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Extreme Lateral and Tip Strength

Posted by Ryan Nafe 
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Re: Extreme Lateral and Tip Strength
August 09, 2020 06:38AM
An interesting thing I’ve noticed is that I’ve never seen a picture of a Fallkniven that has a blown out primary grind. All the damage is always localized to the apex or secondary edge. Even when the edge angle is very high like 20 DPS or more, which is usually strong enough to force damage up into the primary grind of most knives, it just doesn’t seem to happen because of the lateral strength of the grind.
cKc
Re: Extreme Lateral and Tip Strength
August 09, 2020 08:43AM
yeah. even old videos chopping rocks have shown edge damage normally

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It's not Cliff, its Dr Stamp
#kebabstickcut, it's a thing - make it happen
Re: Extreme Lateral and Tip Strength
August 09, 2020 09:16AM
It might be part of why people say that the VG-10 is prone to chipping and that sort of dramatic damage. VG-10 is definitely much more prone to that kind of damage than 1075 is, that’s just a metallurgical fact, but the near-invulnerability of the primary grind may make it seem even worse than it would be otherwise.



I’m quite near to making the video. The stockpiled materials were all cut in the last couple days.
cKc
Re: Extreme Lateral and Tip Strength
August 09, 2020 10:37AM
Funny. it was Cliffs Video on the Spyderco Hossum Knife in n690 (v10 equiv) that got me to send the very first test knife to cliff to compare with it. i mean sure it is not as tough as 1050, 1075 etc, but its also not a steel that will just flake out on you. i was extremely happy with the performance from it in an outdoor knife.. but i just don't like the sharpening regrinding effort on any of the higher carbide steels

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It's not Cliff, its Dr Stamp
#kebabstickcut, it's a thing - make it happen
Re: Extreme Lateral and Tip Strength
August 11, 2020 07:51PM
Quote
cKc
i was extremely happy with the performance from it in an outdoor knife.. but i just don't like the sharpening regrinding effort on any of the higher carbide steels

Yeah I think it’s perfectly fine for an all-around utility/outdoor knife, especially since I can’t really do any chopping with it. In something the size of the S1 I enjoy it for its corrosion resistance and ability to keep cutting with a coarse finish for a really long time.

Where I’d rather have something completely different would be in their A2, Modern Bowie, NL1 Thor, etc. For a chopper it’s not something I’d prefer at all. Their A2 is a really appealing knife to me and I’d really like to buy one and just see what I find it useful for. It looks like it has solid chopping performance relative to its size, while also not being so large as to be useless for things like cooking, cleaning fish and game, and some of the finer tasks in camp/shelter making. But it’s a bummer that they’re using VG-10 because I just don’t wanna deal with something like that in a blade that’s really likely to see frequent contact with the ground.
Re: Extreme Lateral and Tip Strength
August 16, 2020 01:16AM
The tip broke while digging in a dead tree.

It took what looked to be about a 5 degree bend in the last 0.100” of the tip, and then broke after continued digging, losing about 0.075” of the tip. The blade is 0.015” thick at the break.

Would you guys consider that to be a materials defect that would warrant a replacement by Fallkniven, or is that an expected behavior of the steel?






cKc
Re: Extreme Lateral and Tip Strength
August 16, 2020 03:29AM
If your numbers are right that's like prying with a 5dps edge. Not abuse no. Clearly it has a thin tip. Not every knife is designed to do that. Especially in dead hard wood. My opinion is if you were really in survival mode you protect the knife rather than doing stuff like that. Warranty won't help you survive. Do it 100 times might still fail next time from fatigue

The knife has to go deep enough that the tip isn't taking the load which would make deep cracks and splits

At least it's minor

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It's not Cliff, its Dr Stamp
#kebabstickcut, it's a thing - make it happen
Re: Extreme Lateral and Tip Strength
August 16, 2020 03:52AM
Ok, I think that all seems pretty reasonable to me, cKc.

I’m actually somewhat relieved now because I can simply re-shape the tip by grinding down the spine to meet it, and now the tip has the exact geometry required for some of the most demanding things I could conceivably do with the knife.

It’s a good example of what you, Cliff, and other guys have argued for with regards to geometry: “Use it until it fails, then adjust the geometry just up to the point of no failure.”
cKc
Re: Extreme Lateral and Tip Strength
August 16, 2020 06:33AM
Yeah. You will also have a more central point which is better for drilling work. A tip on a scandi 12dps knife is a very robust tip because it gets thick fast but still has a needle point

I think a good test is to put a tip into a vice or pliers and very carefully test it's flex and work out how optimistic you should be for prying

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It's not Cliff, its Dr Stamp
#kebabstickcut, it's a thing - make it happen
Re: Extreme Lateral and Tip Strength
August 17, 2020 02:26AM
Fixed it:







I think it came out rather nicely. A Norton India coarse did the shaping, and a Naniwa SuperStone 400 did the finishing.

