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Testing Methods
- Thread starter RedWing
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I lock about and inch of the tip in the vise and test it's breaking point/strength then I look at the grain. Slicing a free hanging rope in one cut is an excellent sharpness test. Whacking through a 2x4 a couple times and then seeing if it still shaves hair is a good edge holding test. Dropping the knife tip first from shoulder height on concrete is one I do sometimes but, I wonder, does anyone else do this?
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It's to test how good the HT is and if the tip can take getting stabbed into something hard or accidentally dropped. I got this testing method from no other than Wayne Goddard although I can't say it's the most valid test, it can tell you how your blade will perform in that area.
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ron_m80
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I remember hearing about all the thurough knife tests people conducted on their randall's. (i think it might have been in a military book or something). So when i got mine, I pulled it out of the sheath, and rubbed the oil off it checked the feel, the finish, and everything, worked the leather sheath a bit to loosen it from the blade(it was a very tight fit at first, though not in a bad way)
And then I decided to find out if my time and money were well spent, anyone that has waited for one knows how long it is.
So i went outside, found me a nice old and i mean old redwood 2x4, layed it out sideways, and plunged the tip into it, I think i got it about 3/4" into it. and quickly and forcefully pryed it over to its side......
well the result was, flawless perfectly gouged large chunck or redwood lifted from the grain. I realized then how stupid knife tests were. what if it had broken? what would i do for a blade then?
My point, thank you for tolerating the story, is that with the internet, people that share their experiences on websites like this and such, make frivilous knife tests a thing of the past, that is of course unless you are dead set on proving any or some of us wrong. Knife names exsist for a reason, I would trust a busse right there neck and neck with my randall (might not love it as much), but based on what i have learned here why would i risk damaging an otherwise good blade with some asenine test, someone else has done already?
Use the damn knife, use the shit out of it. A lifetime of use is the true test of a blade. It kinda follows suit with the oposite of the idiotic "near-sighted" saying. "Life is short", the fuck it is, its the longest and hardest thing you are ever gonna do!!
EDIT:
And then I decided to find out if my time and money were well spent, anyone that has waited for one knows how long it is.
So i went outside, found me a nice old and i mean old redwood 2x4, layed it out sideways, and plunged the tip into it, I think i got it about 3/4" into it. and quickly and forcefully pryed it over to its side......
well the result was, flawless perfectly gouged large chunck or redwood lifted from the grain. I realized then how stupid knife tests were. what if it had broken? what would i do for a blade then?
My point, thank you for tolerating the story, is that with the internet, people that share their experiences on websites like this and such, make frivilous knife tests a thing of the past, that is of course unless you are dead set on proving any or some of us wrong. Knife names exsist for a reason, I would trust a busse right there neck and neck with my randall (might not love it as much), but based on what i have learned here why would i risk damaging an otherwise good blade with some asenine test, someone else has done already?
Use the damn knife, use the shit out of it. A lifetime of use is the true test of a blade. It kinda follows suit with the oposite of the idiotic "near-sighted" saying. "Life is short", the fuck it is, its the longest and hardest thing you are ever gonna do!!
EDIT:
I must confess to missing that part entirely, it makes for a whole other conversation.redwing said:
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Probably the only tests that I do on every blade is to test the hardness after H/T and test the sharpness after completion. Occasionally I will test one to destruction just to know the limits of the blade. This I will do with anything from a baby sledge, to a cheater pipe, or simply "whacking" different materials to see the edge damage (if any) that occurs. Obviously you can't to this to every blade but it's nice to know what to expect from your blades.
Gary
Gary
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Cutting cardboard will test edge holding well.
Mike
Mike
Thanks for the input guys. I've done most of the tests listed except for the free hanging rope cut since most of the blades I've made so far have been short (3 inch or less blade) hunters and utility knives.
I remember reading in one of the old Herter's guide books as a kid that he felt that knife should be able to cut a common nail without breaking or rolling the edge when pounding it through.
