Inconsistent Bevel Grind Angles on FK2

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NiceNife

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I’ve had my FK2 for a few weeks and I’ve fondled the damn thing so many times that I know all of her lines and curves.

It’s still got its factory edge, but I bought angle blocks for whetstone sharpening training. You just put the knife on the angle guide and sharpen. But when I tried putting the FK2 on the 18° angle, it was off and the edge was digging into the table (I haven’t used it on the stone yet). When I tried the 14° and 15° angles, the knife’s edge laid perfectly flat on the desk. Also, on the tip, the angle is way smaller at around 11°. Doesn’t that make the tip more prone to breaking?

The other side of the knife is a nice 18°-19° as advertised.

So my question is this: how can I make both sides (including the tip) back to the 18° as the knife was meant to be? I don’t want to remove too much steel.

I’ve posted some pics of the angle guide blocks, but it’s hard to capture the bevel sitting on the desk.

Also, I’m not looking to sell this, but I do wish I got one grounded evenly.

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Well you have two choices.
1 - Sharpen it even yourself. You can do this all at once or over time when sharpening.

Or

2 - send it to CPK and let them take care of it.
I’m sure NTM would like to take a look at it. If there is a QC issue he will want to take care of it.
 
Just use it. When it gets dull, sharpen it. Rinse, repeat. Eventually, it'll be even.....assuming it's uneven to begin with and not your jig..... which you should promptly throw away for some stones and learn to sharpen by hand. Trust me, it's much more satisfying and you can touch up your blades anywhere.
 
pbubsy said:
Just use it. When it gets dull, sharpen it. Rinse, repeat. Eventually, it'll be even.....assuming it's uneven to begin with and not your jig..... which you should promptly throw away for some stones and learn to sharpen by hand. Trust me, it's much more satisfying and you can touch up your blades anywhere.
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This is sound advice.
Especially, if you’re going to be on any extended hiking/camping/hunting trips. You will definitely want to be able to bring the edge back while in the field.

The edge on my EDC2 is uneven and wonky as hell. This is my own doing. I’ve “touched up” the edge on all kinds of “whatever is handy”. It still cuts stuff great. But once the weather gets a little warmer, I will sit down and even it out on the wicked edge.
 
I THINK THIS IS BULLSHIT

If you have a problem with a knife lets talk about it. But if you're "measuring" angles with your little plastic angle blocks and deciding you have inconsistent secondary bevels grinds on your Field Knife YOU PROBABLY DON'T KNOW WHAT YOU'RE TALKING ABOUT and you don't need to be coming on here with this.

Those little plastic blocks measure to a plane. Is that the opposite bevel? That's not even a plane, it's a conic. The correct plane is the center plane, not the opposite inclined bevel. Your little kit probably doesn't do that. We can only do that by disassembling the knife to fixture on the flat surface of the tang. This is done with a big parallelogram and it's screwed down tight, not sitting on a little piece of plastic. All knives here are sharpened from this reference and are generally very accurate. WE DON'T EYEBALL ANY ANGLE. This geometry is carefully constrained.

Also, imagine in your head what happens to the geometry on a kit like that as it goes around the tip. If the angle stays the same at the tip RELATIVE TO THE REST OF THE BLADE WITHOUT BEING TURNED what would your edge angle become at the point? Do a thought experiment and think about what would happen if the tip came all the way around to 90 degrees? The edge at your point would require raising the butt and your angle would approach 90 at the tip. Think about this a minute, it isn't intuitively obvious to some people. These fixed systems generate an obtuse point. The geometry needs to be turned to remain perpendicular to the edge to maintain a consistent edge grind geometry. Your little kit doesn't do that. You may or may not understand this, depending on your mechanical reasoning ability, but a person could misunderstand what they're looking at and think the tip is too acute. But there is really no plausible mechanism in our setup that could create an acute point. Within the normal operation of our sharpening system it is geometrically impossible.

If you saw and understood the principle our sharpening setup you'd understand how a narrow tip angle or a under spec grind angle isn't a failure mode. Or one side being run at a different angle from the other. That's just not how it works. It is not something that an operator or machine can screw up, it is constrained by the nature of the manufacturing process. But could easily be created by some shitty grinding system like you're using. And that is BY FAR THE MUCH MORE LIKELY EXPLANATION FOR THIS.

