a great example of small batch testing and results.
You've inspiried me to test my own methods and processes, again,
Thin and hard is good!
 
FYI
This s125v is part of ht6 batch. HT6 Research takes ~10days and costly utilities and LN2. All these specimens going through ht 50+ sequences together (as a bundle) from quench to finish. Obviously, very little over-lapped with conventional ht 1-2 sequences/steps protocol.
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