Joe
I remember reading in one of the old Herter's guide books as a kid that he felt that knife should be able to cut a common nail without breaking or rolling the edge when pounding it through.
Joe
I'm going to play devil's advocate for a second....
What specifically about the heat treatment does dropping a knife tip-first onto concrete prove? I don't believe that I've ever seen an industry-standard "concrete drop test" referred to on any steel industry materials information sheet.
I don't see the point in performing a test, and reviewing the results, unless you know specifically what properties you are testing for and why. Just because some magazine and knife industry luminary does something doesn't make it a good test. Now, if Mr. Goddard had sat down with you, and explained the "why" behind the test, what it was intended to prove, and what properties of a "good HT" this test showed, I might give it some weight. It's possible that he did and you've simply explained it poorly, I don't know. I'll admit it does bug me a bit when I hear "soandso told me that if I can walk the woods on a quest for an Ent, and chop down said Ent with my knife before he runs away then my blade must have a good HT" with no questioning as to the "why" of any of it, it simply proves that you don't question people that the knife industry have decided are "important".
Sorry for hijacking the thread, it's just that claims with no backing other than "because <insert name of hero here> said it" are one of the main reasons for misinformation in the custom knife industry. We all say that we expect educated consumers that will pay a premium for the quality we're putting into our knives instead of grabbing a WalMart special...We should give them something more valuable than snake oil and try to be at least as educated as we say we want them to be. Frankly, I'd take a $20 WalMart knife, that had some semblance of industry controls on it's HT over a knife from a 'smith that can't explain the reasons for how he determines quality.
Maybe it's just me. I've never worshiped my heroes, I've always worked hard to get to a point where I feel I can challenge them. I suppose I'm just weird...
-d
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I've done the concrete test several times, more on a lark than anything else
I always imagined it was somewhat of an impact strength test.
unfortunately the variable nature of the concrete renders the test somewhat moot. but it's kinda fun anyways
I always imagined it was somewhat of an impact strength test.
unfortunately the variable nature of the concrete renders the test somewhat moot. but it's kinda fun anyways
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I don't make too many fixed blades anymore but I've dropped an awful lot of them tip first on the concrete from chest height. With my folders sometimes I do the brass rod
or put severe bends in them. I EDC one of my toothpicks and if pipe needs reaming I use it, nothing like getting it all figured out by using it every day whatever that need may be.
deker- Wayne Goddard goes on to explain in that book exactly why he does that test.
Ken.
or put severe bends in them. I EDC one of my toothpicks and if pipe needs reaming I use it, nothing like getting it all figured out by using it every day whatever that need may be.
deker- Wayne Goddard goes on to explain in that book exactly why he does that test.
Ken.
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Personally I like the "critter" test. If a knife will still have a sharp (relatively) edge after field dressing and skinning an elk, it passes. At least that was the method I have used while fine tuning my heat treating and edge geometry over the years. I have given enough knives away to friends and gotten reports from customers and experienced my own tests that I know what works for me. There is nothing like thick hair and hide to test a knife.
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Deker, I guess it should come as no surprise that I couldn’t agree more. The reason I clicked on this thread is that it is one that pops up once every 2 weeks or so, and it is the same old suggestions made again and again. There is always the familiar lineup of tests offered, many from favorite authors or other sources, and most folks are tickled with the results of their blades from these tests… yet what did the test really tell them?
I am for all kinds of testing and I am not saying that the brass rod test, the file test, slicing, whittling, shaving, bending, flexing, whacking, whopping, torquing are necessarily bad tests. Any test is valid as long as we know exactly what it is telling us, and more importantly what it cannot tell us. If we don’t know what it is we are measuring the only real benefit of the test is the exercise our arms might get. Thus the file test is great if we are looking for abrasion resistance or scratch hardness, it is even better if we combine it with a Rockwell test and get an overall picture of hardness in both penetrative and scratch. If we combine this information with what we see in the brass rod test and keep close track of the edge size and geometry from knife to knife, then even that test starts giving specific information. Putting a knife in a vice and “flexing” it tells us one thing, “bending” it tells us another, it is not a measure of strength at all but an indication of ductility which is the opposite of strength. But if we don’t know that the test is not even all the great of a cardiovascular workout.
