So how sharp is super sharp Freehand?

R

rm41400

Joined
Dec 11, 2020
Messages
62
Title says it all…
ON POCKET KNIFES :)

I can chop thin standing paper with my Japanese kitchen knifes but they have really low angles 12-15*??

On my pocket knifes I just can’t get that sharp…

I guess I was expecting I could get there on a pocket knife freehand but with my method it’s really hard to get there and not reliable.

Is this a reasonable level of sharp or just not worth the fuss?
 
The lower angles are the difference. On a pocket knife with more obtuse angles it is a lot harder to get that sort of sharpness. Plus it is a more of a work tool, that is what they were designed for and sometimes we have unrealistic expectations, i posted this in another thread, but i just finished giving this a touch up. 17 degrees at aprox 4000 grit, and it is as sharp as you will need any knife. Slices packing foam pellets into thin slices easily, that is a great test of sharpness, it will take a strip of arm hair effortlessly, but that way of checking for sharpness is unsustainable, you will eventually run out of hair, plus it looks ridiculous. :oops::rolleyes::).

e5HJytq.jpg

Vz3aKjG.jpg
 
Hello. I don't claim great sharpening skills. But, I've free hand sharpened all my life. There is skill involved and "muscle memory" if you will. You just develop a feel.
A lot depends on your abrasives and progression from coarser to fine. Having set good bevels with good apex.
Good edge geometry is important as well as good heat treatment (fine grain).
My current test of sharpness is folding phone book paper, standing it up, placing the blade edge with just the apex in contact and pressing straight down. If it breaks the tension and push cuts through, that is my "sharp".
***Please understand I don't achieve the best sharpness by far. I've seen blades just touch a hair and the hair pop apart!! Or, place a blade edge up and drop a piece of paper and the paper split!!
Lol, I still can't cut a free hanging hair, as much as I've tried.
 
cudgee said:
it will take a strip of arm hair effortlessly, but that way of checking for sharpness is unsustainable, you will eventually run out of hair, plus it looks ridiculous
Click to expand...

Haha, if done like YouTubers who have a compulsive need to show a four square mile section of bare arm, then yes. When I do it, it's usually only a single arm hair at a time, usually on my wrist, and for my own knowledge, rather than for show. Three separate hair shaving tests usually does it for testing an edge, somewhere around the heel, the middle and the tip. And then if the knife slices paper cleanly, with the right sound, and no snags along the length of the edge, I know that sharpness is consistent heel to tip. That's what I try and shoot for.
 
Most of 'sharp' is about making the apex as crisp, complete and narrow as possible. The apex width of extremely sharp shaving edges, such as on straight razors, will often be down to a few tenths of a micron, maybe 0.3 micron or even narrower.

And then, assuming the apex is good, the rest of cutting gets progressively easier as the edge geometry gets narrower in angle. Edge angles at/below 30° inclusive will start to show big improvements in cutting. And it gets really good once you're down to maybe 25° inclusive or less. Below that, it becomes about whether the steel itself can remain strong enough to hold such a thin edge. Below a certain point, even the best of shaving-sharp edges become essentially moot if the steel can't hold the edge - you're basically shaving with a weak burr at that point, and one cut into anything 'normal', besides clipping a hair, and the same level of shaving sharpness will go away in a heartbeat. Even slicing into paper can erase shaving sharpness, if the steel isn't strong enough to hold it.

For EDC pocketknives, I've found that most any steel at decent hardness (HRC 55 or better) can hold a 25° inclusive edge pretty decently in most typical, non-abusive cutting tasks. I sharpen all my knives' edges to this ballpark, after which they should be able to slice cleanly and smoothly through phonebook pages (or catalog, magazine or newsprint) without slipping or snagging. If they handle that well, I call it good. Sometimes they'll shave too, or tree-top hairs from my forearm. If it does, that's gravy. But I know such sharpness is fleeting and won't last in normal usage. So I don't aim for that, per se.
 
Last edited:
I typically sharpen folding knives to about 15° per side, or 30 inclusive. Even with that you usually end up with pretty wide bevels. Some folks don't like that. I don't hate it, but I would definitely prefer knife makers to make their blades thinner behind the edge. And more hollow grinds, please.

