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Sometimes you don't know as much as you think you know

Posted by CliffStamp 
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Re: Sometimes you don't know as much as you think you know
September 13, 2014 10:21AM
first thing I thought of is laser sharpening could rapidly heat the edge like friction forging, one of the BF posters mentioned that
Re: Sometimes you don't know as much as you think you know
November 05, 2014 05:37PM
As another failed experiment :

I had planned to do an edge retention trial, push cutting on magazine paper. Now before anyone sort of raises objections, I had a bunch of it which I had to shred anyway so I decided to do it with a knife vs machine as machines are lame anyway and tend to produce charts and graphs.

The problem is that even with the worst knife I have it simply isn't practical. I filled an entire huge box with shredded magazine paper and a 3Cr13 knife so soft it is easily filed still shaves arm hair. I was doing runs of thousands of cuts of paper 11" long and seeing no measurable decrease in sharpness even with the cutting constrained to a small section of edge.

I was planning to run this with AEB-L and then Elmax and then 10V. Forget that, I will convice Old Spice to trade me his Mega Sceptile before that, though I might do 121REX if this knife ever decides to go blunt before the stockpile of magazines runs out.

--

I was using :

-edge at 5 dps
-micro-bevel at 5 dps, 8000 henckels

The edge would pass all HH tests depending on what hair I used, some more so than others.



Edited 1 time(s). Last edit at 11/05/2014 05:39PM by CliffStamp.
Re: Sometimes you don't know as much as you think you know
November 05, 2014 05:46PM
What are the HH test?

_______________________________________________________________________________________________

Always in search of a good choppa'
Re: Sometimes you don't know as much as you think you know
November 05, 2014 05:55PM
Much more than you ever wanted to know : [straightrazorplace.com] .

That is an extremely well written article, +nerd points to the guy who wrote it.
Re: Sometimes you don't know as much as you think you know
November 05, 2014 06:06PM
Thank you. Definite nerd points, but very well done.

_______________________________________________________________________________________________

Always in search of a good choppa'
Re: Sometimes you don't know as much as you think you know
November 05, 2014 06:29PM
The next time you are so inclined, try to get HH5 off a King 1000 with one of those crazy hard to sharpen knives you have.
Re: Sometimes you don't know as much as you think you know
November 05, 2014 06:38PM
Ha, I don't think I've even made HH3 using the Spyderco UF. Tomorrow I should have some free time and I'll probably do some sharpening. If I do I'll video trying the HH test. Maybe I'll even take it easy and try it with something like J's 14c28 instead of the crappy kitchen knife.

_______________________________________________________________________________________________

Always in search of a good choppa'
Re: Sometimes you don't know as much as you think you know
November 05, 2014 06:56PM
1000 king hht5 in the recurve of your kukri.

www.theflatearthsociety.org

BIGFOOT FINDS YOU, YOU DON'T FIND BIGFOOT!



IT IS THE E-NEP THROWING BROTHERHOOD
Re: Sometimes you don't know as much as you think you know
November 05, 2014 10:03PM
Here is the paper :



This is ~5 kilometers of paper cut, as a result it could not even take the shaving edge off the 3Cr13 blade.

I have cut this up before but never seriously as an edge retention trial. I shred it all the time to paper other paper, compost, etc. . Anyway at least this should convince you that the nonsense about paper blunting a blade is false.
Re: Sometimes you don't know as much as you think you know
November 05, 2014 10:22PM
Still don't believe you. You'd need at least a good old carbide or two to cut that paper. Plus it looks more like 4.3 km to me.




And on a serious note, I just spent the last 3 hours futzing around with the Omura 150 and then the King 1K trying to sharpen a bill hook and one of the kitchen knives fro my videos...talk about one of those extremely frustrating days. Part of the bill hook would just not get sharp off the King 1K...I'm hoping it's still just overheated metal from the power grinding / special treatment. And then the darn kitchen knife. I got a part of it to start a push cut on z paper...won't finish it though. And i only reached HH0, lol. Would do nothing to a free hanging hair. Bah.

