BCMW ht 3V chopping tests

I agree - now, please come up with a marketing jingle for 2 aebl knives below :D

aebl 0.188 (3/16) thick, 1.75 wide/height, 64+rc

K1) look like bladesports shape, except front/tip is slightly curve for pry husk (especially brown).

K2) ffg big belly 3.5" blade for pressure cut green & brown coconut.
* I pressure cut quite a few green coconut with my little 65+rc W2 knife - need a strong thumb to push through the almost brown nut

Chris "Anagarika";16214276 said:
Luong,

The grind line on the video shows clean and flat. The chopper works well. With BCMW HT, a stainless (less maintenance concern) will be very desirable! :thumbup:
Especially for coconut processing, you don't want the patina blackened the nice white flesh;).
Click to expand...

edit: crank up the ht oven to cook aebl - the two .196", 1.5" wide, plus a couple paring. Dead aim for 66rc.
 
Last edited:
I am zeroing in my ht params(carbon+semi-stainless+stainless) - not random showing of hard-to-believe or yeah-right ;) videos.

Instead of 0.196" aebl, I ht-ed 0.138" instead because those blades + a 4 paring knives were ready.

Here is a 7 minutes video of a very thin chopper (or regular short machete). Just consider what a thin edge can & can't chop. Also, please keep open minded with my ht - high hardness is not mutual exclusive to toughness.

BluntCut MetalWorks 20160625
AEB-L 0.138" thick
0.010" - 0.016" behind edge thick
sharpened 15dps (30* inclusive) bevel

Chop: 2x4, oak board, pine, lignum vitae argentine

I state this chopper rockwell hardness at the end of the video. My camera auto-focus seems drunk :o

Thanks for watching & comments.

https://youtu.be/Rr-VeMCy1T4
 
Last edited:
I did this little test prior to the video above using a halt-tang field knife (5" blade, 8.25" OAL). It's a good insurance because metallurgical edge deformation, from multiple strikes some overlapping, is good toughness indicator and implicitly it has very low RA(retained-austenite) percent. Since high RA% in impact & movement would transform to brittle untempered martensite, sub sequence strikes would chip.

ADurh5K.jpg


edit to update: did more nail chopping - deformation exceeded uts (i.e. fractured/chipped). In daylight, I will try to take loupe+macro at fractured (a hanging chip - I want a recount :p)
 
Last edited:
Luong, that AEBL ate the wood like nothing. Do you know where I can buy one? Perfect for those coconut sessions :p ..:thumbup:
 
Last edited:
Loving this thread, and very interested in high hardness and toughness stainless, like your AEB-L.
 
Chris, thanks for the implied (either that or I have to finished my morning coffee before 'get it') brilliant marketing jingle - thin & hungry blade:thumbup:

Chris "Anagarika";16217641 said:
Luong, that AEBL ate the wood like nothing. Do you know where I can buy one? Perfect for those coconut sessions :p ..:thumbup:
Click to expand...

Thanks. I found at my ht 65rc - aebl is tougher than 3V. Yesterday, I made about 100+ chops into thin metal tube with half tang field knife. From the closeup pic above, you can see some small edge damages from that test.
black mamba said:
Loving this thread, and very interested in high hardness and toughness stainless, like your AEB-L.
Click to expand...

A few posts up - I aimed for 66rc aebl - missed by 1rc. Although, result is good, I think it could be better if I get nano hardness closer (wag of course) to 64rc and macro hardness to 66rc... Heating up ht oven for another aebl bake session - 2 paring (and if time permits a half tang 0.196" thick) knives. My dewar is running low.
 
ht today
2x aebl: 65rc (no improvement)
1x cpm154: 65rc (1st time with this ht)
1x s35vn: 62.5rc (1st time with this ht - will re-ht this one)

cpm154 paring knife - chop woods, etc -passed.