As far as "what is sharp" goes, I use a BESS tester. I consider anything below 135 sharp, and anything below 100 very sharp. I can usually get pocket knives to around 100 free handing. It's interesting, at least to me, that the more convex free-hand edge seems to slice paper better than a fixed angle edge that tests 20-30 points lower on the BESS tester. But the BESS score correlates better to shaving and tree topping sharpness. I guess the sharp bevel from a fixed angle system creates more drag when cutting paper.
 
cleanly cutting toilet paper. paper towel is pretty tough too. I found that, if a pocket knife isnt slicing these materials cleanly and easily it's either 1) dull or 2) the edge is at too high of an angle. Any of my knives around 34* or less can cleanly cut paper towel and toilet paper. Above that, maybe, but over 38* its almost a hard will not cut well.

Also depends on the stock thickness and primary grind. My Hinderer XM-18, I think I have it at 34-36* inclusive, but I wouldn't go any lower than that probably because the bevel width is MASSIVE. But it cuts well, for sure! A thinner blade, like a Spyderco Police, that thing is almost cheating...LOL
 
Sharp in my opinion means it is able to do the task you want it to do. If your purpose is to.whittle.hair then that's your benchmark. For me 1200 dmt is plenty sharp for what I need. And my kitchen I do a 325 dmt one and done.
 
I did a test one time and sharpened one of my knives to where it would whittle hair. I then took the knife and made cuts about 6 inches long into a normal piece of printing paper and retested the sharpness of the knife every 5 cuts. I could still whittle hair I plucked from my head after about 20 six inch cuts but, that scary sharp edge went away after that. If your cutting cardboard or any kinda of normal EDC task your knife isn't going to stay crazy sharp for too long. Other than bragging rights and to feel like a samurai it really doesn't serve much purpose. If you can slice horizontal phone book paper cleanly your good to go. Anything past that wont last.
 
Last edited:
cudgee said:
The lower angles are the difference. On a pocket knife with more obtuse angles it is a lot harder to get that sort of sharpness. Plus it is a more of a work tool, that is what they were designed for and sometimes we have unrealistic expectations, i posted this in another thread, but i just finished giving this a touch up. 17 degrees at aprox 4000 grit, and it is as sharp as you will need any knife. Slices packing foam pellets into thin slices easily, that is a great test of sharpness, it will take a strip of arm hair effortlessly, but that way of checking for sharpness is unsustainable, you will eventually run out of hair, plus it looks ridiculous. :oops::rolleyes::).

e5HJytq.jpg

Vz3aKjG.jpg
Click to expand...
Run out of hair? Well yes..
Looks ridiculous...I'll have you know Sir, it's called Knifemakers Mange and it is a genuine condition that effects millions of makers, collectors and even casual knife enthusiasts. The patchy,stubbly, results are noticable to many and can make the afllicted feel self concious.
So be kind to those who suffer.
 
elasmonut said:
Run out of hair? Well yes..
Looks ridiculous...I'll have you know Sir, it's called Knifemakers Mange and it is a genuine condition that effects millions of makers, collectors and even casual knife enthusiasts. The patchy,stubbly, results are noticable to many and can make the afllicted feel self concious.
So be kind to those who suffer.
Click to expand...
I've taken everything you have said on board dear sir, but it is treatable, you just have to reach out for help.🤝❤️❤️❤️
 
Hello. Update related to a few of my recent posts in a few threads. I recently purchased a Belgian Blue and Coticule whetstone.
I've been trying to improve my sharpening and honing skills for a while now, but never gotten the hanging hair test keenness.
I started to watch some straight razor honing vids on YouTube and pad attention on some of their techniques.
In the last week I sharpened and honed 2 different knives to split free hanging hair.
I freehand sharpen, so I've had to develop improved fine motor skills.
What has helped me:
- take time and good abrasive to "set your bevel"
- work with a knife with good qualities; grinds, heat treatment, etc
- get the abrasives you need to progress through edge bevel refinement
- go slow and light; check bevel angle and alignment frequently
- finish with light and careful stropping; again check angle and alignment
- check edge/apex every few passes; I was going too fast, too much pressure, too many passes
I knew I was getting close when I could lightly put edge onto toilet paper and easily slice with just weight of the blade.
*** As they say, "YMMV". For me, the strange thing is that while I think it is cool to achieve that level of sharpness and "skills", it makes absolutely no practical difference in my use of my knives, LOL.
Best regards and God bless
 
You must log in or register to reply here.
Back
Top