_______________________________________________________________________________________________

Always in search of a good choppa'



Edited 1 time(s). Last edit at 11/05/2014 10:45PM by C Amber.
Re: Sometimes you don't know as much as you think you know
November 05, 2014 11:00PM
It is because you don't have any Sasquatch hair

www.theflatearthsociety.org

BIGFOOT FINDS YOU, YOU DON'T FIND BIGFOOT!



IT IS THE E-NEP THROWING BROTHERHOOD
Re: Sometimes you don't know as much as you think you know
November 05, 2014 11:03PM
If I had that I might as well cut .25" hemp.

_______________________________________________________________________________________________

Always in search of a good choppa'
Re: Sometimes you don't know as much as you think you know
November 05, 2014 11:29PM
At first glance I thought the Mega Sceptile was a lymph node.

Re: Sometimes you don't know as much as you think you know
November 06, 2014 12:15AM
Quote
C Amber
Still don't believe you. You'd need at least a good old carbide or two to cut that paper.

Interestingly enough, assuming this steel has poor thermal processing it is likely to have more primary aggregate than a sensible hardening, maybe that is the magic.


Quote

And i only reached HH0, lol. Would do nothing to a free hanging hair. Bah.

The thing about this test, being semi-serious, is that like most of the ones people use it is very variable. If you have really fine hair this get hard fast, if you are some kind of half ape-man like most of the people here it is pretty easy.

If you wanted to make it even half sensible quantitative, which a lot of the knife community is really resistant to, then using a monofilament fishing line or similar would be sensible as anyone could just buy it vs sending boxes of hair around which is more than a little creepy.
Re: Sometimes you don't know as much as you think you know
November 06, 2014 12:57AM
Hmm, on the one hand you're saying maybe carbide is the magic, and so basically that 10V steel is the greatest thing ever. But on the other hand you used sciency words like "thermal processing" and aggregate. At least you didn't try and confuse me with graphs.




With regards to the test, I figured it was very hair dependent. The hair I chose was very fine, but even so, my trying it was more on a lark than anything else. I didn't expect to get very far with it as I don't think I'm close to those standards. I'd rather keep working towards the push cut off the King 1K. The phonebook paper, while I"m sure variable too, comes from the same source for quite a while and let's me have a more consistent baseline.

_______________________________________________________________________________________________

Always in search of a good choppa'
Re: Sometimes you don't know as much as you think you know
November 06, 2014 01:39AM
It is a difficult test in general. I have tried it with my wife's hair (while she sleeps) and the best I have ever done is hht4, same knife on my daughters hair ends up at 0-1. I keep my hair too short to know other than that it is my face that gets the shave.

www.theflatearthsociety.org

BIGFOOT FINDS YOU, YOU DON'T FIND BIGFOOT!



IT IS THE E-NEP THROWING BROTHERHOOD
Re: Sometimes you don't know as much as you think you know
November 17, 2014 02:02AM
This was similar to the paper trial :



I had a bunch of this as I was helping a friend this weekend who was doing some renovations at a hotel. These pieces were from curtain toppers, about 1' wide, multiple layers of fabric, heavy embroidery. It was all being thrown out. I decided to do a quick trial to see how much of an effect it had on the edge. I rolled it up into a tight roll and cut 50 sections which each required 3 slices, so 150 slices in total. No significant effect on the edge, it still shaved. Now I am sure I could have measured one with thread, but just doing a simple check the edge was not significantly dulled. It was also a very quick 60 DMT 20 dps micro-bevel on a ~15 dps edge bevel. Interesting material, but not overly interesting for edge retention because you would be looking at ~1000 slices to even have a significant effect on a basic 5Cr13 steel.