All that being said- I have used the point drop test myself, and for years performed it in my heat treat demos to reinforce the differences in marquenching and traditional quenching. Since nobody would dream of taking a cold blade straight from the quench with no temper and drop it 6 feet, point first onto concrete, I enjoy the gasps as the point impacts with no damage. This is a backyard bladesmith test that seems realistic to me. Does it give you any numbers? No. Does is accurately measure a specific property? No. But it does tell you something about how the knife will tolerate being dropped in later use. I started doing it many, many years ago when I used to draw my very tip back a bit to avoid having it snap off when driven into something, as so many users will do. One time UPS put the tip of a knife though the end of the packaging and the customer received a deformed tip. After a couple of stiff drinks to get over the customers phone call, I first redesigned my packaging and then set to testing those tips. I dropped in ½” steel plate to overcome the constant pitting of my concrete, and found that drawing the tip was not working- no strength. I also noticed that the small percentage of blades that didn’t pass were heat treated in the forge and none of the blades done with my current equipment showed any damage at all.
You see I do two levels of testing in my shop. The first is precise and accurate materials testing (Rockwell, Charpy and Izod impact, microscopy, abrasive wear, etc..) in order to check and zero in my heat treating processes. Then I do more general testing on the finished blade- how does that handle feel in long term use, how does it cut, how are the balance and handling dynamics, can the edge and the tip handle impact? The first level of tests remove the baised influence of the human hand in order to get the exact cause and effect in the materials, the second level of tests put it all back together to tell me about human interfacing and the "feel" that cold numbers and machines cannot give. I firmly believe the best test for this is using the heck out of the knife for its intended purpose.
I think the dumbest damned thing our business has gotten caught up in is all of these ridiculous parlor tricks having nothing to do with knife use that we like to call testing. They look great for publicity but they are “full of sound and fury, signifying nothing”. I want a knife that will cut things, bending it back and forth in a vice is just plain stupid when you ask how this applies to using a knife, as I have said before- even if you want a crow bar, they aren’t supposed to bend! We should use any test we can but we should always think long and hard about exactly what it is testing before deciding to use it, and remember if you read it in a magazine, magazines are all about getting your attention and selling advertising based in wider circulation- parlor tricks are much better attention getters than useful tests, always bear that in mind
I am for all kinds of testing and I am not saying that the brass rod test, the file test, slicing, whittling, shaving, bending, flexing, whacking, whopping, torquing are necessarily bad tests. Any test is valid as long as we know exactly what it is telling us, and more importantly what it cannot tell us. If we don’t know what it is we are measuring the only real benefit of the test is the exercise our arms might get. Thus the file test is great if we are looking for abrasion resistance or scratch hardness, it is even better if we combine it with a Rockwell test and get an overall picture of hardness in both penetrative and scratch. If we combine this information with what we see in the brass rod test and keep close track of the edge size and geometry from knife to knife, then even that test starts giving specific information. Putting a knife in a vice and “flexing” it tells us one thing, “bending” it tells us another, it is not a measure of strength at all but an indication of ductility which is the opposite of strength. But if we don’t know that the test is not even all the great of a cardiovascular workout.
All that being said- I have used the point drop test myself, and for years performed it in my heat treat demos to reinforce the differences in marquenching and traditional quenching. Since nobody would dream of taking a cold blade straight from the quench with no temper and drop it 6 feet, point first onto concrete, I enjoy the gasps as the point impacts with no damage. This is a backyard bladesmith test that seems realistic to me. Does it give you any numbers? No. Does is accurately measure a specific property? No. But it does tell you something about how the knife will tolerate being dropped in later use. I started doing it many, many years ago when I used to draw my very tip back a bit to avoid having it snap off when driven into something, as so many users will do. One time UPS put the tip of a knife though the end of the packaging and the customer received a deformed tip. After a couple of stiff drinks to get over the customers phone call, I first redesigned my packaging and then set to testing those tips. I dropped in ½” steel plate to overcome the constant pitting of my concrete, and found that drawing the tip was not working- no strength. I also noticed that the small percentage of blades that didn’t pass were heat treated in the forge and none of the blades done with my current equipment showed any damage at all.
