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Knife Lore or maybe Edge Lore ( edge geometry )

old4570

Malcolm Douglas
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Here is a topic that just about everyone has an opinion on .
Some of those opinions are born from decades of experience and others from ignorance .
So who exactly should you be listening too ? ( Wow , what a good question if I say so myself )

Answer = Listen to your knife ! ( What ? )

Generally , knife bevels / edges are around 20 to 25 degrees .. ( That's each side ) For a total of 40 to 50 degrees ( In total - factoring both sides )
It is the norm to simply quote one side for the angle of the bevel / edge . ( Or half of the total )
That norm was established a very long time ago .

And since then there have been advancements in blade steel .
Steels are harder wearing and tougher .
So edge bevels have gotten tighter , these so called super steels can handle 18 degree bevels or even say 15 degrees .
A tighter bevel gives you more cutting power , as well longer life as the edge is narrower .
So lots and lots of pluses .

Butt & it's a huge massive butt !
Phoney baloney / BS / steel ...
That's right ...
A) Anyone can print anything on a knife . How easy is it to etch M390 onto a 420 blade ( very easy )
B) How many people actually test their knives ? A very small minority
C) And how many test Rockwell or have access to metallurgy testing ?

So the truth is , most of use are ignorant of the facts .
Only through testing have I personally been able to at least get an idea of performance levels for various steels .
And by no means are those results consistent from one knife to another .
Just so many variables ..
But , if you own enough knives , you can ball park results at the very least .
But Im running off at the mouth again .

The EDGE ...
How well the edge is formed / ground / done ... Very much dictates the performance of the knife .
You would think , sharp is sharp right ?
And that steel is steel ?
My TS did 300 on the factory edge ( D2 ) , that was rather impressive for a factory edge and is getting into what I consider the D2 performance ballpark .
But when I put a freshly ground edge on the knife I saw how badly the factory edge had been done ( all the mistakes ) .
And that edge did 650 on my test ... At the very least the blade steel is good ( really good for D2 )
But it also showed me the difference that a clean even error free bevel can do .

So , for me ( my opinion ) . A nice clean bevel with as few errors as possible is what you want .
Once you can lay down a clean bevel ..
You can start to worry about the angle you want to put down ( Plenty of stuff on youtube ) .
You can be as brave as you like , and push boundaries if you like .
Or you can just put down something tried and true .

Bevel Lore -

Check out the internet .. So many edge profiles you can shoot for .
Variable aedge geometry , or different angles for each side .. Put down 22 on one side and maybe 18 on the other side .. ( It's a thing for some ) I mean why not just do 20 on both sides ?
There is no right and wrong , there is only what works . ( Or does not )

Edge Lore -

Or should that be finish ? Grit folks ! Yes , just how much effort do you put into that edge ( polish ) ..
Some folks ( me ) , just dont bother doing a polish at all . I might de burr @ 800 grit on the guided knife sharpener , but that's it .
And others will swear black N blue that a 10,000 grit polish is the only way to go .
Again , I say do what works for you .

( My experience )
If your goal is to slice paper , then by all means enjoy that 10,000 grit smooth slice thru the paper ( it is sweet ) .
On the guided knife sharpener , I use a 180 grit diamond ( probably worn to 400 grit now ) and then a 800 grit stone to de burr .
Yes , I will confirm that a edge that's done rough does not cut as nice as a well polished edge .
In fact on paper you can really feel the grit .
Flesh however .. Rough or polished , sharp is sharp .
My kitchen knives are either 220 grit wet stone grinder edges or guided 180 grit diamond .. And they slice meat without issue .
In fact , they have never sliced better since I upgraded (?) to a guided knife sharpener .
Just do what works ..

How ?
Obviously what works !
Butt , that huge butt again !

If you have only done it one way ? then what are you comparing too ?
It's like , you only ever drove one car ! So it's the best car ever - right ? ( It does the job )
Until , something better comes along . Something you can compare too .
So if you have 10 knives , you have 10 ways of comparing .
If you have 100 knives , you have a larger source for comparison . ( Especially if you do testing )

And the same goes for sharpening ..
If you have only done it one way , then ? What is your yardstick for performance / results / quality .
If you are happy , then great !
But then you might be a little like me and never really happy , but rather looking to do things better .
Maybe because your Covid bored ? and you want to keep your mind active ( keep your mind and your knives sharp )
We all strive to be better (?) , sharper , more experienced , knowledged and so forth ...
Anyways , I like to test and find better ways ( easier ) to do things .
I dont particularly want to spend hours on end for a mirror finished edge if ten minutes gets me the same result ..
I have only to date done very limited edge finish testing ..

And what I have learned so far ..