I am coming more to the conclusion that people complaining about edge retention with knives simply can't sharpen and/or are running severely mismatched apex angles and/or grit finishes. If the material is clean it takes on the order of ~1000 cuts to make a significant effect on even the most basic of steels on cardboard, ropes, fabrics and wood is even less of a factor. The only time that you don't need this huge volume of cuts is when you are looking at keeping very high sharpness. If you combine these ideas everything keeps point back to one general type of steel as being useful for blades in general. Hence likely why so many people tend to favor steels like 50100-B which was very popular in the late 90's .
Re: Sometimes you don't know as much as you think you know
November 17, 2014 02:49AM
Quote
CliffStamp
I am coming more to the conclusion that people complaining about edge retention with knives simply can't sharpen and/or are running severely mismatched apex angles and/or grit finishes. If the material is clean it takes on the order of ~1000 cuts to make a significant effect on even the most basic of steels on cardboard, ropes, fabrics and wood is even less of a factor. The only time that you don't need this huge volume of cuts is when you are looking at keeping very high sharpness. If you combine these ideas everything keeps point back to one general type of steel as being useful for blades in general. Hence likely why so many people tend to favor steels like 50100-B which was very popular in the late 90's .

I really think that the influence of sharpening technique is much larger than most people realize.

Just in the last couple of weeks as I've been spending some time playing around with sharpening techniques and progressions trying to understand what works best and why it works best, I've seen a pretty big jump in the levels of push-cutting sharpness I can obtain. That doesn't even compare to the difference from ~6 months ago when I first posted here looking for sharpening advice. From that perspective, I would now consider one of my knives dull at a level of push-cutting sharpness comparable to the maximum I could obtain then.

I think this can have a huge influence on perceived edge-retention because many people will judge edge-retention based on how long the force necessary for cutting tasks remains below a threshold they subjective perceive as excessive (and thus dull), and this will be heavily influenced by the initial sharpness obtained.

This isn't helped by how hard it is to find good explanations of how and why to sharpen a certain way. Aside from what I've gotten from here, I've had to learn a lot by trial and error, which is both a time consuming and frustrating process.
cKc
Re: Sometimes you don't know as much as you think you know
November 17, 2014 11:03AM
I wonder how this plays out with Jigged sharpening?

They obviously keep the right angle, but they can still have the wrong forces applied, etc etc.

----------------------------------------------------------------------
It's not Cliff, its Dr Stamp
#kebabstickcut, it's a thing - make it happen
Re: Sometimes you don't know as much as you think you know
November 17, 2014 01:07PM
Quote
cKc
I wonder how this plays out with Jigged sharpening?

If you do a quick scan of Spyderco's forum you see a near constant stream of the same problem reported with various jig-based systems including the Sharpmaker. The common advice also doesn't solve the problem and can leave people just as frustrated. See for example : [www.spyderco.com] where an individual gives up with a Lansky and buys a Sharpmaker. The main problem is people don't understand what they are trying to do and essentially try random things to see what happens.

Most people using jigs tend to have very poor ability to sharpen at low grits because they are focused on extreme polishes and tend to heavily favor ending with strops. A jig system removes a lot of the tools you can use hand sharpening to minimize burr formation which is why I actually find it harder to set an apex on the WE than I do freehand.
Re: Sometimes you don't know as much as you think you know
November 17, 2014 01:11PM
Quote
Steel_Drake


I think this can have a huge influence on perceived edge-retention because many people will judge edge-retention based on how long the force necessary for cutting tasks remains below a threshold they subjective perceive as excessive (and thus dull), and this will be heavily influenced by the initial sharpness obtained.

Yes, and this goes beyond edge retention as well, it is how most people judge everything. Hence why you can often tell which was the first decent knife someone bought as it often has a severe influence on their viewpoint. If most people took a standard Olfa blade and just used that as a benchmark for acceptable sharpness then it would eliminate a lot of the conflict where people are often talking about different things. If you can't get a knife that sharp then you are likely going to see compromised performance in multiple areas. In many cases then knives which are simply easier to sharpen are often those that get praised for high edge retention. In other cases people blend cutting ability and edge retention together which further generates conflicts as again they are not talking about the same thing.
Re: Sometimes you don't know as much as you think you know
November 17, 2014 08:37PM
I have bought quite a few sharpening jigs and I am still perfectly able to make a dull knife even duller or polish a sharp knife dull again.
Luckily I can nowadays figure out why it happens if it happens and also sharpen my knives to a decent sharpness.

