# Sharpness tester



## peterng (Nov 14, 2020)

Even after I found some handy tests for determining sharpness, I like the idea of having a sharpness tester that provides a measured value. Like the one in this video:



I like the looks of the chart shown at 0:16

any options other than the Sharp PT50B model seen here: Index ?

Thanks,
Pete


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## Bensbites (Nov 14, 2020)

How much of the cost is the mount vs the scale? Can you get a $20 milligram scale and come up with your own system?


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## Michi (Nov 14, 2020)

Bensbites said:


> Can you get a $20 milligram scale and come up with your own system?


The problem is that normal scales (which would be accurate enough) do not have a way to lock in the max reading, and the readout updates quite slowly, so you won't get an accurate value.

You could buy a 500 g load cell for less than $10 at an electronics outlet. Add an Arduino Uno or some such and a little program to sample an A/D converter a few hundred times a second and lock in the max. Make a simple holder with a small U-bracket and two thumb screws, and buy the filament from edgeonup.com. You could put the whole thing together for less than $30, easily. Use a fresh razor blade to calibrate, so you know at what reading you have "extremely sharp", and that should be it.


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## peterng (Nov 15, 2020)

Bensbites said:


> How much of the cost is the mount vs the scale? Can you get a $20 milligram scale and come up with your own system?


Interesting you started thinking the same way I did. Don't all digital bathroom weight scales display total weight as opposed to a real time reading? Must be some kitchen scales that do the same thing.

This is another page that shows the whole unit for sale as well as the components:  https://www.sharpeningsupplies.com/Edge-On-Up-C286.aspx

Then Michi came in with a top shelf A to Z do it yourself how to for $30 solution. Excellent options for those of us who are not over run with cash.

Thanks for kickstarting the options.
Pete


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## inferno (Nov 15, 2020)

in the end its probably cheaper to just buy the machine. it just works. unless you work for free/have unlimited time.

i've seen on yt that a certain type of fishing line will give almost identical results compared to the factory wire. thats probably the best way to save money.

also if you want to compare results with others its always best to have the actual machine, then you know its correct.


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## DrEriksson (Nov 15, 2020)

It should be noted that these tests increase the reliability of the measurement. If the goal is to measure sharpness in use, the validity needs to be questioned.


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## M1k3 (Nov 15, 2020)

Michi said:


> The problem is that normal scales (which would be accurate enough) do not have a way to lock in the max reading, and the readout updates quite slowly, so you won't get an accurate value.
> 
> You could buy a 500 g load cell for less than $10 at an electronics outlet. Add an Arduino Uno or some such and a little program to sample an A/D converter a few hundred times a second and lock in the max. Make a simple holder with a small U-bracket and two thumb screws, and buy the filament from edgeonup.com. You could put the whole thing together for less than $30, easily. Use a fresh razor blade to calibrate, so you know at what reading you have "extremely sharp", and that should be it.


I'll take 2!


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## peterng (Nov 16, 2020)

I am handy with a hammer but I am not familiar with load cells so I think I'll just buy the Sharp unit


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## amithrain (Nov 16, 2020)

I get that this is an edge tester that gives you an objective score very quickly, but I don’t really think it’s worth it when there are other fairly objective sharpness tests that can be measured with the same units. 


http://knifegrinders.com.au/Manuals/Sharpness_Chart.pdf


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## peterng (Nov 16, 2020)

wow, excellent article. Thanks for the link


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## M1k3 (Nov 16, 2020)

amithrain said:


> I get that this is an edge tester that gives you an objective score very quickly, but I don’t really think it’s worth it when there are other fairly objective sharpness tests that can be measured with the same units.
> 
> 
> http://knifegrinders.com.au/Manuals/Sharpness_Chart.pdf


Wow! One step above "Dull. The edge reflects visible light." is "Working Edge"? Nice read nonetheless.


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## peterng (Nov 16, 2020)

I wanted this to provide a real world before and after measurement for sharpening customers. Maybe I'm a nerd but I'd like to know.


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## amithrain (Nov 16, 2020)

M1k3 said:


> Wow! One step above "Dull. The edge reflects visible light." is "Working Edge"? Nice read nonetheless.


I guess our standards are too high


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## Keith Sinclair (Nov 20, 2020)

I use Feather double edge for shaving.


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## Keith Sinclair (Nov 20, 2020)

A bunch of folders many the grinds don't cut great because fat behind edge.
My Spyderco Blue or orange Hap40 will beat any of those, better grinds & steel.

