Honing steels, just don't (or not)

[eveled]

I never bought that whole realigned edge idea. But steels will remove a little metal. Basically a really fine finishing step. It is basically a fine file with the teeth running longitudinally. You are dragging the edge across the file.

I’ve seen too many kitchen knives turned into kukris because they were only sharpened on a steel to believe they don’t remove metal.

The blade on my fathers SAK is half worn away and all he ever used on it was the little steel that came in the sheath.

 

[roaduck]

If you haven`t got a junk drawer - you`re OCD, busy or otherwise engaged - and I have improved - honestly _ An old dog can learn new tricks - deffo.

 

[beeinak]

I enjoy watching the butchers at my favorite shop carve through meat. It appears to me that they follow the same general sense as chain sawyers- sharpen it before it is dull.

 

[roaduck]

All blades are serrated - even on a microscopic level - or they wouldn`t cut - it`s just a question of a degree.
I just use a cheap caidao for 90kg a day of produce - there`s a lot of hungry in the winter - so so sad.
I do dinner parties to get more help - life is insane.

 

[Mr.Wizard]

All blades are serrated - even on a microscopic level - or they wouldn`t cut - it`s just a question of a degree.

We can argue about the antecedent all the way down to atoms I suppose, but the conclusion "or they wouldn't cut" is simply not true. Fundamentally a sharp edge acts to concentrate force into a tiny area of pressure sufficient to overcome the strength of the material being cut. No serrations or other irregularity are necessary for this, though irregularity can further increase point pressure and introduces the mechanism of mechanical keying.

 

[roaduck]

This is just my anecdotal experience but I have seen an edge with a USB 120x microscope and when the tiny serrations wear down - it`s like using a butter knife.
Like this for example -
Razor blade magnified
Here is a straight razor edge done with a Shapton 15000 at 3000X magnification with the burr removed.

 

[Guy McVer]

If you haven`t got a junk drawer - you`re OCD, busy or otherwise engaged

Or if you're like me, then everywhere is the junk drawer.

 

[roaduck]

Yep Guy McVer I am not mega tidy nowadays because of my arthritis etc but I was a bit OCD as a kid.
Then, when I was about twelve years old I grew out of it because it was wasting my life and taking too much time up.
You can overdo anything can`t you ?

 

[Mr.Wizard]

This is just my anecdotal experience but I have seen an edge with a USB 120x microscope and when the tiny serrations wear down - it`s like using a butter knife.

As I often do I'll refer to the work of Todd Simpson on his scienceofsharp blog. I think in the case of shaving, tooth is counterproductive.

Here is an SEM image of the edge of Feather razor blade.

"Side view SEM image at 5kX magnification following the stropping progression."

 

[Cementite]

Or if you're like me, then everywhere is the junk drawer.

I never lose anything, because everything is always all in the same heap!

 

[Kbrasmodeler]

As I often do I'll refer to the work of Todd Simpson on his scienceofsharp blog. I think in the case of shaving, tooth is counterproductive.

Here is an SEM image of the edge of Feather razor blade.

"Side view SEM image at 5kX magnification following the stropping progression."

No micro-serrations? Then it cannot shave the way it does. It's anecdotally impossible.

 

[roaduck]