You see I do two levels of testing in my shop. The first is precise and accurate materials testing (Rockwell, Charpy and Izod impact, microscopy, abrasive wear, etc..) in order to check and zero in my heat treating processes. Then I do more general testing on the finished blade- how does that handle feel in long term use, how does it cut, how are the balance and handling dynamics, can the edge and the tip handle impact? The first level of tests remove the baised influence of the human hand in order to get the exact cause and effect in the materials, the second level of tests put it all back together to tell me about human interfacing and the "feel" that cold numbers and machines cannot give. I firmly believe the best test for this is using the heck out of the knife for its intended purpose.
I think the dumbest damned thing our business has gotten caught up in is all of these ridiculous parlor tricks having nothing to do with knife use that we like to call testing. They look great for publicity but they are “full of sound and fury, signifying nothing”. I want a knife that will cut things, bending it back and forth in a vice is just plain stupid when you ask how this applies to using a knife, as I have said before- even if you want a crow bar, they aren’t supposed to bend! We should use any test we can but we should always think long and hard about exactly what it is testing before deciding to use it, and remember if you read it in a magazine, magazines are all about getting your attention and selling advertising based in wider circulation- parlor tricks are much better attention getters than useful tests, always bear that in mind
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Ken,
While that may be, my issue was more with the implication that a test came from the exalted Wayne Goddard and thus should not be questioned. Whether or not the information had been published is irrelevant, it's the simple spouting of "none other than Wayne Goddard" as an explanation for the "goodness" of this test that set me off really.
If we don't, as makers, make a conscious effort to have our methods of explanation and speech signify something other than the worship of a magic knifemaking totem, we will continue to be plagued with the same mystical garbage we've seen to date. It may be that in one knifemaker's shop that pointing north when quenching makes a difference. It's that maker's failure to ask "why?" that causes the damage IMHO. It very well may be that the position of windows, time of day, and distance from forge to quench tank result in a specific heat treatment that works. When that person simply says "gee, once my quench tank got moved and faced north things got better" is the point at which the trouble of mysticism begins.
Again, maybe I'm just being odd, who knows?
-d
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To me, the test proves the strength of the steel and the tip, which is where the force of impact is applied when stabbing stuff and it helps to know that the tip won't break off or deform badly when accidentally dropped. It tells me if it's too brittle or too soft. However, I don't do this kind of testing on every blade and I've only made a handful of knives so far... it's just something I wanted to throw out there. I do, infact, question the drop test as the best way to get the answers I'm looking for which is why I asked in my post above if anyone else does this kind of testing. It seems Mr. Cashen can benefit from this testing and I think he explains it well in his reply.
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which is a wholly useless point. We are interested in why YOU do it and I think the rest of your post adequately describes it.
otherwise it's just a bandwagon
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Not wholly useless! I asked if anyone else did this testing. Kevin spoke up and said that he does. It's no bandwagon. It just gives more validity to the test, to me anyway, when makers like Wayne and Kevin are doing it themselves. I just made the point because I liked how his reply was worded and he answered my question of if anyone else does this specific test. It may be useless to you but, it is not to me. I'm glad I could explain why I do it though.
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This is exactly the mentality I was trying to steer you away from earlier
I'm not trying to harp on you man, I'm really not.
I'm trying to challenge you.
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I understand what you are saying and trying to do. I think there's a misunderstanding though. I am a new maker and if guys with names and more knowledge and experience offer to share that, I'm going to listen. Trust me, I do plenty of things my way and am plenty challenged.