Kitchen knives just cut food. Newspaper is good their example in video that blade was full.

Talking Chef Knives
If blade sails through paper lite resistance some sound knife is sharp.

If sails through paper no resistance almost no sound very sharp you are good to go.


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## Kawa (Nov 20, 2020)

In my experience, which is not the most, the sound of the newspaper is more related to a higher gritt finish (which also makes a knife sharper) then to a sharper knife.
For example: a very very sharp knife at 600 gritt will make more noice when slicing through newspaper then a 'moderately' sharp knife at 5000 gritt.



That's why its hard to have an 'objective' way of measuring sharpness.
And that expensive scale is close to one (assuming the test medium is the same every batch, every day etc.)

It's just way to expensive for a gimic, I think. But hell, I've been wanting one since I saw Ryky use it in my starting journey as a sharpener.


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## Kawa (Nov 20, 2020)

.. F#ck it.
PT50B on the way.

My boss awarded me 250,- Euro in coupons last month for being a costsaver, (which is political/subjective ******** for a manager to show that they are peoples-people, but hey, I'm not going to complain ).
Didn't know where to spend it, and already almost forgot about it.. This topic made me think

So now my boss paid for a way over the top gimic, a never needed Sharpness tester.
Thx boss!


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## Michi (Nov 20, 2020)

Kawa said:


> So now my boss paid for a way over the top gimic, a never needed Sharpness tester.


The best things in life are the ones you don't actually need


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## nwshull (Nov 20, 2020)

Do people normally assume kitchen knives have inferior sharpness to pocket and outdoor knives? To me a pocket knife is something I want a higher angle on and more stain resistance and toughness in the steel. I may take it on a week long camping trip without access to a proper sink and plenty of hard beating tasks. A chef knife is something I meticulously select the cutting ingredient, cutting board to make contact with, hand wash and dry immediately. Its got much more of a delicate edge, unless its something single task like a butcher's cleaver or deba. Aside from very high end finishing planes and straight razors I'd place kitchen knives at the top of my needs to be sharp AF list.


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## tostadas (Nov 20, 2020)

nwshull said:


> Do people normally assume kitchen knives have inferior sharpness to pocket and outdoor knives? To me a pocket knife is something I want a higher angle on and more stain resistance and toughness in the steel. I may take it on a week long camping trip without access to a proper sink and plenty of hard beating tasks. A chef knife is something I meticulously select the cutting ingredient, cutting board to make contact with, hand wash and dry immediately. Its got much more of a delicate edge, unless its something single task like a butcher's cleaver or deba. Aside from very high end finishing planes and straight razors I'd place kitchen knives at the top of my needs to be sharp AF list.



"Sharp AF" is not a technical term, according to the list. Perhaps you meant to say "nuts sharp" or "insane sharp".


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## inferno (Nov 20, 2020)

sharp pebble


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## Kawa (Nov 21, 2020)

Kawa said:


> .. F#ck it.
> PT50B on the way.
> 
> My boss awarded me 250,- Euro in coupons last month for being a costsaver, (which is political/subjective ******** for a manager to show that they are peoples-people, but hey, I'm not going to complain ).
> ...



Ordered yesterday, playtime today.

AUS 10 sakai takayuki gyuto averages 275 after 3 measurements.
Blue #2 Shiro Kamo petty averages 260 after 3 measurements.

Both have been used and can use a touchup in my opinion, especially the Shiro Kamo.

According to the scale they hand out thats a little bit more sharp then 'high end cutlery out of the box'.

I know I get my knives sharper then they were new, but I feel like I'm nowhere near what most people here achieve. Which makes me curious what the better or even good sharpeners would measure using this device.

For me, I hope I can see nuances within my own work, for example does my final stropping make my knife really sharper, or is it placebo? Or can I measure different values after different diamond pastes (0,5/0,75,1 micron) etc. What do I measure when I strop wrongly and round of my edge? etc etc.

No science, just for comparing myself with myself.


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## ModRQC (Nov 21, 2020)

Lol, because "high end cutlery OOTB" is such a constant, precise measurement of sharpness...

Also I assume that going straight from "dull" to "working edge" is logical: what good is there in describing any dullish level in between? If you cannot at least get the thing from dull to working edge, you failed, and there's no in-between it.


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## Kawa (Nov 21, 2020)

I dont read that chart as science, neither should you 

The more pressure you need to cut the medium, the duller the knife.
the chart gives an indication about what and kitchen knife edge should show of the scale. I take that for newbies, unknown users of knives. For example, if all your knives show 400 and you find them really sharp, you might want to rethink your own opinion/skills... nothing more then an indication about what you should be able to expect in some way
I can imagine that the really good sharpener isnt even satisfied with values over 200.
Its about what is your standard.


