Sharpness tester

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peterng

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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
 
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?
 
Bensbites said:
Can you get a $20 milligram scale and come up with your own system?
Click to expand...
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.
 
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?
Click to expand...
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
 
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.
 
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.
 
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.
Click to expand...
I'll take 2!
 
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.
 
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.
 
Last edited:
.. 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!
 
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.
 
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.
Click to expand...

"Sharp AF" is not a technical term, according to the list. Perhaps you meant to say "nuts sharp" or "insane sharp".
 
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 🤷‍♂️).
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!
Click to expand...

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.
 
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.
 
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.
 
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!
 
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
 
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.

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!
Click to expand...

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. ( :oops: 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 o_O

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