Cheap Knives: Why The 440A Craze?

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Gaston444 said:
Airplane bolts that connect the engine to the wing are $2-3000, EACH, and may go much higher for some of those on the spars, which can go upwards of 6 inches in diameter or more.

Just to show those who claim there are no such things as bolts costing in the thousands...

Even better are the fan blades: The most expensive ones are apparently for the Airbus 380, made of Titanium, and they are $ 160 000 for a single blade of about 6.2 ft. in length by 20 inches at their widest...

As to judging my rate of progress on wood you haven't seen, I'm really impressed by your skills. Sincerely. Lots of experience on display in this comment.

This particular GSO-10 is 21 ounces, with a blade 1/4" wider than the Master Cutlery knife, and a much heavier spear shaped drop point that it is almost impossible to get to stick in wood. This is actually a bad feature, because it means it is easier to lay the knife down on the ground where the edge will more likely get damaged. It won't hold still for hands free cutting either... The Master Cutlery is sharply pointed and 16 ounces, with a Full Flat Grind and a slightly thicker edge: Basic physics would say it should be far behind, yet it did about 70% as well. It definitely matches or beat the CS Trailmaster...

There is no anti CPM agenda: People here don't chop wood with their folders, which is why they don't see the apex structure can't take that particular use.

Flex test?! Apparently cutting has something to do with flexing a 3/16"-1/4" slab of steel. Let's keep that precious information in mind...

Gaston
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Uhhhhh... Thanks for the insight on airplane bolts and fan blades even though that has nothing to do with my comment.
Here’s another useless fact. It is physically impossible to lick your own elbow.

Next time you stab the knife into something, go with the grain. You could also use the sheath that is supplied with the knife. Crazy idea right?

As far as flexibility goes, it is important for most of us who use a knife while carving, splitting, prying, etc.
I’ve had a handful of 4”+ knives in both 440c and AUS 8 that failed under flexing while similar high carbon knives or “super” steels didn’t.
 
Thomas Linton said:
I have not read all this thread, nor do I wish to do so. When I try, it's hard to figure out what is going on.

People have been chopping with khukuris for a good bit of time. They are generally made of steel closer to that used for axes - low alloy, lower carbon that most knives, like 5160.

I have some more "modern" steels in knives, but I elect not to chop with them, saving that for tools optimized to chop by design, construction, and material.

Oh well.
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Far too sensible for this thread. ;)

Not just the Kuk, but of course the Machete and Parang, to name another two. But as you eloquently pointed out, the material and structure is crucial. Whether a felling axe or a splitting axe, both rely on the steel, HT and geometry, including the geometry of the edge itself.

Another really great tool for those “I need to cut through this large seasoned log because for some unknown reason my life depends on it” moments, is the humble saw.
 
Gaston444 said:
How about this: To be considered "Aircraft Quality", all aircraft metal components must be analysed for purity of content. Impurities are a well-known production issue that affects the durability of the material.

Sorry to break it to you, but the metal in every one of your knives would not be acceptable for aircraft manufacturing because the manufacturing process is not checked for impurities: It is not aircraft-grade. Because knives are low-tech items, they are not a life or death matter for hundreds of passengers...

Does impurities in the metal affect edge performance? It obviously does, but since the parameters for verifying this fall outside the requirements of this particular industry (especially the custom knife industry, which is an even lower-tech small output variant of the mainstream knife industry), there is no way of really knowing "where" a particular knife or maker falls in a "Cleanliness spectrum" that is clearly outside the realm of this low-tech industry.

Ever wonder why some airplane bolts cost thousands of dollars each? You think a few of those made to the quality level of your knives would pass muster to hold an engine up?

There are a few clues that steel cleanliness is a significant issue: Among those, from what I observed, is that the worst edge performance I have ever seen was usually from expensive, small run US custom makers. Among the best I have ever seen was usually Aus-6 production knives from Seki City (in Al Mar knives notably), but I have even seen recently a low end 420 produce similar performance (From cheapo Master Cutlery no less!): These are not even high carbon stainless, but they are all from high volume factories... I did read that Japanese steel makers made special efforts to have the cleanest and finest grain steel possible, and I did see the superior results of this even on medium range Seki made knives. From whatever maker, I will gladly pay a huge premium to see "Seki", or even just "Japan", stamped on any knife... Only once, with an oddball low-end company called "Oryx", did the "Japan" stamp fail me.