The cheaper and nastier the blade steel - The more a fine finish is a complete waste of time .
So if you have McNasty blade steel , there is no need to go past an initial clean bevel with say 200 grit - Just de burr it .
I have a knife AUS8 , it's McNasty .. And it has a 80 grit edge .. And it works .
If I put too fine an edge on it , it loses performance . ( This is why you ask your knife )
I have 420SS knives that dont need anything past 400 grit at all .. Again , your just flushing performance away if you try to go too fine .
Bottom line , cheap nasty steel wants a nasty edge ( Dont polish a turd ) .

If you have a $500 pocket knife equipped with super steel .
By all means give that knife some lovin , want a mirror finished bevel - go for it !
Whatever makes you happy .

What was the purpose of this post aside from Covid boredom .
Do it yourway .
But don't be afraid to try something different , cos it just might be better .
If it's not better , then take comfort in being right !

Methods ! of SHARPENING ...

Not going to get too much into this ... But there be 3 main ways ..

Hand sharpening - To get a true performance edge takes skill .. Not many people are that skilled . Yes , most people can make the knife sharp ! But sharp and performance do not go hand in hand .. A knife can be razor sharp and poor performing at the same time .. ( Gospel )

Guided knife sharpening - Probably the easiest way to get some sort of performance . Unfortunately guided knife sharpeners can still follow bad grinds . Much better results generally than hand sharpening .

Machine sharpening - Way many machines out there . The one I chose puts down a nice clean straight bevel and does not follow previous grinds ..
Dont think I could live without one now . ( You know - that thing about something better coming along the way ) .
For doing a bevel , yeah ... It be superior .
Once you have done a straight bevel .. Edge maintenance is easy . + If you need to , you can re sharpen on the guided knife sharpener as the bevel is straight . You should only need to grind once every 5 to 10 years unless your knife gets seriously abused .
Obviously the problem with this is , it really shows up bad edges ! Some edges look like they were done by some one blind . It's an eye opener for sure !

Does anyone want me to rant about something specific ?
bevels with micro bevels , differential sharpening , guided sharpening , de burring , stropping , ......... It's all good fun ( Knowledge ) .
It's such a varied and broad subject ..
Books have been writen on just a single way of sharpening ( ? ) , well ...
 

Le Loup

Rüdiger Nehberg
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All I can say about this is that most of it goes right over my head. I carry three knives in the bush, I carry a clasp knife for every day use, we have quite a few kitchen knives, I sharpen them all the same way, all at the same angle, & have not had any problems.
Keith.
 

old4570

Malcolm Douglas
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All I can say about this is that most of it goes right over my head. I carry three knives in the bush, I carry a clasp knife for every day use, we have quite a few kitchen knives, I sharpen them all the same way, all at the same angle, & have not had any problems.
Keith.
Edge geometry / bevel geometry ..
It's as simple as 1+1 = 2
Or it can be slide rule complicated .
There is something for everyone .
I barely touched on the possibilities .
Scandi / hollow ground / double bevel / triple bevel ( do we need more ? ) ( Talking about the bevel here )
I mean , the combinations are amazing .

People do the funky stuff :
A) To be different
B) To be trick
C) To have the best edge they can do , something better than average or ordinary ( extra ordinary ) .

Again , bottom line is ... Are you happy ?
Why complicate happy ? ( Don't rock the boat )

+ It's not about problems , it's about better !
A little like the guy that buys a car and is happy ..
Or the other guy that buys a car and starts doing mods , because he wants the car to be better or different .

If your a knife guy ? ( if )
There really isn't that much to talk about or argue over ( Conversation )
A knife is a knife ..
Ok , fixed blade and various forms of folders . You buy what you like ..
Then there is blade steel , in my book . The steel is either bad / average / or good .
I dont care that much about what formula the steel is composed off as long as the knife is not a RIP in my wallet . ( Cough CIVIVI )
The one thing every Joe can play with / change / mod / experiment with , is edge geometry .
No matter the knife , type of knife , or the blade steel . Everyone can put the best possible edge on that knife .
If you gain nothing , you have learned something .
Or you might double your edge retention . And learn something .
Some people find it fascinating , probably most dont give a flying .....
As for me , Im a need to know person . I want that free education . Upskill me universe ! Dont let that sponge dry up ..
 

old4570

Malcolm Douglas
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Ok ----

Let's talk about the double bevel ...
This might be one of the earliest trick / high performance edges .
You can double bevel almost any edge , think Scandi with a micro bevel .. That's a double bevel .
Also , what was (?) popular was a thinner edge , say an initial 15 to 17 degree bevel .. And then a 20 something micro bevel was put on .
Also a hollow ground bevel ( wet stone grinders ) , which is then topped off with a 20 something micro bevel ..

Why ? you may wonder ? ( Maybe )
Thinner blades / edges have better cutting power .. Longer lasting ..
But those same thin edges are weak and prone to damage when encountering hard use .
Not an issue if all your doing is slicing chicken breast .. But wood , bone , chopping etc can cause significant damage to a thin edge .