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## ModRQC (Nov 21, 2020)

M1k3 said:


> Wow! One step above "Dull. The edge reflects visible light." is "Working Edge"? Nice read nonetheless.



I had this in mind obviously...


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## Kawa (Nov 22, 2020)

ah my mistake. sorry


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## ModRQC (Nov 22, 2020)

Well IDK if you made a mistake... I don't even know if you were even replying to me or "in general". I suppose, if you were, you were reacting mostly to the first part of what I said, which was mainly ironic: from 200$ to 600$ I've seen all shades of OOTB edges, from pretty dull to real shaving sharp. 

While on this forum such a thing becomes subjective to nonsensical depths, I think all my J-knives would stand in the largely loose "high end cutlery" category for any given general population.

Whatever... I just wouldn't have chosen such a descriptor of sharpness in something serious, because it sure means nothing, even if I screw my brains trying to imagine what would be the average edge of more than 20 units so far it doesn't mean anything.

No matter - still a nice read!


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## amithrain (Nov 22, 2020)

I fell into the YouTube rabbit hole a few days ago and I feel like these testers still have some variability...

this guy who has absolutely no experience gets a 150 off of an Amazon stone??
For comparison: Ryky is definitely not the best sharpener out there, but honestly, he’s decent enough. apparently he usually gets like 200 off of one of his absurdly long sharpening sessions

and then jef jewell is getting around 80 every sharpening so idk


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## Kawa (Nov 22, 2020)

ModRQC said:


> Well IDK if you made a mistake... I don't even know if you were even replying to me or "in general". I suppose, if you were, you were reacting mostly to the first part of what I said, which was mainly ironic: from 200$ to 600$ I've seen all shades of OOTB edges, from pretty dull to real shaving sharp.
> 
> While on this forum such a thing becomes subjective to nonsensical depths, I think all my J-knives would stand in the largely loose "high end cutlery" category for any given general population.
> 
> ...



The thing is, i guess, many 'new' sharpeners feel that they get better and better with each knife they sharpen. Then there is the phase were some knives end up a little less sharp then the knife you did before. So the steep learning curve starts to flatten, like with every thing you start doing a lot from scratch and put a lot of hours in. Mostly the goal is 'to get the knife as sharp as possible'. But how do you compare? With what others call sharp? subjective. Compare it with your own feeling/memory about a knife you did 2 weeks ago? Not really reliable either.

This sharpeness tester is a nice gimic which you can use to compare yourself with yourself, or with others using the same system. Are those facts? No, not even close. Can you see a measurable difference between sharp en sharper? Yes. 

And then there's the point which many here encounter i guess: *does it matter?* No....

Most in here are at the point that they know when their knife is plenty sharp. Most in here don't even need to try anymore to get the knife as sharp as possible, because thats overkill for the practical use in a kitchen (most of the time). 




I remember a topic about all kinds of strops and what to use. I believe it was one of the masters here (mr. Kippington) that showed me that all you need is cereal cardboard to strop your kitchen knife. Can you have better stropping results? Yes. Do you need it? No. At the same time he said that in the beginning he also tried 100 different strops etc. only to come to the conclusion many years from there, its 'useless'. He even showed us a video from long ago where ye splits a hair with a kitchen knife, telling that he doesn't go that sharp anymore on most knives. (  gimme some of that skill please)
Then you know you are good. All the fancy non-adding stuff makes place for practical solutions. You try to warn newbies for not buying all this nonsence, because soon or later you find out you dont need it and wont use it.

I recognize this, because I'm in the 'newbie' phase for this sharpening hobby, but i'm seeing myself giving the 'Kippington kind of advices' towards newer players in the world of bowling.


I think its part of enthousiasm during a new journey to want to try whatever you hear about. I'm glad most of the time I personally have the strength to listen to the 'Kippingtons' around here. Or I would have had 10 different strops and compounds by now and would have had a 10k, 12k and 30k stone 

But for the eou-sharpeness tester I was weak (mostly because my boss paid for it )
It's like having 10 knifes or 10 stones... It adds something, but it adds nothing


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## ModRQC (Nov 22, 2020)

I don't strop outside that on stones, and have little interest buying higher grits than those 5K I already have. I will surely get one just to see and for the fun of it, but it's like rock bottom on my list. 