I really wish I had tested penetration through a phone book on a hard stab and a 50lb. push, that way I could get a sense for exactly how much penetration was sacrificed for the increase in durability. Aside from that, though, it’s back in action.
cKc
Re: Extreme Lateral and Tip Strength
August 17, 2020 04:12PM
looks good to me

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It's not Cliff, its Dr Stamp
#kebabstickcut, it's a thing - make it happen
Re: Extreme Lateral and Tip Strength
August 17, 2020 05:10PM
As an aside, they probably would have replaced it, but that behavior seems what you would expect from a high carbide stainless steel; very light plastic deformation and then fracture.

Nice repair job.
Re: Extreme Lateral and Tip Strength
August 17, 2020 06:22PM
Quote
CliffStamp
As an aside, they probably would have replaced it...

I remembered that you had gotten a replacement when the H1 broke on similar work and I was contemplating getting ahold of them. But then, like cKc pointed out, I thought about just how thin that cross section was and it seemed reasonable that it broke in that work. Plus I was really not looking forward to dealing with warranty-related shipping and emails in the current situation with the virus and all that.


Quote
CliffStamp
but that behavior seems what you would expect from a high carbide stainless steel; very light plastic deformation and then fracture.

This is really what I was hoping to hear. The heat treatment is probably fairly good then, and my ability to get it quite sharp with no burr removal or other special techniques also indicates that it’s decent enough.

Gotta hand it to the crew over in Japan, I’ve yet to see a single knife from that country with signs of a blown HT or the knife being burnt while grinding.

And for the record I knew it was very likely to break if I continued using it after I saw the slight bend, I just figured it’d be interesting to see what would happen anyway.


Quote
CliffStamp
Nice repair job.

Quote
cKc
looks good to me

Thanks, fellas. It’s not something I’ve done very often but I decided to just not overthink it and tried not to be a spaz about it. It worked out well enough.

Side note, the ability of the Naniwa 400 to very quickly remove even really large burrs is pretty astonishing. It’s just such a useful stone.




I took the day off work and have no plans at all, so I’l very likely make the video on it today and upload it later tonight as well.
Re: Extreme Lateral and Tip Strength
August 17, 2020 07:02PM
Quote
Ryan Nafe

Side note, the ability of the Naniwa 400 to very quickly remove even really large burrs is pretty astonishing. It’s just such a useful stone.

If you break sharpening apart into two steps :

-setting the edge
-setting the apex

It opens up a lot more possibilities with stones.
Re: Extreme Lateral and Tip Strength
August 18, 2020 12:25AM
I made the video and I’ll upload it to Bitchute later on, but during the video I forgot to make mention of a knife that’s very different in geometry but very similar in overall cutting ability, which is my Spyderco Chaparral FRN.

That knife has 2mm stock with a full flat grind of only 1.5 or 2 DPS down to a traditional secondary bevel. The edge profile is currently like this:

- 0.025” thick at the relief bevel of 10 or 12 DPS

- A small edge bevel of 0.008” thick at 15 DPS

- Microbevel of 20 DPS


When doing a slice into a 7/16” hardwood dowel, the knives make cuts to a similar depth when forces applied are high for both knives, and when forces are low for both knives then the Fallkniven pulls ahead. So even though the Spyderco has a dramatically thinner profile when looking at the stock thickness, grind height, and grind angle, the Fallkniven is still able to match or beat it on most materials because of the very thin edge.
Re: Extreme Lateral and Tip Strength
August 19, 2020 02:36AM
[www.bitchute.com]

Here’s the video.
Re: Extreme Lateral and Tip Strength
November 06, 2020 07:07PM
My uncle will be using the Fallkniven S1 for field dressing deer this year. I can’t actually remember which stone I finished the edge with, it’s either the medium or fine Spyderco ceramic.