It seems to me people hope their jigs come with a magic formula and if that doesn't work something must be wrong. Without a clue
what you are actually doing you might then easily buy a new jig hoping it has a stronger magic formula as it is way more expensive.
And yes I do have a WE. Unfortunately the basics remain the same whatever you are using.
Re: Sometimes you don't know as much as you think you know
December 22, 2014 01:50AM
Another experiment which didn't go as planned :

-12C27 / Normark
-edge finished on fine Norton Economy

I planned to cut pine until the knife didn't shave. I needed to make a big pile of shavings for an elderly friend who wanted firestarters. I did 1000 cuts between 15 - 30 cm long, filled a garbage bag, the knife still shaved. It wasn't as sharp as when it started, but I would need to carefully measure it to try to tell the difference between it and another steel.
Re: Sometimes you don't know as much as you think you know
December 22, 2014 11:09AM
I'm beginning to think that provided you sharpen without over stressing the edge and leaving a burr, any knife will cut for a long time, lol, provided it isn't damaged first.

_______________________________________________________________________________________________

Always in search of a good choppa'
Re: Sometimes you don't know as much as you think you know
December 22, 2014 11:24AM
Quote
CliffStamp
I planned to cut pine until the knife didn't shave. I needed to make a big pile of shavings for an elderly friend who wanted firestarters. I did 1000 cuts between 15 - 30 cm long, filled a garbage bag, the knife still shaved. It wasn't as sharp as when it started, but I would need to carefully measure it to try to tell the difference between it and another steel.

This is just to strengthen the idea that users (myself partially included) don't know what to expect as good performance from a knife, just makes me think of all those videos of guys doing 10 cuts in cardboard and then verifying the knife still shaves and therefore drawing the conclusion that' a high performing steel.
Re: Sometimes you don't know as much as you think you know
December 23, 2014 03:19AM
This thing is we have to be careful once we know something not to be overly harsh on people who don't.

When I started looking at "high end" knives the problem I had was I didn't have a known standard and didn't understand fully all the influences of what controls performance. It takes some time to sort it out and be able to see what is even good vs bad let alone high vs low.

The thing which would cut away a lot of the problems would be if comparisons were used, it is a small change but it would make a huge influence.

--

I tried some hardwood flooring, that is better ~500 slices about 6" long were enough to take off the shaving edge, but this still easily slices newsprint and even cuts it without a draw on a 45. But this would not surprise anyone who does wood working. Planes are commonly made out of O1, A2 etc. and they are not sharpened constantly cutting wood.
Re: Sometimes you don't know as much as you think you know
December 28, 2014 12:43AM
So I had this :



(Christmas gift).

I thought I had an excellent way to look at long term blunting in a very practical way and see what kind of "working edge" I could see/compare on a few knives as surely that dirty carpet could take the sharpness down on knives so quickly I could look at really dull knives. As it turns out, not really.

I was using an 7-8 dps edge, 15 dps x-coarse DMT micro-bevel, but comparing 12C27 (production, < 60 HRC), S30V/60 HRC and 10V 62/63 HRC didn't give the results you might expect. Results will be discussed in a upcoming video, footage is being edited now.
DK
Re: Sometimes you don't know as much as you think you know
January 10, 2015 10:39PM
why is this at the top when last post was dec 27th? is this a pinned thread?

"knives save lives" on youtube
all i want for christmas is more arm hair -DK-
Re: Sometimes you don't know as much as you think you know
January 10, 2015 11:07PM
DK, yes, that is why. He just pinned it I think.

Also, if he moves threads between subforums, even if no new posts have been made, they will show up as new threads, with every post being new.

_______________________________________________________________________________________________

Always in search of a good choppa'
DK
Re: Sometimes you don't know as much as you think you know
January 10, 2015 11:20PM
thanks! i've clicked on it looking for new info a couple of times and was wondering.

"knives save lives" on youtube
all i want for christmas is more arm hair -DK-