SAK's steel performance

[Son of Triglav]

Hello!
I've got puzzled by something.Some time ago, I did a little experiment. I was interested in actual SAK's steel egde holding so I used a swiss army knife (soldier model) to cut (carve woud be a better word) throught an axe's (small sized) wooden handle .The wooden handle was pretty hard wood,cros-section measuring approx. 3/4"×1 1/2" .The SAK's blade was hair shaving (I used fine ceramic stone to sharpen it befor experiment). Wooden handle was cut from all sides towards center (as when chopping a tree) until the handle came appart.I almost mainly used the lower part of blade to make short ,(mostly) push-cuts It took me 40 or 45 minutes or so including some 9 (or so) min pause.I didn't count cuts I had made ,but it must had been hundreds of them.While I was cutting I was checking sharpness of SAK's blade and what really surprised me was that the edge just didn't want to get dulled ;as at the beggining -it was after some 15 or so minutes of cutting stll shaving sharp, no dicernible(at least not to me) difference in sharpness from the moment I start cutting.I was rather surpised.I kept on cutting, later the blade became somewhat less sharp,but it could still shave hair(but not so smoothly ,easily as at the begining) from my arm.I was very surprised by this.I thought was that some kind of (supra-natural) phenomenon
going on? It seemed to me that the blade just didn't want to lose its sharpness. I continued cutting until I separated the wooden handle in two pieces.Guess what? After that many push-cuts,the egde was still unusualy(after that many work) sharp- scraping shaving sharp,and it could still shave(scraping) hair.It's needless to say I was pretty amazed.Now, people here (at bladeforums) said SAKs steel is supposed to be of low quality steel, "el cheapo" steel,sort of the lowest steel etc.Ofcourse I too hadn't expected much from its steel (because of SAK's relatively low price). Obviously it's not that low quality steel after all. Has anyone got any explanation regarding this ? I'm interested to hear any explanation,comment from other forumites?

 

[Buzzbait]

Congratualtions. You just discovered steel snobbery. I feel the same way about Camillus' and Buck's much maligned 420HC. No, it won't stay sharp over a year of hard use, but it will stay sharp throughout a major project. For most things I do and places I go, that's good enough for me.

There are much better steels than 420HC or what is used on a SAK, but the differences only show up under prolonged use and lack of maintenance. I do have a few knives that require a stronger steel, but most of my small folders are perfectly happy with what many consider to be "lower grades of steel".

Enjoy your SAK, and rest knowing that it'll come through a tough pinch without a problem.

 

[knifenerd]

IMHO, Buzzbait's comments are very well placed. I've used a variety of SAK's for more years than I care to remember, and the blades have stood up quite well.

I also have an old Buck 110 that has experienced everything but a nuclear strike and is still serviceable.

Keep in mind, I am not trying to rip open the tops of 55 gal. drums with these knives. Just normal, intended uses.

 

[Danbo]

Personally, I love SAKs. For the money, it is hard to beat them. As for the results of your cutting tests, I think a lot has to do with the very thin flat grind of the blade. The steel they use is something like 440A, but it sharpens nicely.

 

[Blues]

I too am fond of my few SAK's. Always have one in a kit in the car, or on my belt in the woods (along with a fixed blade, of course.)

As to the edge holding when working wood, it reminds me of something Kit Carson said to me a few years back..."Steel hard, Wood soft."
(You get the idea, especially if you know the big hillbilly. )

 

[Cliff Stamp]

Son of Triglav :

Obviously it's not that low quality steel after all.

Those are relative terms, compared to the high end steels it is of low quality. Compared to a cheap kitchen knife, it is of high quality.

Has anyone got any explanation regarding this ?

You were cutting a material which doesn't have the ability to abrade the edge, thus blunting will set in by deformation. The extent of blunting will therefore be controlled by how hard you are cutting with the blade. If you vary the side used to balance out the deformation, this will minimize the edge rolling and cause the rate of blunting to be very low.

Blunting is also an exponential decay. This means that the time (or amount of work) it takes to blunt a knife gets progressively longer as the knife gets blunted. For example the following shows how two knives (ATS-34 custom, circles; 15n20 custom, plus signs), react to cutting wood :

http://www.physics.mun.ca/~sstamp/images/ss_rd_edge_percent.gif

The ATS-34 blade resists the edge deformation stronger and after ~100 cuts shows no loss of sharpness. The 15n20 blade has degrades slightly, which you would expect given that it is softer and of a low carbon and alloy content. After more work is done the ATS-34 blade eventually starts to degrade, but the performance stays ahead of the 15n20 blade (~35%).

That graph is from the review of the Running Dog Traditional Tanto :

http://www.physics.mun.ca/~sstamp/knives/running_dog_tanto.html

About 65 +/-5 lbs of drive was used in the wood cutting. Note, the rate of blunting is *highly* dependent on the force used as well as the speed of the cuts.