This is the 3rd time in our company history that a person has thought they had a real problem with a knife we made. The other two times we dealt with the problem and things like using a steel tailgate as a cutting board and loosing the razor sharp edge on a skinning knife were resolved without a problem. But you're the first person in our history to come on a public forum like this and suggest we're doing something of this nature incorrectly at this magnitude and honestly I'm pissed off. I am pissed off that you would come on my forum and accuse us of a problem of this nature without talking to me first and apparently without an understanding of what you're doing.

If you'd like a refund I will gladly give it. Return the knife for your money back and that's the end of it.
 
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Nathan the Machinist said:
I THINK THIS IS BULLSHIT

If you have a problem with a knife lets talk about it. But if you're "measuring" angles with your little plastic angle blocks and deciding you have inconsistent secondary bevels grinds on your Field Knife YOU PROBABLY DON'T KNOW WHAT YOU'RE TALKING ABOUT and you don't need to be coming on here with this.

Those little plastic blocks measure to a plane. Is that the opposite bevel? That's not even a plane, it's a conic. The correct plane is the center plane, not the opposite inclined bevel. Your little kit probably doesn't do that. We can only do that by disassembling the knife to fixture on the flat surface of the tang. This is done with a big parallelogram and it's screwed down tight, not sitting on a little piece of plastic. All knives here are sharpened from this reference and are generally very accurate. WE DON'T EYEBALL ANY ANGLE. This geometry is carefully constrained.

Also, imagine in your head what happens to the geometry on a kit like that as it goes around the tip. If the angle stays the same at the tip RELATIVE TO THE REST OF THE BLADE WITHOUT BEING TURNED what would your edge angle become at the point? Do a thought experiment and think about what would happen if the tip came all the way around to 90 degrees? The edge at your point would require raising the butt and your angle would approach 90 at the tip. Think about this a minute, it isn't intuitively obvious to some people. These fixed systems generate an obtuse point. The geometry needs to be turned to remain perpendicular to the edge to maintain a consistent edge grind geometry. Your little kit doesn't do that. You may or may not understand this, depending on your mechanical reasoning ability, but a person could misunderstand what they're looking at and think the tip is too acute. But there is really no plausible mechanism in our setup that could create an acute point. Within the normal operation of our sharpening system it is geometrically impossible.

If you saw and understood the principle our sharpening setup you'd understand how a narrow tip angle or a under spec grind angle isn't a failure mode. Or one side being run at a different angle from the other. That's just not how it works. It is not something that an operator or machine can screw up, it is constrained by the nature of the manufacturing process. But could easily be created by some shitty grinding system like you're using. And that is BY FAR THE MUCH MORE LIKELY EXPLANATION FOR THIS.

This is the 3rd time in our company history that a person has thought they had a real problem with a knife we made. The other two times we dealt with the problem and things like using a steel tailgate as a cutting board and loosing the razor sharp edge on a skinning knife were resolved without a problem. But you're the first person in our history to come on a public forum like this and suggest we're doing something of this nature incorrectly at this magnitude and honestly I'm pissed off. I am pissed off that you would come on my forum and accuse us of a problem of this nature without talking to me first and apparently without an understanding of what you're doing.

If you'd like a refund I will gladly give it. Return the knife for your money back and that's the end of it.
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Whoa... Sorry, Nathan. Didn’t mean to offend. Didn’t mean to come off as if I knew more than you or anyone. Didn’t mean to come off as I was attacking your work. And I definitely didn’t mean to come here to say “you fucked up”. Your response really caught me off guard. I would have came to you first, but I thought maybe I had bothered you enough and went to the fans for suggestions first.

These are indeed cheap $10 plastic toys. All they do is measure angles from 10° to 20°. Sure, these pictures are crap and don’t prove anything, but they’re posted here just to show how I eyed the angles. I’ll be the first to admit that my eyes aren’t perfect either; however, it is easy to take ONE angular plastic piece and see that it fits on one side of the bevel, and then flip the knife over and see that it does NOT fit the same way as the other side. Any amateur can do this and see that the both sides are not even. I don’t need a high-tech, expensive machine to do this comparison. Also, these bevels on each side are VISIBLY different to the naked human eye. I will attempt to take a good enough picture to show this difference.

Again, I apologize if I appeared to come as attacking your work or reputation — I just thought it’d be something this community had experience with or had ideas fixing. I was obviously ignorant there. You are understandably mad for that, but I am disappointed that you are so dismissive of this issue and think yourself to be so perfect.
 