At a point where I won't pretend I'm getting better and better with technique for now - it's like you said - I've found that the one thing I could make a more noticeable difference on is how I use the stones I have - trying to maximize their efficiency, getting better edges from the same motions but a stone that's in optimal condition for the steel and job at hand. Finally starting to understand and use the tools better, I guess. IDK I just considered stones so far more like indifferent steps in a progression and focused so much just on improving my technique, but as this became more ingrained, now my focus is getting wider.

I guess trying a lot of coarse hones and doing a lot of thinning in the last couple months helped shifting my attention from my moves towards the behavior and "layers" of each of these stones, and now it's starting to expand to all my stones. Of course this won't last very long - there's only so much things to discover about a stone, and in the end it represents so little compared to skills using them. But it's nice as it gives me something to mull over and keep keen and disillusioned. There will always be something to understand better, and do better, always some small interesting discoveries, and that in the grand scheme of all things sharpening I'm still merely groping in the dark with a much better torchlight is all.


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## Kawa (Nov 22, 2020)

I guess thats what got my attention in sharpening (and bowlingball repairs/polishing = grinding and gritt stuff): the basics seem so little, the plan is so clear. But the longer you practise it, the more you discover.

Easy to learn, hard to master


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## inferno (Nov 28, 2020)

i feel its time for you kawa to sharpen up some knives as good as you can and test them. around 100 on that meter should be possible.


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## Kawa (Nov 28, 2020)

inferno said:


> i feel its time for you kawa to sharpen up some knives as good as you can and test them. around 100 on that meter should be possible.



End of december I have 2 weeks off, then I will take my personal good knives to the stones again. Can't wait.

Yesterday I received this knife for my brother in law who has his birthday in the beginning of december:






Tadafusa Hocho S-43 Koksmes 21 cm


koksmes uit de Tadafusa Hocho S series. Met een unieke bewerking die zorgt voor nog meer snijgemak. Gratis gegraveerd




www.meesterslijpers.nl





I was impressed by the sharpness OOTB, never felt or seen such a keen edge before. It is higly polished, but has so much teeth to it when i drag my nail. It almost has a zero bevel (both sides) with a small microbevel, barely visible (you can see it in the link, the choil picture is the same in real life)
It hit 175 on average after 3 measurements...


I don't think I can achieve anything near 100 yet, but you just gave me a long term goal


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## Michi (Nov 28, 2020)

Being a gadget man, getting one of these testers is tempting. On the other hand, it would be for amusement value more than anything.

When I sharpen my knives, I stop when the edge is "bloody sharp". I don't know where that falls on the BESS scale, but it's sharp enough to shave, and definitely sharp enough for cooking.

But, if you want to pull the trigger, sharpeningsupplies.com currently have a Black Friday Special for the Edge On Up testers.

Just saying'…


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## Kawa (Nov 29, 2020)

Michi said:


> Being a gadget man, getting one of these testers is tempting. On the other hand, it would be for amusement value more than anything.
> 
> *When I sharpen my knives, I stop when the edge is "bloody sharp". I don't know where that falls on the BESS scale*, but it's sharp enough to shave, and definitely sharp enough for cooking.
> 
> ...



Exactly that!

I call my knives sharp after sharpening, u do the same. Probably your knives are way sharper then mine, but I (and I think this goes for most people) don't have anyone in the neighborhood the compare/check where your really stand. Not that it is a competition, but to know if you can (and how much) improve yourself, you first have to know how sharp your sharp really is...
This thing is kinda universal language.


Not to convince you to buy  but I allready found (measured) out that my stropping on leather with red rouge (iron oxide) is not a placebo.
I deburred the best that i can on a shapton pro 2000, meaning till the point Im convinced I dont feel any burr anymore.
Then I measured 3 times.
After stropping the average went down by 80 over 3 measurements.
Ofcourse I know from newspaper test that stropping made my knife slicker and that might be enough to not buy this thing. But if you want to *know*, you have to *know *

Im curious about the results when i overstrop (rounding off the edge). I know when i f#ck up I loose all the grab on my fingernail. 
Haven't dared to overstrop on purpose yet, will happen soon by accident anyway 


It's too soon to buy yourself a Christmass present, but you are allowed to buy yourself a Sinterklaas cadeautje!  (why are these Dutch memes available on this international forum  )


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## Michi (Nov 29, 2020)

Kawa said:


> It's too soon to buy yourself a Christmass present, but you are allowed to buy yourself a Sinterklaas cadeautje!


In Germany, Sankt Nikolaus is 6th December, so that just about works out 

But I just bought myself a PID controller for my smoker, so the sharpness tester will have to take a back seat for a while.


