S125V 66rc Chopper

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bluntcut said:
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.
5gL5GmZ.jpg
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Nice work...
And thankyou for sharing your rezultz we are all learning here.
 
bluntcut said:
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.
5gL5GmZ.jpg
Click to expand...
I think the testing is done my man, folks wanna buy em :D

Besides, we all know you have a beautiful wood collection that you have been hiding :p :D
 
DeadboxHero said:
I think the testing is done my man, folks wanna buy em :D

Besides, we all know you have a beautiful wood collection that you have been hiding :p :D
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:thumbsup: Shawn.

Making top-notch knives like yours take a whole lot knife making skills and sort of a perfectionist and high pain tolerance, so is it boot-camp time for me now :)

Hard to let them go when I don't have/hoard enough burls :p

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I renamed HT6 xyz to MS6 xyz. MS6 is on last sequence. I did 5 hrc readings for s125v chopper, averaged out 67rc. Which is 0.5rc higher than tested/video above. In a few minutes I will post MS6 other steels final hrc in my CWF thread.

This 67rc S125V will face 2 tests with 18dps and 15dps edge, I plan to video both.
 
bluntcut said:
:thumbsup: Shawn.

Making top-notch knives like yours take a whole lot knife making skills and sort of a perfectionist and high pain tolerance, so is it boot-camp time for me now :)

Hard to let them go when I don't have/hoard enough burls :p

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I renamed HT6 xyz to MS6 xyz. MS6 is on last sequence. I did 5 hrc readings for s125v chopper, averaged out 67rc. Which is 0.5rc higher than tested/video above. In a few minutes I will post MS6 other steels final hrc in my CWF thread.

This 67rc S125V will face 2 tests with 18dps and 15dps edge, I plan to video both.
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Good job on the testing man
 
Accidentally, I knocked bare chopper blade from grinder height onto concrete floor - bummer!

JMlshX0.jpg


Will do 15dps edge test on this 5.5" 67rc s125v blade 🙃

edit: Before re-profile, will try stick weld (keep blade cool) it together.
 
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I approached this with some skepticism, certain that there was no way a big S125V blade at that hardness was going to survive as a chopper. The results speak for themselves, I'm impressed.

That design is a MONSTER of a chopper. Looks sort of like an awesome mini parang. It sucks that that narrow section fractured, concrete has a way of wrecking things.
 
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gooeytek said:
holy crap. do you think that kind of failure would happen doing bladesports?
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I don't think so unless side-slapping/snapping the blade against some thing fairly rigid. Otherwise in normal use/competition, probability for this kind of failure is very low. I think, a good chance high end competitive blades probably fail if drop onto concrete from 3+ ft high.

tinfoil hat timmy said:
that looks like a sugar cube!
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Yeah sweet it is 😋

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I ordered a low-mid stick welder (noob time), hope keep chopper at full length...

My optical metallurgical microscope table doesn't support big specimen, took 400x pic at 75* tilt (15* from vertical) - each black blob(negative of a raised surface) is fuzz outline of a fractured grain (actually subgrain). Later on if of value, I will break a small piece of the edge to snapshot 400x normal/perpendicular to the fractured surface.

NKKImjw.png
 
Stick weld didn't worked - it cracked in front and behind the welded line. Well, 5.5" blade still a weighty 15oz.

Validating research result with very thin edge geometry
67rc S125V 15oz, 15 DPS, 0.008" Behind Edge Thickness
Sharpened with edgepro up to 1200 grit diamond waterstone, deburred with DMT EE

10:32 video

Edge overview after test

PDXALGt.jpg


Closeup

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bluntcut said:
Accidentally, I knocked bare chopper blade from grinder height onto concrete floor - bummer!

JMlshX0.jpg


Will do 15dps edge test on this 5.5" 67rc s125v blade 🙃

edit: Before re-profile, will try stick weld (keep blade cool) it together.
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Accidents happen..........but bluntcut my friend ,next time don't grind the bevels /plunge in that sharp angle. You need a good radius there , especially on that hardness and steel used...............that radius make huge difference , believe me . The knife is not just a edge of blade :thumbsup:
8Zw2gn9.jpg

fIaCDYb.png
 
Natlek said:
Accidents happen..........but bluntcut my friend ,next time don't grind the bevels /plunge in that sharp angle. You need a good radius there , especially on that hardness and steel used...............that radius make huge difference , believe me . The knife is not just a edge of blade :thumbsup:
8Zw2gn9.jpg

fIaCDYb.png
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Agreed. Large radius would reduce/minimize stress/fracture riser.
However I'm not sure a unground 67rc s125v blade would survive a drop onto concrete on its flat side. Well, I've no intention to find out anytime soon.
 
Finding out this instance of my research S125V 67rc edge impact capability...

Edge geometry: 10 DPS, 110 micron behind edge thick

Chop test: 2x4 Douglas Fir, Eucalyptus, Argentine Lignum Vitae

9:02 video
 
not sure if this steel can be stick welded, TIG would be more promising. otherwise treat it like cast iron, preheat severely, use specialized electrodes (probably not nickel tho) and hammer welds immediately (that is either work with helper or stop&hammer every 20-30mm).
did it crack immediately after welding?
 
outlandish710 said:
not sure if this steel can be stick welded, TIG would be more promising. otherwise treat it like cast iron, preheat severely, use specialized electrodes (probably not nickel tho) and hammer welds immediately (that is either work with helper or stop&hammer every 20-30mm).
did it crack immediately after welding?
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Did a 6" drop test on 1st weld = broke behind welded line. 2nd welded together. Chop (with slight slap) test = broke in front of 1st welded line.
TIG seems impart a little less heat on the interface but most likely won't work for this high alloy & carbon steel.
If research need another proof-of-concept specimen, I still have 15.5" of s125v bar to make another 10" chopper. For next batch, I already has a 7" s125v blank/chomper.
 
well you'd probably get the same result with any hypereutectoid steel. welding results in local coarse grain + untempered martensite, without post treatment (hammering, normalizing, tempering. not to mention hydrogen absorbtion issues) it is almost like grinding a notch into the blade - guaranteed fracture line.
 
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