But what if you put another bevel on the edge that was far less prone to damage ? ( A .... ha )
And a trick edge was born ..
Cutting power / edge retention and some resistance to damage .

Since the 70's , blade steel has both improved and gotten worse .. ( More cheap knives )
So back in the day , if you wanted a better knife . You put the best edge on the knife you could .
Those who needed the best they could afford , had to do what they could afford to do to get better performance .
And the cheapest way to improve performance ? It's the edge of the blade .

Most people probably dont care !
But much like some , there is a group of people who care about nothing but performance ..
And these people are pushing edge technology .
Are they having sharpness competitions now ? ( I think they are )
How long before there is edge retention competition ?
 

Randall

Richard Proenneke
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I'll be happy with uniform bevels, which some of my knives still don't have (still on factory edge) :oops:. I keep stropping them till they need sharpening, then I address the bevel issue. I'm loathe to grind away good steel so try to minimise my repairs.

If I could choose, it would be between 17° and 20°. I'd decide this on use of knife - what is the purpose of the knife blade. That is of course making some assumptions based on ignorance - especially with regard to tempering / heat treat. I live with that. Softer steels at a steeper edge, harder steels at a shallower edge. I plan to buy a wheel like yours - right now I'm tied to 20° for re profiling.

Yeah, again I'd be happy with a good uniform bevel not greater than 20°. Even my cheapo axe and hatchet are at 20° - they're very nice to use (choppers not splitters) :LOL:. Getting the belly and point even too - I think that's the limit of my skills.

I do believe that there is a big area of ignorance in current trend - mirror finish. Sometimes a fine saw edge is better with some steels and use (ie sharpened with a coarser stone might make them more useful / versatile). Mine all eventually get mirror edges via stropping; I'm not too concerned with trying to get a mirror edge via stones etc. Although I'm guessing the micro saw thing would be better with harder steels.

Knowing your knife is another thing. I have a cold steel mini tuff lite that is hollow ground and super thin behind the edge, and reasonably soft steel. It is marketed as a hard use knife, and looks like it. In reality though it isn't, it is more akin to a cut throat razor, even more so because of the height of the blade. I swear it slips between the atoms of nylon ties. Because I usually have this when I'm on the mtb, I've used it to shave around wounds before applying a dressing. It gives me the willies to shave with it - it really wants to draw blood :oops:. I also shaved a sheep with it once; it was badly tangled up in old fencing wire. I'd like to know what the farmer thought when he saw his sheep afterwards - it wasn't a uniform shave, kind of patchy punk style. I enjoy that knife and use it often, but gently :), and strop it frequently. Lots of different knives with different designs - I'm happy with most of them and accept their strengths and limitations. I usually have something on my hip that is useful.
 
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old4570

Malcolm Douglas
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Generally , I go coarser for softer steel . And a harder steel can take a finer finish .
I am yet to fully test this , though I have done a little testing .
I need some representative knives .
I have a box full of what I consider junk knives , so the soft is taken care off .
As the weather / Covid / and time permits ..
I will knuckle down and do a proper edge test . ( Grit VS Grit )
Soft / medium / hard , need to be represented . ( ? )
So much testing I want to do ..
 

Randall

Richard Proenneke
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That's interesting; a different perspective. I was thinking teeth (under a magnifying glass) on soft steel wouldn't last long, therefore go for a fine finish, even a polish. There's more material support there with no teeth, or microscopic teeth. I've been doing things opposite to you; although eventually they're all mirror finish after months / years of stropping.

It sounds as though you enjoy doing this, which is awesome for us because you share your results. I have a dog that lets me know if we're running out of daylight and it's time to go bush :); just saying, I hope you make use of the good weather too.
 

Randall

Richard Proenneke
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Good point! I never considered those - both cheap steel and excessively large teeth.
 
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Randall

Richard Proenneke
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it's a good review if you're only sharpening big full flat ground kitchen knives with no bolster at the heel - which is exactly what he is using :(.

If you have smaller knives with minimal flat spaces on their blades, or not very high blade, or hollow ground with no flat spots, about the only thing that will work is the sharpmaker. Otherwise the clamp is too big for knives that don't have high blade, or the clamp has no where flat to clamp; the bolster at the heel will hit the side of that electric pull through sharpener, which means you can't get the 1st cm (just in front of the heel).

The manual pull through (not the fiskars) should work with everything - I thought they were notorious for removing a lot of material.
 

old4570

Malcolm Douglas
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You buy what will work for you ..

I was grinding steel today ..
Civivi Dogma D2 got a fresh edge ( This knife has been a fail so far )
As did another FAIL to date Manley D2 slip joint
As well two Chinese knives ( one is new and untested )
Will be slicing rope on the morrow .
+ The $25 to my door Mora came today . ( So no excuse for not playing with Mora's )
Except , I will need more rope .. ( Just remembered )
 
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