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Once upon a time along ago, I sold on a couple of original FKs (the biggest mistake of my tenure on here) when the sub was just in its infancy. I let those D3V FKs go for $240-$250 by just just addeding $20 to the CPK prices to cover for PP & shipping. One of the people who ended up with one was very unhappy because he had thought that I sold him a CPK that some novice (maybe me?) had tried to sharpen on a system like the Sharpmaker (didn't own a SM at that time). He had PM'ed me that he had acquired Carothers Knives in the past and "no way Nathan would sent a knife out to his customers in that shape". I got pretty upset because it was insinuated that I had mocked around with the edge which I had not, or worst I was going to get someone's use and abused FK in return!

What to do? I contacted Nathan directly and he was super cool about it. Nathan said something to the effect of, "someone received a knife that they are not happy with, not the end of the World!. Have him send it back to me for inspection and correction or full refund, whatever he wants". I followed up and the guy never sent anything back to Nathan so I contacted him again just because he had stated to me that "he could not in good conscious sell or give that knife to anyone else being in that shape", I even offered him $25 above his cost plus his return shipping (IIRC) at which point he told me that he decided to keep it and perhaps hit up Nathan later on. I don't think that he ever did, he does stop by once in a while be he's not a regular... Anyway, moral of the story is that misunderstandings happen and that Nathan absolutely stands behind his work and he knows that he's not infallible. At that time he disclosed to me that in all the years in business he only had one such complaint, so maybe my case was another one since his recent tallies have gone up? :D

NN, what you did was not cool by opening a whole thread about this specially since you do not seem to have a great command of geometry which is obvious with the planes of reference which you have cited as your reference points. There's already a thread regarding FK2, so why not post something in there if you could not reach Nathan by PM or why not post in Ask Nathan thread?

In closing with regards to what Bob is referring to above:

https://www.bladeforums.com/threads/the-ask-nathan-a-question-thread.1425245/page-86#post-18165463

There's some questionable attitude that is not too pleasant. Call me a koolaid drinking fan or what not, but I don't think that Nathan is perfect or that he has claimed to be perfect. It's just that he understands geometry of knives better than both you and me.
 
NiceNife said:
You are understandably mad for that, but I am disappointed that you are so dismissive of this issue and think yourself to be so perfect.
Click to expand...

You don't need to be rude. If you had handled this via email or PM your issues would've been addressed quickly and professionally.

CPK customer service is second to none and Nathan stands behind his product 110%.

As it is, you've simply insulted Nathan and agitated this nice family of CPK users. Maybe that was your intent?
 
NiceNife said:
*snip*

I would have came to you first, but I thought maybe I had bothered you enough and went to the fans for suggestions first.

*snip*
Click to expand...
Whatever your intent or depth of knowledge about what you are doing with your knife, I think your social/life skills leave a lot to be desired. Nathan's response in this thread came less than 3 hours after your original post, even though he is no doubt busier than a one-legged man in an ass-kicking contest. Had you gone to him first with your concerns, I think you'd have been met with a far different response than what you received. It's too bad really because it's painfully clear to me that the whole CPK crew busts their asses relentlessly in many ways, just one of which is making their customers happy. Rather than approach them with an issue that you felt was significant, you opted to do an end-run around them and approach the masses here. Yep, you got answers, but unless you're unbelievably ignorant, you already knew that your options were to ignore the perceived issue, try to address it yourself, or try to address it with CPK. You really did not gain anything, and in fact have lost a lot of credibility and any belief by folks here that you have any common sense. Hopefully you can learn from the error of your ways.
 
NiceNife said:
Again, I apologize if I appeared to come as attacking your work or reputation — I just thought it’d be something this community had experience with or had ideas fixing. I was obviously ignorant there. You are understandably mad for that, but I am disappointed that you are so dismissive of this issue and think yourself to be so perfect.
Click to expand...

I don't think myself so perfect. With 25 years of production manufacturing experience I know that I can screw up in many new and imaginative ways. It's something I lose sleep over. I am occasionally caught off guard and blindsided by things I never envisioned possible or anticipated. That shit does occasionally happen sometimes and it's humbling when it does.

I try to measure and control variables and edge angle is a big one. This is something that I think we have figured out. I also think we're probably about the best in the industry controlling edge angle because we use a parallelogram when we sharpen against a measured angle on a rigid platen. So when some guy comes on my forum and, despite all my efforts to perfect and control this variable, starts a thread called "Inconsistent Bevel Grind Angles on FK2" and describes inconsistent angles from one side to the other and an acute point angle (when I understand how the process works and how this is almost impossible) and then goes on to show their plastic wedge methodology I feel a little incensed.