It`s not totally flat but I stand corrected Mr. Wizard and Cementite.
Thanks for the vote of confidence Kbrasmodeler .
Shall we just agree to disagree like in a Classical Greek philosophy engagement ?
Next time I am going to get an insanely sharp axe out of the shed at HRC 52 and get my beard off.
I am not taking the piss, i am simply pointing out that it is simply "pointless" and does not hold an edge.
Oh by the way I have forged 700 knives since 1979 in Blackburn and Wetherby UK and lived upstairs in a forge for five years where I made a lot of carbon sickles, axes and hatchets for Yorkshire farmers that wanted to get fit and freaky save the Whale girls from Haugsund, Norway (where I lived) and Hull, North Yorkshire.
I lived in a forge in the centre of the village - no running away from that - Kirk Deighton - about 13 miles to Leeds.
Went to Grammar school in Knaresborough on the river Nidd and met tens of blacksmiths before 1980.
Then I got an OND and HND in metallurgy, metalwork and welding including pattern welding.
My main book was from 1880`s - English blacksmith - name escapes me.
Then, as a hobby in Hong Kong and Macau, China I forged mostly Asian knives, sickles axes and hatchets in mainly Aogami #2 and Shirogami # 1 hitachi billets but I also made steel from iron sand after 15 years when my reject rate went below 5% in a 150 year old forge with no electricity - I am not kidding - but I am still learning and did about 100 stainless and semi-stainless "sharpies"
I had to learn differential hardening - I had no choice.It took me over 15 years to learn.
My Mecanese was terrible.
I am definitely broad-minded and will consider alternative points of view.
I have been a systems analyst since 1980 for ICL computers and international sales rep for Sugden in Heckmondwike selling Hi-Fi`s in 62 Countries, Lived in ten Countries had 4 passports plus I have two degrees in phytopharmacology and parapolitics in Exeter and Preston respectively from the mid eighties.
And I still feel stupid - the subjects are huge.
Oh I forgot to mention I have family in Guangzhou and have connections in my Manchester - Chinatown Chamber of Commerce so I have my finger on the pulse plus the
ir access to CATRA labs in Sheffield etc plus the uni there and applied industrial sponsored projects therein in conjunction with RIO material sciences - Hallum they are having a post industrial renaissance.
This is the shadow of the invention of stainless steel and crucible steel Worldwide and the university/industry collaborations even since the last quarter of a Century.
I have a friend just down the road from me that has a postgraduate advanced metallurgy MMet and he leaves me standing.
I only got into blacksmithing to de-stress from a high pressure sales job and integrate into China.
It was ironic that my cousin did not know I lived in China for nearly 20 years because we were out of touch for nearly 20 years and have only recently got reacquainted - I just went there on business doing exhibitions for three days so I hardly knew anything initially.

 

[roaduck]

I`ve only made about two dozen sickles and knives since about 1998 - I have avascuslar-osteo-necrosis - AVN which is like arthritis with knobs on and it`s dead frustrating - I have had to relinquish my driving licencse etc.
I gave my BMW away because I wasn`t fit to drive.
I`d love to get into a forge again but health and safety regulations won`t allow me no matter what.
I wonder if rules will be relaxed somewhat when the SHTF.
Oh another thing, because I never had a bean when I was younger and learnt to do anything with a caidao in China - small and budget knives don`t faze me anymore.
I only have a handful of decent Asian knives - out of loads.
I learnt to sharpen on rocks outside and walls, floors and bottom of plates - no choice whatsoever.
You may ask where photographs are - on a bridge camera that got stolen in 2010 and on 35mm that I have not got developed yet because it shows ghosts of my dead Mother and war pictures from the Middle East I don`t want to see or remember again - they`re upstairs forever.

 

[roaduck]

As I often do I'll refer to the work of Todd Simpson on his scienceofsharp blog. I think in the case of shaving, tooth is counterproductive.

Here is an SEM image of the edge of Feather razor blade.

"Side view SEM image at 5kX magnification following the stropping progression."

I don`t dispute those photos but at the time they were $55 an hour to set up a long time ago and I don`t believe they`re typical - just my opinion.
They are still not perfectly flat are they and no doubt further magnification will reveal even more irregularities.
This is not just my findings and a cursory glance at science of sharp did not persuade me or alter my initial conclusions before I had access to the relevant scanning electron microsopy results.
Is it perfectly flat ? - No. Why ? What is the relevance ?
Nearly straight with microscopic shoulders is not perfectly flat is it? and that`s just at 50000x - lets move the goalposts and go to half a million magnification - I think that`ll be slightly revealing but too expensive to show - especially nowadays.
In a word - microscopic saw - I rest my case.