The very first time I was ever made aware of this steel "cleanliness" issue was in a mid-80s yearly "Book of Knives" issue, one of those yearly soft cover books with a huge list of custom makers, where a sizeable article was devoted to single 19th century straight razor that had demonstrated an exceptional ability to hold an edge through an incredible amount of shaving, and this over a very long period of use. The author had an extensive spectrograph analysis done on this old razor, to see if anything was special about it. It turns out there was nothing special about it, except that the steel was so incredibly clean...

I remember a specific sentence in the article, which stayed with me ever since: "If only aircraft-quality aluminium was this clean!"

Just because something is outside the reach of a particular industry does not mean it does not exist. That big runs of cheap high volume steels could have a higher inherent performance than small runs of expensive low-output makers may seem counter-intuitive, but it is certainly not outside the realm of common sense.

Gaston
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Gaston what are you going to do if someone takes a video of themselves chopping wood with s30v and their edge doesn't self destruct?
 
Pilsner said:
Aha! But those ‘so-called videos’ don’t reveal the clogged edges. And the DPS is probably something crazy like 25 degrees. Hell, I’d imagine those fools might even favour convex geometry.
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Yep.
They’re fools because they don’t need to change the bevel geometry to overcome their inability to put force behind a knife while swinging it.
 
Gaston444 said:
If I rubbed my nail along their CPM steel choppers, after they chopped at or under 20 dps, you would see on their knives the exact same thing you see in my pictures.

Gaston
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Gaston, you aren't the only human here that has a thumbnail.
You may think that's the case, but it is not.

Heck, even I possess a thumbnail...on both thumbs!
And yes, I have used them to check the edges of knives; you have not come up with some amazing new knife-testing technique that revolutionizes the knife world.
Sorry, but you have not.
 
danbot said:
Why would you use 20 dps or less for a chopper? I would go with at least 25dps and ideally a convex edge. You need the most steel possible behind that edge to support it! Especially for chopping at hardwood.

You need to make your testing realistic. I could baton my straight razor into a piece of seasoned oak and then say it sucks at edge retention, but is that at all a realistic test of a shaving edge?
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It is realistic, on "normal" dried wood like Maple, if other low carbon steels like Aus-6 can take 15 dps without damage...

15 dps is still a pretty stout 30 degree wedge...

Good 440C will routinely take no immediate micro-folding even at 15 dps, but after 50-100 strikes it will start to happen gradually (the rarer exception to this being my Lile's D-2, but this can occasionally chip): To counter this I have now settled on a 15 dps edge with a 20-22 dps micro-bevel for a good chopping edge: This I consider ideal, but strictly for chopping: A pure slicer would of course be 12 to 15 dps with no micro-bevel.

But a 20 dps micro-bevel is still good 440C steel not micro-folding with a 15 dps main edge, not 20...

And even when it did micro-fold, it was after 50-100 strikes, while all the CPM steel I have seen folded from 20 dps, or more, in typically less than 10 hits... Anything CPM below 20 dps folded visibly in ONE hit... On dried Maple...

And there is no "test" error, beyond accidentally twisting the blade too harshly on retrieval: The beauty of checking for micro-folds with the nail is that it is an entirely binary test: The apex either folds, or it doesn't.

The only reason you would even think of a 25 dps main edge bevel as useable for chopping is probably because you are using gloves: Even at 20 dps the deceleration is quite unpleasant, performance low, the sound changing, and at 25 dps all you hear is "pat-pat", like hitting with a metal stick... The log then has to be super secure to not move all over the place... Factory edges are laughable, and this is why some pro re-grinders are now a two months wait...

Knives require finesse to really chop well: A 0.020" edge base is ideal (while what you typically find, as on the GSO-10, is over twice that), and is what Randall uses on their biggest knives. Knives do not chop the way axes do.