Do Swiss Army knives blunt the minute you cut something with them? No. Do they last alongside higher quality cutlery? No. From a per cost basis they certainly do however. And as Danbo noted their cutting ability is very high.

-Cliff

 

[Jerry Hossom]

Originally posted by Buzzbait
Congratualtions. You just discovered steel snobbery.

Since I use high performance steels in my knives, the most frequent complaint I hear is how tough they are to sharpen when they finally need to be. With a properly shaped and finished edge, even modest steel can cut well and long. I have re-edged a number of Ontario Machetes, using a wide convex edge shape, and have used one to cut down a lot of sapplings after which it still shaved. I demonstrated this to some other knifemakers visiting here during the Blade Show, and my last poor machete went home with one of them.

As for..."Steel hard, Wood soft." The only CPM-3V edge I've ever had roll on me, including incidental hard contact with the spine of an Rc61 ATS-34 blade, was when a customer chopped up (completely) a very old oak office chair. Axe handles are often Hickory, and if you've ever tried to cut hickory, even when green and using a chain saw, you know it is not anybody's definition of "soft".

 

[Blues]

I agree Jerry, having done my share of chopping hard woods and felling trees in northern NY.

My assumption was that he was whittling the handle, which wouldn't have quite the impact on the edge that chopping would.

Never did quite get the hang of using my SAK's as choppers.

 

[James Y]

Even though I own several knives I love in higher-end steels (ATS-34, CPM-440V, 154-CM, etc.), I still love the SAK (in particular, Victorinox). And I do agree about the steel snobbery. In the past people made do with steels in their pocketknives that probably can't come close to the SAK steel today, yet got great use and accomplished some amazing things with them. As well, the SAKs are very easy to resharpen when needed and are extremely rust-resistant. Some may say due to low carbon content, but SAK seems to have it right for their product.
Jim

 

[muzzleup]

The reason I switched to the Victorinox RS multi tool is because the knife steel is soooo much better the the knife blades in my Leatherman tools.

If the steel in the SAK is a low grade steel then I guess I like their low grade steel because they do just what they were built to do! and do it well.

 

[Son of Triglav]

Thanks all, for your replies and comments. I too agree with Buzzbait (and others with the similar view regarding certain underrated steels ) regarding steel snobery.

Danbo :

As for the results of your cutting tests, I think a lot has to do with the very thin flat grind of the blade.

Maybe ,but wouldn't a thin edge (common reasoning) be the cause for blade dulling faster than one with a thicker edge?


Cliff wrote:

You were cutting a material which doesn't have the ability to abrade the edge, thus blunting will set in by deformation.

A thought like that(low abrasion of that wood) , came across my mind .But how do you really know it's true ,I mean, which type of wood has got low/high abrasive characteristics?


Blues, yes, I was whittling the handle (actually never tried to chop with a SAK ). Nevertheless the wood was hard (if you hit someones head with such handle it would hurt like hell) , so I had to use some force,not very great.,however it was more than regular.I awaited(expected) to edge sustain some damage ,but it didn't.

 

[dragon2]

This reminds me of Ed Fowler's test for handle comfort. He suggests whittling an old railroad tie in two. While I'm on the subject, did the SAK handle hurt your hand during this experiment?

 

[Jeff Clark]

I think that this was a very good test due to using an axe handle as the test material. This is typically a very tough wood. I would guess something like ash or hickory. The thinnes of the SAK blade would influence the type of cuts made during the process and the effort to make the cuts. I don't think it materially affected the wear on the edge. The SAK alloy must have been reasonably tough to stand up to this test. It is surprising when you consider the somewhat low RC value of the blade (around 56 I believe).

If you wanted to try another test with a somewhat dirty medium (more abrasive) where you can feel the effects of wear...try cardboard boxes. If you get a big pile of one type of carton and start cutting them into 2cm wide strips, you can count the total length of cut till the blade gets "dull". This is also a real world test since a lot of cardboard boxes get opened with SAK's.

 

[Falcenberg]

Just one year or two ago, in their site

www.victorinox.ch

Victorinox said some informations about the alloys they used for the different blades of their tools.

Now you can download an "almost" exaustive brochure from the same site, going to "Portrait" Section, "Facts" subsection, clicking "media informations" and then "Download", to get a .PDF document saying infos about alloy, RC hardness and coating of different blades.

I own a SwissChamp since 1980, and it is still efficient, also after some hard use and abuse. All blades are OK, and no blade play.

Falcenberg

 

[Jerry Hossom]

Cardboard = Wood Fibers. I'm not sure how one can be judged more abrasive than the other. Since cardboard is usually made from pine or recycled paper (also pine), I would expect it to be somewhat less abrasive than a hardwood fiber like hickory or ash. There is also wide variability in the fiber content (recycled versus new versus type of pine used) as well as construction in cardboard so I'm not sure it's a very reliable standard for any external comparisons.