Limit testing

sreCcuZ.jpg


Per hanging chip from aebl half-tang field knife, here is a closeup

kQUoqVm.jpg


For those interested in cpm154 ht

CPM-154-Typical-MT.gif
 
Last edited:
I agree if your edges are stable at that high of rc.
I would take the trade of not trying to pry it lol.
 
bluntcut said:
No, I didn't and don't plan to test it. Perhaps wide plastic deformation zone & high ductility are not w/i my ht objective.
Dimensional geometry plays a huge role in bending/flexing - https://en.wikipedia.org/wiki/Young's_modulus
Click to expand...

Well I ask because I made some test too .Most with HSS steel with hardness above 64 HrC. I found that I can all day cut nail / hammer on spine / with no damage to the edge / convex edge / but if I try to bend blade more then say 25 degrees , adio mare .....will break like glass ? So what is the use of all that high hardness in your blade if they break in use ? There was MUST be are reason why Nathan the Machinist keep his 3V chopper about 60 HRC ......................
 
Last edited:
Cool, you are a ht tinkerer like me:thumbup: Please make thread & share your result - I am interested. As for bending/flexing test - please share your insights, especially metallurgical parts beside of YM's radius & thickness. Also what is your approximation BET & DPS of your tested convex edge?

From the 2 close up of edge failure mode images above - they show a lot of info about what happen to my ht edge when force exceeded yield: ripple and chip (corresponding to plastic & fracture) at very small YM radius and wedge cross section (variable thickness). Notice - absent of rolled because my ht steel has extremely narrow ductility window. Safely says I focus on flex & bend at 1-3mm radius and yet to learn the significant of flex & bend at 10cm-30cm radius. A 1mm thick, 300mm long, high rc, fillet knife will probably win in flex(at various radius) test among thicker knives.

Natlek said:
Well I ask because I made some test too .Most with HSS steel with hardness above 64 HrC. I found that I can all day cut nail / hammer on spine / with no damage to the edge / convex edge / but if I try to bend blade more then say 25 degrees , adio mare .....will break like glass ? So what is the use of all that high hardness in your blade if they break in use ? There was MUST be are reason why Nathan the Machinist keep his 3V chopper about 60 HRC ......................
Click to expand...
 
Natlek said:
Well I ask because I made some test too .Most with HSS steel with hardness above 64 HrC. I found that I can all day cut nail / hammer on spine / with no damage to the edge / convex edge / but if I try to bend blade more then say 25 degrees , adio mare .....will break like glass ? So what is the use of all that high hardness in your blade if they break in use ? There was MUST be are reason why Nathan the Machinist keep his 3V chopper about 60 HRC ......................
Click to expand...

I would say that he made his blade the way he did just so it wouldn't chip out as bad if you chopped through your wood and hit a rock .

Plus it's probably not worth the bad reputation to have a blade break in "the wild" as in a user's hands not in the hands of testers.

Bad news travels much faster then good .

I think of it as such .

You buy a knife with this high of rc because you want the preformance of a blade not a prybar.

But I see your side of it as well Natlek. As resistance to breakage is important.

But to someone that's not going to pry on their blade it wouldn't be much of a worry, am I wrong in thinking this way?
 
Perhaps best to understand these before having deeper discussion on merit (or lack) of bending tests:
https://en.wikipedia.org/wiki/Young's_modulus
https://en.wikipedia.org/wiki/Ultimate_tensile_strength
https://en.wikipedia.org/wiki/Stress–strain_curve
https://en.wikipedia.org/wiki/Toughness
https://en.wikipedia.org/wiki/Ductility

As I mentioned before, the 2 closeup images of the damaged edge show ripples = plastic deformation <= implied a good size plastic zone beyond elastic on strain curve. Chipped when exceeded UTS. i.e. this 65rc blade will flex within elastic zone -> set/plastic if passed yield point until and this zone isn't narrow (see closeup pics) -> fracture after UTS. I know, this topic can get twisty quick but understand fundamental of YM would clear a lot of misconception on what you see flex/bend tests out there, which are very little quantitative nor qualitative value on structural object.
For your reference/comparison - https://www.alphaknifesupply.com/zdata-bladesteelC-A11.htm

Hammer through 16d was a breeze, so I

6bkEfwQ.jpg
 
Last edited:
You must log in or register to reply here.
Back
Top