Managing expectations of edge retention

You know, i bought a para 3 in maxamet a couple years ago. I recently made a new blade to replace it. Because it had gotten sharpened down to the point where it needed a regrind twice.

Pretty much everyone has been shocked by this. The thing i tell them is. Since ive gotten that knife, it has literally been the one ive used everyday, doing everything, and to keep it actually sharp it needed sharpening. Not to mention chips. That certainly did take a good bit of the life out of the knife, but if i needed to use a knife, i just used it, and worried about fixing it later.

Cutting kaowool, it doesnt matter what kind of blade you have thats going to wear it, along with about 1000 other ways i abused it.
 
Blankblank said:
You know, i bought a para 3 in maxamet a couple years ago. I recently made a new blade to replace it. Because it had gotten sharpened down to the point where it needed a regrind twice.

Pretty much everyone has been shocked by this. The thing i tell them is. Since ive gotten that knife, it has literally been the one ive used everyday, doing everything, and to keep it actually sharp it needed sharpening. Not to mention chips. That certainly did take a good bit of the life out of the knife, but if i needed to use a knife, i just used it, and worried about fixing it later.

Cutting kaowool, it doesnt matter what kind of blade you have thats going to wear it, along with about 1000 other ways i abused it.
Click to expand...

^that's literally what got me into knifemaking
 
JoeBusic said:
Edge retention is related to wear.
Edge holding is related to geometry. If it chips or rolls it's to thin to hold an edge for the task.
Just because "holding" creaps under the radar and nobody notices, doesn't mean it's right. When it becomes a standard flaw in definitions it dilutes language and communication towards anarchy.
Click to expand...
I would say the edge retention, and edge holding is basically the same thing. Retaining, is holding something.

Retention definition -
  1. the continued possession, use, or control of something.
    • the fact of keeping something in one's memory.
      "the children's retention of facts"
    • the action of absorbing and continuing to hold a substance.
      "the soil's retention of moisture"
 
Blankblank said:
I would say the edge retention, and edge holding is basically the same thing. Retaining, is holding something.

Retention definition -
  1. the continued possession, use, or control of something.
    • the fact of keeping something in one's memory.
      "the children's retention of facts"
    • the action of absorbing and continuing to hold a substance.
      "the soil's retention of moisture"
Click to expand...
Yes. Confirmed correct. What I was referring to is "stability". Already a set definition but noone chipped in with it.
 
Looks like bladeforums.com is starting to go the way of longrangehunting.com. Used to be a few guys geeking out on the details and learning from each other, to a bunch of opinionated internet geeks that probably have never touched a rifle or knife pissing off all the guys we used to learn from so they don't want to post anymore. Now you get threads that go for pages about opinions and hurt feelings.
Great topic from Devin...Missed opportunity for a great thread.

On that note, agree completely that much of this stuff gets overhyped. Most people won't notice the difference in edge retention during normal use, but everyone who sharpens will notice the difference when sharpening. I prefer a steel that holds up "decent" on the charts but sharpens back up easily over really high edge retention because I don't mind sharpening, and it's not like those basic steels don't hold up. I made a 3.5" 15n20 hunter last year. It's not magic, but I cleaned 3 elk, and 5 deer. ( just gutting, not quartering and skinning) it's due for a touch up now, but stroping is probably all it needs. That's a decent amount of work for a little knife and it's nothing special.

Point being...you should all do what I do. Throw away everything that isn't 15n20, it's the best most amazing knife steel on the planet perfect for everyone and everything!!! Seriously though...it's my favorite.
 
WAY before I became a knife nut, my first real decent quality knife was one of the old Cold Steel Master Hunters in Carbon V, which I recall is Sharon 0170-6C, basically a 1095 Cro Van. Like nmbarta mentioned about the 15n20, I was really impressed with the edge retention after gutting (not full processing) a handful of deer. It would still shave hair easily. So all you need is 15n20, and Carbon V!
 
Hmmmm ...
A) Finding the angle of the dangle the blade will support .. The tighter the edge angle , the more it will cut ( last longer ) , but a tighter bevel is also a weaker bevel . So ... It is up to the user to find the angle the knife will support for the best edge retention .
B) What type of sharpening ?
C) How much time do you invest ?
D) Is edge retention that important to you ?
E) Edge maintenance . ( Or ease of re sharpening ) Is that important .

The important thing is , if it works for you ? / and if your happy ?

Edge retention or performance :

Imagine paying $500K for a car ..... For a moment ! & You don't care about mileage / power / fuel economy / handling ...
You happy because the car feels great when you sit in it , it sounds great , and it looks great ... ( Many people )
So why should knife people be different ? The knife looks great , the knife feels great , is made from great materials and has a high price tag . ( People are happy )
So you buy a $500 pocket knife and your happy ..
But what if a $50 pocket knife looks almost as great , feels almost as great .. Is made from budget friendly materials and kicks the $500 knife to the curb in actual use ( performance / edge retention ) Then what ?
This topic is essentially a black hole ! The variables are so large and the arguments so varied ..

So .................. Are you happy ?
What ever you paid / what ever blade steel you chose / how ever you sharpen it / are you happy ?

There is a reason 99.999%+ of people don't test performance / edge retention .. They don't want to know !

Then there is that 0.001% or less that do want to know . Who will manufacturers cater too ? The 0.001% or less or the 99.999% ....
 
I think something that's often overlooked is the distinction between fine edge retention and working edge retention, where fine edge roughly correlates to shaving sharp and working edge correlates to paper slicing sharp. Working edge is where super steels really shine compared to lesser steels. Maxamet might not hold a fine edge much longer than a well-treated M390, or even 9cr, but it will hold a working edge 2-3x longer.

I think that leads many folks to conclude that the differences between steels are overblown, when in fact the differences are substantial ... but only if you put a lot of wear on your blades between sharpenings.
 
thermocouples (k type) are made of nickel and NiCr alloy, 90 and 11 wm/k thermal conductivity respectively. steel is ~40 wm/k 20-60 depending on alloy content. https://www.engineeringtoolbox.com/thermal-conductivity-metals-d_858.html
so idk if grinding on a thermocouple directly would produce an useless result. I can't find it atm* but before Landes there was a similar study on embedded thermocouple measurements and grinding wheels. They found that, using water cooling, if speed and feed rate/pressure was too high, the result was a very thin, hardened layer (the steel surface reached austenitizing temps then was quenched by the water) above several mm of a softened base. that would explain why some people get bad results like excessive belt wear from trying watercooled setups, despite using belts that use waterproof binders.

* Das Schleifen von rostbeständigem Stahl mit magnesitgebundenen Schleifsteinen und die Beeinflussung der Werkstoffeigenschaften durch die Schleifwärme by Stüdemann/Lauterjung/Grube 1980 https://doi.org/10.1007/978-3-322-88475-6_8 pages 74 - 76 - available via springer or sci-hub
 
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Just to be clear about Roman Landes' study - It sounds like this is referring to grinding and not hand sharpening? A lot of sharpening systems these days use dry stones of various materials, and the thought never really occurred to me about apex temperatures with them (I mean, surely it's not hitting 2000F like in the study, but even > 350F is clearly a problem.). Maybe I should start wetting my stones just to be safe!?!
 
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