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## Matt Zilliox (Nov 30, 2020)

Toilet paper seems a good measuring tool for murder sharp...


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## M1k3 (Nov 30, 2020)

Matt Zilliox said:


> Toilet paper seems a good measuring tool for murder sharp...


And those that touch other people's knives without asking


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## ModRQC (Nov 30, 2020)

M1k3 said:


> And those that touch other people's knives without asking



Equip your knives with a "Blade" movie-alike security - maximum effect and satisfaction when the infidel gets caught in the act.


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## Jovidah (Nov 30, 2020)

I get a sharpness tester delivered for free in my mailbox every other week. It's called 'the local newspaper'. Works for stropping too.
It's the only reason I haven't put a sticker on my mailbox against unaddressed spam...


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## Kawa (Nov 30, 2020)

Yes that does the job also.

But its harder to tell by newspaper which of your 3 very very very sharp knives is sharper, or
did you actually get the same knife as sharp as you did the last time you did that knife.

Do you need to know? no
If you want to know, newspaper wont do that for you

Its subjective vs objective, as far as you can get objective


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## Jovidah (Nov 30, 2020)

At the point where I'm unable to distinguish the sharpness with a newspaper I'd also consider that to be the point where further sharpening doesn't really bring a whole lot for a kitchen knife. If it's good enough to shave, it's good enough to sever protein and cellulose for me...

There's also a few different ways you can test on newspaper that are easier or more difficult for an edge. But in the end it's debatable how useful any of that is. What's more useful to know is how well it actually cuts what you intend to cut with it. Can you cut onions without crying for example? Can you cut apples and leave them alone without turning brown?
Then there's the whole issue that cutting performance is often more related to what's behind the edge than the edge itself. The finest edge in the world still isn't gonna cut a carrot for crap if it has thick shoulders behind it, just like a mediocre edge can still actually rip through carrots fairly well as long as it's thin enough behind it.

One of the biggest revelations to me was when i finally realized I should be spending more time thinning and less time chasing 'perfect edges'. Well unless you do actually want to shave with it of course.


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## Kawa (Dec 1, 2020)

100% agree with what youre saying.

but.. 

The sharpness tester *only* tells you how sharp your edge is on that point, nothing more. No edge retention, not if its a laser or thick knife, not it it is teethy enough for peppers. So if you want to judge on those aspects after sharpening, we shouldn't even talk about this sharpness tester.

This thing doesnt say 'well, you reached this and this number, now you can cut unions or carrots the way you want'
So it might be that one knife with a score of 100 is very good in cutting carrots, but the other with score 100 does a bad job. It only tells me something about how my edge finish is compared to ---the last time i did this same knife/ other people using the same tester---

Dont use or 'criticize' (or not really doing that) it for things its not intended for,

Next to that, lets not forget that most of you here are way beyond a level that you need, or will benefit from, or _take joy out_ of using a sharpness tester to see how well you did. I bet you dont even need newspaper to test: you probably *know* when you did a good job. If I see little videos of kippington dulling a knife and within 40 seconds he moves through 3 gritts and has the knife razor sharp again... Dont tell me he still needs newspaper or dragging his nail to confirm he is done 


A few around here (including me) are still lesser gods  We are glad when our last knife is being sharpened better then the knife we did before that, which shows improvement.


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## Jovidah (Dec 1, 2020)

If I speak for myself I wouldn't consider myself an expert. Just stuck around here long enough to learn a thing or two from people who do have a clue and applied it enough to realize that what they said made sense. Now I just parrot it so they don't have to type it 38 more times. 
But at some point I reached a level where, at least for me, investing a whole lot more time / effort / resources into it just wasn't bringing me much anymore. The results I achieved sufficed for the intended use. Beyond that I was basically wasting time, or even making things worse (overpolishing is a thing, and can reduce edge retention).

What I normally use is just feeling the burr to know when I reached apex, then Murray Carter's 4-finger sharpness test (just google it, its very simple and surprisingly effective) to get a feel for how sharp something is while sharpening, and then newspaper test to make sure. I think my own most common mistake early on was moving up in grits too soon. If it's not sharp after your mid grit stone, you're not gonna rub it to sharpness on a polishing stone.

Also, don't forget about the fact that some steel types are simply a lot easier / faster to sharpen than others. It's what makes learning / practising on softer stainless so problematic, and it's one of the main reasons so many people swear by carbon knives. Easier to get results, easier to learn with in my opinion.


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