Please, send the offending knife back and I will look at it carefully. If this problem exists I would really like to know about it. I believe that this geometry is tightly controlled and there is no potential mechanism that I can visualize that would allow this angle to vary from one side to the other or become acute at the tip. I am setup to confirm or disprove this and I would like to see what you're seeing. If you'll send the knife back I can tell you with some certainty if there is problem.
 
ALWAYS contact the maker, craftsman, or tradesman FIRST. Period. This is not a game, suitable for misunderstandings; this is someones livelihood and raison d'etre that you are besmirching without first extending them the most basic courtesy of clarifying how your situation has come to pass- by the only entity that could truly do so.
 
Casinostocks said:
Once, I sold on a couple of original FKs (the biggest mistake of my tenure on here) when the sub was just in its infancy. I let those D3V FKs go for $240-$250 just added $20 IIRC to cover for PP & shipping. One of the people who ended up with one was very unhappy because he had thought that I sold him a CPK that some novice (maybe me?) had tried to sharpen on a system like the Sharpmaker (didn't own a SM at that time). He had PM'ed me that he had acquired Carothers Knives in the past and "no way Nathan would sent a knife out to his customers in that shape". I got pretty upset because it was insinuated that I had mocked around with the edge which I had not, or worst I was going to get someone's use and abused FK in return!

What to do? I contacted Nathan directly and he was super cool about it. Nathan said something to the effect of, "someone received a knife that they are not happy with, not the end of the World!. Have him send it back to me for inspection and correction or full refund, whatever he wants". I followed up and the guy never sent anything back to Nathan so I contacted him again just because he had stated to me that "he could not in good conscious sell or give that knife to anyone else being in that shape", I even offered him $25 above his cost plus his return shipping (IIRC) at which point he told me that he decided to keep it and perhaps hit up Nathan later on. I don't think that he ever did, he does stop by once in a while be he's not a regular... Anyway, moral of the story is that misunderstandings happen and that Nathan absolutely stands behind his work and he knows that he's not infallible. At that time he disclosed to me that in all the years in business he only had one such complaint, so maybe my case was another one since his recent tallies have gone up? :D

NN, what you did was not cool by opening a whole thread about this specially since you do not seem to have a great command of geometry which is obvious with the planes of reference which you have cited as your reference points. There's already a thread regarding FK2, so why not post something in there if you could not reach Nathan by PM or why not post in Ask Nathan thread?

In closing with regards to what Bob is referring to above:

https://www.bladeforums.com/threads/the-ask-nathan-a-question-thread.1425245/page-86#post-18165463

There's some questionable attitude that is not too pleasant. Call me a koolaid drinking fan or what not, but I don't think that Nathan is perfect or that he has claimed to be perfect. It's just that he understands geometry of knives better than both you and me.
Click to expand...

Sure, I remember that. I was new and had thought that Nathan was interested in a custom I proposed. Nathan had directly responded to the request, so why wouldn't I have taken him seriously? I was laughed right out of this sub forum by the two big dogs of this sub. This is why the other newbies like me were so turned off by this community of elitists to the point where some are publicly calling you out and stating that they will not buy a CPK because of your toxic attitudes. This happened in a recent Friday sales thread.

Betzner and all others who don’t want to believe there could never go wrong with a knife can feel free to ignore me. I’m continuously shocked by the immaturity of the self-proclaimed “popular” regulars with the most “street cred” here. Not to worry though — I will never post here again once I express my concerns.

It's a true shame that a community like this would get so defensive about a possible flaw being pointed out in the forum. A possibility of a flaw should be discussed openly... unless there's a rule that nothing negative can be posted and only "I love Nathan" threads are allowed.

To those who want to set aside their fangirl attitudes and try to reason, here are some more pictures comparing the two sides of the FK2's edge. Keep in mind that it's difficult to have an amateur picture accurately show the difference in bevel width, but if you held the knife yourself, you could easily see the difference.

The wider side is the side I've estimated to be 14 to 15 degrees, while the thinner side is closer to the advertised 18 degrees. I just ask that people view these from an unbiased standpoint rather than getting defensive and saying, "your shitty sharpening system sucks" or "nothing could possibly go wrong with CPK".

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