Frankly I'm impressed with the knife's performance.

 

[David Rock]

It's my understanding that cardboard contains more than just wood fibers. It has abrasive stuff in it too. Cutting cardboard dulls knives faster than shaving pine, in my experience, just like sharpening pencils dulls knives faster than whittling weenie sticks.

David Rock

 

[Cliff Stamp]

There are a number of reasons why cardboard is a stronger dulling medium than wood. First off off when cutting wood you generally cut with the grain, this causes a very smooth cut and a lot of splitting of the wood which really reduces the beating the knife edge takes. When you cut through cardboard the wood particles are all orientated in a random manner and just smash into the edge. What is even worse is that the binder is not strong enough to hold them in place so instead of being cleanly cut they just rip and tear. There is a huge difference between a smooth cut and a break in what it does to a knife edge, the latter is a *huge* level above in regards to wearing/distorting a knife edge.

As well you have to consider other effects like speed of cut. When cutting woods, especially hardwoods you are cutting very slowly. You can zip through cardboard at easily 10 times the speed you can cut through wood. This means the impact energies will be 100 times greater. It also means that the edge will heat up significantly. After a few fast rips through carboard a knife edge can become that hot that it will generate a first degree burn on skin. Note as well that the metal will conduct heat rapidly throughout its body so the edge was much hotter than when you touch it. Excessive heat lowers the strength and wear resistance of knife steels, some more than others.

Cardbords as well contains other things besides wood pulp or compressed paper, it also can contain a glue or paste, and it not as "clean" as fresh wood.

I gave up on wood as blunting stock quite some time ago as you have to do thousands of cuts to dull a blade, unless you use extreme force, and the latter just rolls the edge anyway, and because of the fatigue generates takes forever to cause any significant wear. If you do want to use it, cut across the grain of the wood as fast as possible and reverse the knife edge so you are hitting it from both sides.

Son of Triglav :

I thought like that(low abrasion of that wood) , came across my mind .But how do you really know it's true

You can tell if an edge has rolled by touch, it will be much more aggressive on one side than the other. It will also respond very well to an alignement technique like steeling. If a significant amount of material has worn away, most steels also tend to fracture so you can also check the edge under a magnification. Some of the really hard woods (ironwoods) are very difficult to cut and probably abrasive, however they are not good to use as blunting stock because of cost, unless of course they are natually found on your land.



-Cliff

 

[allenC]

Maybe you could use old carpet.

 

[Son of Triglav]

dragon2:

While I'm on the subject, did the SAK handle hurt your hand during this experiment?

No, I can't remember SAK's handle war hurting my hand, at least I didn’t notice it.


Regarding abrasion wood vs. cardboard, so far I haven’t noticed that cutting a cardboard dulls a knife faster that cutting a wood. I don’t think that a cardborad is more abrasive medium than wood,especially hard,dense one,like that axe handle,which was not easy to cut into at all,while it’s very easy to cut through most cardboards.


Cliff :

First off off when cutting wood you generally cut with the grain, this causes a very smooth cut and a lot of splitting of the wood which really reduces the beating the knife edge takes.

I looked at that former axe handle grain, and the grain goes diagonaly across the cross-section. That means I was cutting as much with the grain as against the grain. And there was no splitting ,the knife,the egde had to pushed through whole lenght of a cut.

Since heating up the blade was mentioned. After I had stopped whittling I noticed that the blade was quite warm, heated up. Although I can’t exactly say if it was significantly warmer than a handle which is made of aluminium.

Anyway, the test made big impression on me. A knife(steel) that’s capable of cutting that much hard wood and still shaving is just as good for me(if not more- because of easy sharpening and low costs) as any knife made from high tech steels famous for their edge holding.


Btw if someone wants to try most(?) dulling medium, I suggest cutting tomatos,that’s tomato skin. Some two weeks ago I sliced a tomato with a Randall 14. Before cutting a tomato, it could shave hair from my arm. Hard to believe but it was duller with every slice I made and it became quite dull with the fifth or so slice. Not only it could not shave hair in any way whatsoever, the edge really felt dull. Fvck. I didn’t even try to cut further.:barf:
Now, I know that tomatos skin is very dulling(for some unknown reason to me) on knife's edge,but that was just too much disapointing.
Does anybody know true hardness of Randall blades? What’s with their heat treatment? It seems (at least the one I own) they’re incredibly soft (I’ve noticed this before),definetely in low 50’s.

 

[The General]

I used my Vtnox Adventurer a little while ago to cut away a 1.5 foot high hard rubber plant pot. This was so I could take the plant out without having to pull and damage the roots.

The knife went amazingly dull from this, it would no longer cut paper. If a ATS-34 blade had done this it would have gone in the bin. I also used it camping a while ago to make some fuzz sticks. It went noticably dull in sections after only 20 mins of this. Like 420HC this is not a great steel, but it will do in an emergency. Just don't get over exited about it...