All I know is that when I gave it to him it was as sharp as it’s ever been, it was push cutting receipt paper at a 90 about 1.5” from the point of hold along the entire edge and of course was shaving fine and soft hair with so little resistance and irritation that I couldn’t actually feel it shaving, it was simply sweeping off hair. I’m curious about how he’ll like using it. Opening weekend is on the 20th, two weeks away.
Re: Extreme Lateral and Tip Strength
November 29, 2020 05:18PM
The S1 now belongs to my uncle. I had nearly forgotten about his 50th birthday and since I had already loaned him the knife to try out for deer processing, I told him it’s now his. He didn’t shoot anything this year so it didn’t get tested, but I’ll post any updates on it’s performance here if/when he uses it for stuff.
Re: Extreme Lateral and Tip Strength
November 30, 2020 03:55AM
Considering the original question about a 6” super strong prying point with still some slicing ability, why did you not mention the Cold Steel Tanto? It seems right up the alley of what you are considering... With its hollow grind it is actually a fair cutter. I would recommend a San Mai Tanto, as the core is VG-1 not VG-10, and is outstanding. I found the Oyabun Tanto (7.5”-9”) to be thinner edge and sharper (but also thinner stock and not SAN Mai)

An old San Mai Tanto is easy to find at a low price, and has excellent leather sheaths, way better than just a scratchy plastic sheath... It is also very compact, and you will never see the edge chip...

The reason why the Fallknivens chip despite “strong” edges is that the curvature of the convex focuses lateral stresses on the apex, as I’ve pointed out in another thread happens also with thin Full Flat Grinds: The hollow grind protects the edge more because the hollow makes the edge’s v shoulders sharper for the same angle: Sharper shoulders take lateral loads away from the apex itself. It seems little but it does make a difference.

I don’t like Tantos because the profile is on the narrow side. But there are tons of dull pointed 6” knives out there... Another that comes to mind is the SOG with a flared tip shape whose name escapes me: That has a broad blade... (Edit SOG Creed is what it’s called)

G.

PS: Not the least of the Creed and Tanto’s attraction is they avoid the weight of those horrible full profile tangs... The stainless is also excellent whenever made in Japan, but the Creed might be Taiwan. Japan is worth the extra price no matter how high, or if you have to get a used older model on EBay at an inflated price... I never found anything wrong with Seki made stainless...



Edited 2 time(s). Last edit at 11/30/2020 04:17AM by Gaston444.
Re: Extreme Lateral and Tip Strength
November 30, 2020 07:29AM
I can’t do it, fellas. It just ain’t in me to do it anymore.
Re: Extreme Lateral and Tip Strength
January 10, 2021 06:21AM
I would really prefer if Fallkniven/Hattori put these same knives out, but instead of laminate VG-10, they used one solid piece of something like 12c27m at near-full martensite percentage. The knives would just be so much better at the heavy work. Especially the large ones like the A2, A1, NL3, NL2, NL1, etc. They’d be cheaper to make and buy and they’d be much better for chopping.

I really want one of the medium or large sized blades (especially the NL3 or the NL2) but I just can’t do it because I have no desire for a chopping/prying/digging tool that’s made from high-carbide stainless. As a pure cutting tool, then the high-carbide stainless is fine or even optimal for a lot of work. But for primarily doing wood carving, chopping, and potentially seeing lots of impacts into the ground, I just can’t go for that steel type. It’s really a shame that they don’t offer at least the larger knives in a simple stainless with a solid heat treatment.
cKc
Re: Extreme Lateral and Tip Strength
January 18, 2021 10:16AM
I think something like the BUSSE TEAM GEMINI ULTRA LIGHT BRIGADE with a thinned down edge would be a good alternative. price is around $450 direct.
or some other similar looking knife with a reasonable blade steel.

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It's not Cliff, its Dr Stamp
#kebabstickcut, it's a thing - make it happen
Eee
Re: Extreme Lateral and Tip Strength
January 22, 2021 04:51PM
Quote
Ryan Nafe
I would really prefer if Fallkniven/Hattori put these same knives out, but instead of laminate VG-10, they used one solid piece of something like 12c27m at near-full martensite percentage. The knives would just be so much better at the heavy work. Especially the large ones like the A2, A1, NL3, NL2, NL1, etc. They’d be cheaper to make and buy and they’d be much better for chopping.

I really want one of the medium or large sized blades (especially the NL3 or the NL2) but I just can’t do it because I have no desire for a chopping/prying/digging tool that’s made from high-carbide stainless. As a pure cutting tool, then the high-carbide stainless is fine or even optimal for a lot of work. But for primarily doing wood carving, chopping, and potentially seeing lots of impacts into the ground, I just can’t go for that steel type. It’s really a shame that they don’t offer at least the larger knives in a simple stainless with a solid heat treatment.

I would seriously consider buying something like you suggest. Other options I’ve considered are the Terävä Jääkäripuukko (can you tell I had to paste that in so I could spell it) and the Buck Nighthawk.

[www.varusteleka.com]

Both are possibly not the grind you’d want, but I’ve used Leukus with that higher sabre grind with micro bevel and they are very effective.