Gaston
 
Standard78 said:
Baseless crushing?
It looks like the GSO 10 came out ahead in this ridiculous comparison.
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It looks to me like you have trouble differentiating a claim about steel and edge damage, and the performance of two different knife designs...

Should have picked this up earlier, but absurd thoughts have trouble entering my mind you know?

Gaston
 
I am sure this has been answered sufficiently in this thread, but I will put my two cents as someone who has owned countless stainless steel knives over the last 25-30 years at least half of which have been 440a/b or AUS6/8. These steels are cheap and easily available. Their biggest advantage is very high toughness for a stainless steel at good enough edge holding. I don't care what the paper stats say, but in my experience 440a/b has been much tougher than S30V. By a large margin. At the expense of edge holding. This has been through the use of many, many , many knives. Not just one or two. And it held a better edge than any of my 420 blades.
 
Have you tried a convex edge sharpened to approx. 60 degrees inclusive with a knife that has sufficient weight for chopping wood?
 
stabman said:
Gaston, you aren't the only human here that has a thumbnail.
You may think that's the case, but it is not.

Heck, even I possess a thumbnail...on both thumbs!
And yes, I have used them to check the edges of knives; you have not come up with some amazing new knife-testing technique that revolutionizes the knife world.
Sorry, but you have not.
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And if you had read my posts, you would know I said I learned it here in this forum...

L3F91np.jpg


S30V after slicing 1/8" cardboard once or twice.

mIeHe6j.jpg


GSO-10 after 10 strokes on Maple.

hUzEHdi.jpg


CPM 154 after 10 strokes on Maple.

mUdV6cN.jpg


S30V after less than 10 strokes on Maple, separate hit area forward < 3 hits.

I've posted now 4 different knives in 3 different CPM steels, ranging from $300 to $1700 in price, and all displayed significant micro-folding far faster than any other steel I have ever tried, really almost from single contacts with wood in some cases... Just astounding stuff.

If you think I wanted to see the $1700 knife do this, you have a peculiar logic...: I hand sharpened that thing, hoping for nearly two years to finally get into the promised land of the "unburned" layer... Alas, there is no promised land, when the word printed on it is S30V...

And yet by sheer amazing coincidence, in this fool-proof ultra-simple binary evaluation, I am almost the only one who got all of the bad CPM knife steel in the past twenty years (except for a few really embarrassing on-camera total failures of course, JDavis882 etc: Chhht!)...

That just sounds terribly likely... By an amazing coincidence, everyone else's CPM steel is just absolutely resistant to micro-folding after chopping ten times into the average dried wood, from a big 9-10" blade at around 20 dps. Heck, everyone's GSO-10, with factory edge, never displayed this instant micro-folding in years and years of chopping. Everything is just peachy rosy for everyone else except me...

You know, I'm totally buying stocks into that.

Since I posted four pictures of what I am talking about, why not post some post-chopping pictures demonstrating your amazing good fortune? What can I do?: Not being there I can't (and won't) call you a liar, but I would really be curious to see all that amazing CPM steel working flawlessly up close. It would be an amazing sight to my sore eyes... Like seeing a part of another world, you know?

Gaston
 
danbot said:
Have you tried a convex edge sharpened to approx. 60 degrees inclusive with a knife that has sufficient weight for chopping wood?
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Is the GSO-10's 21 ounces not heavy enough? My $1700 custom knife above, in S30V, was 10.5" and 25 ounces.

As to using a 60 degree inclusive convex edge, I think chopping with a flat spine would be less painful... This is axe territory, not a knife edge...

I just tested a well under 30 degrees inclusive convex edge on a knife of 25 ounces, the Busse Battlesaw, and I thought it was still a bit "harsh" decelerating compared to my thinner 0.020" REK V-edge Voorhis... The Busse had an almost too thin apex angle, yet the "swelling" still decelerated it abruptly...: V-edges are less harsh on a narrow 0.020" base

The convex REK put on it really must have been around 12 dps at the apex: INFI still passed without folding...

INFI at thin angles has an interesting way of doing very tiny micro-"rippling", with no folding at all: It could be the convex profile is contributing to this, but keep in mind it did not fold at something that is well below 15 dps at the apex itself...

Gaston
 
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