 

[chalby]

I don`t dispute those photos but at the time they were $55 an hour to set up a long time ago and I don`t believe they`re typical - just my opinion.
They are still not perfectly flat are they and no doubt further magnification will reveal even more irregularities.
This is not just my findings and a cursory glance at science of sharp did nor persuade me or alter my initial conclusions before I had access to the relevant scanning electron microsopy results.
Is it perfectly flat ? - No.

Believe what you want to believe but the point is it isn't the presence of serrations (no matter how small) that creates a keen edge. As Mr. Wizard said it is a matter pressure vs surface tension simplistically speaking. I would recommend reading all of the articles and studying the SEM pics on scienceofsharp to gain a better understanding, but plainly speaking it is about the apex width not the level of unevenness. Unevenness can create conditions where an edge can perform better and last longer but the cutting ability of an edge doesn't rely on that unevenness.

 

[roaduck]

That edge is neither uniform or typical.

 

[roaduck]

Flat means no irregularities whatsoever at any magnification.

Do you want a see a flat profile cutting ability vs a slightly serrated profile?

Only obsidian can get flatter but is too brittle to use under half to one micron which is the lowest stable apex available.

Here`s with a typical knife edge - not a common kitchen knife in the low hundreds if you`re lucky.

If the edge has any tiny serrations whatsoever - it is not perfectly flat is it ? Nope - Never - Unobtainable - simple as that.
Even a single third of a micron deep furrow or even a tenth of that in a ten inch blade is technically a serration.
Most, if not all apexes are a micron wide - please furnish me with results to disprove that statement or they are not stable.
The more serrations present - the better the cutting ability - why is that ?
These last three videos are attributed to a bladesmith and I don`t think he`d be shifting many knives if he didn`t know his onions.
Here`s a question for you - Why do blades that are flatter with less irregularities underperform in real-World cutting conditions compared to a new blade or freshly sharpened blade ?
It is a simple physics formulae -pressure equals - force divided by area - ergo a wide perfectly flat blade imparts less pressure than a microscope point irregularity on any given blade - that is uncontestable.
Oh yes also a smooth worn-out flat blade does not cut as well as a blade with micro-serrations and irregularities - that is scientifically proven.
Oh another thing - I would like to see a video of the lovely flat SEM blade cutting anything compared to a new or freshly sharpened blade.
It will do it but not accomplish it as well so it is not as efficient is it ?
Why is that ? P=F/A - even at and especially at a microscopic level.
In a word - Physics - Blade geometry and steel hardness is a secondary consideration even if the steel is soft with negligible edge retention - it only has to prove the point once to elucidate the inescapable observation and resultant conclusion.

 

[chalby]

Flat means no irregularities whatsoever at any magnification.

Do you want a see a flat profile cutting ability vs a slightly serrated profile?

Only obsidian can get flatter but is too brittle to use under half to one micron which is the lowest stable apex available.

Here`s with a typical knife edge - not a common kitchen knife in the low hundreds if you`re lucky.

If the edge has any tiny serrations whatsoever - it is not perfectly flat is it ? Nope - Never - Unobtainable - simple as that.

OK, but the "tiny serrations" are not what enables a cutting edge. The width of the apex does.

 

[Guy McVer]

I don't know anymore!

There's no such thing as perfectly flat. There's no such thing as a perfect apex. Circles don't exist in nature. Planet Earth is an oblate spheroid. Help me, Plato! Did Socrates really even exist?

What is a man? A miserable little pile of secrets. But enough talk...

Okay how am I supposed to fight Dracula if my edge is pixels. Is that good or bad? And how does a honing steel affect 2D squares?

 

[chalby]

....Most, if not all apexes are a micron wide - please furnish me with results to disprove that statement or they are not stable.....

Again I would recommend having a good read and look at the images at scienceofsharp.com.

The image from that site that Mr.Wizard provided shows that the width of the apex is a lot smaller than 1 micron. A 1 micron apex would be what most would consider dull.