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Removal/Prevention of the Undetectable Micro-Burr

Posted by jasonstone20 
Removal/Prevention of the Undetectable Micro-Burr
August 09, 2016 11:39AM
Other than not creating a burr in the first place, what can be done when sharpening about the small, undetectable by sight and feel, micro-burrs? Especially when they effect performance, which is how I notice them, since I have a hard time finding them with my regular burr detection techniques. I have found that some knives/steels are more prone to this, just like detectable burrs, but it can really hamper getting a very high sharpness level. Maybe it's part of the edge stability formula, I don't know. Cutting off the apex before sharpening helps, maybe jointing the knife before apexing might help:

[youtu.be]

I have found that standard burr minimization, removal, and back sharpening help, along with a pasted strop and minimum passes, but not always.....

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser
Re: Removal/Prevention of the Undetectable Micro-Burr
August 09, 2016 04:37PM
Hi,
How do you notice them, how do they effect performance (you do what, how, and notice what, how)?
What is "jointing the knife" in ten words or less?

____
Thanks
I don't mow smiling smiley
Re: Removal/Prevention of the Undetectable Micro-Burr
August 09, 2016 06:51PM
Quote
ShaperAndMower

What is "jointing the knife" in ten words or less?

Grinding with abrasive perpendicular to the spine to apex line.
Re: Removal/Prevention of the Undetectable Micro-Burr
August 09, 2016 06:55PM
Quote
jasonstone20
Other than not creating a burr in the first place, what can be done when sharpening about the small, undetectable by sight and feel, micro-burrs?

King 1000, or other similar stone.

The biggest problem with abrasives, commonly seen in all the stones are good/bad videos is not realizing that what a stone does, or needs to do, in order to sharpen depends on both the type of steel and exactly what you are trying to do:

-grossly remove metal
-prepare the edge for the apex bevel
-apply the apex bevel

These are the three general stages of sharpening, they each require different properties of an abrasive to work ideally. The second stage with a King 1000 or similar will remove any trace of damage from the apex and leave it in the perfect condition for an apex bevel. The stone setting the apex bevel has to be able to actually cut the steel, not push it around, and do so in minimal passes, again to avoid fatigue.

If this isn't happening then :

-the steel itself is a problem
-you are using a really poor choice of stone
-technique is a problem

You can't do anything about the first one, so you might as well assume it isn't it because if it is you are boned anyway. The second one just requires a little understanding of what is happening in the three stages. Therefor the only real issue is always the last stage.
Re: Removal/Prevention of the Undetectable Micro-Burr
August 09, 2016 07:51PM
ShaperAndMower,
You can notice them by the knife being hair-popping/tree-topping shaving in one direction, while only scrape shaving in the other, and/or not push cutting phonebook paper on a 3x90°. Jointing the edge is like distressing the edge/cutting off the apex, you lightly cut into the stone in perpendicular motion, usually right before apexing the knife.

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser
Re: Removal/Prevention of the Undetectable Micro-Burr
August 09, 2016 08:00PM
Cliff,
Thank you. The King 1k and similar muddy stones has been the only way I have been able to minimize this effect, sometimes with deburring and burr minimization also for good luck when I am having real difficulties. I have been reading Jeff Clarks's posts on Bladeforums threads about this topic also from the early 2000's:

[www.bladeforums.com]!!!!

[www.bladeforums.com]

Interesting to see your contributions there also, I miss the old Bladeforums.

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser
Re: Removal/Prevention of the Undetectable Micro-Burr
August 09, 2016 08:12PM
And this thread also, a longer one:

[www.bladeforums.com]

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser
Re: Removal/Prevention of the Undetectable Micro-Burr
August 09, 2016 09:55PM
Thank you guys

I didn't think to check but even wikipedia has entry for Jointing (sharpening)

Basically its like de-re-curving grinning smiley stefanwolf88 style (saw stone)

Regarding this invisible burr
Usually when I can push cut with grain only (after backsharpening )
I assume invisible burr (after backsharpening a few more passes)
because a rare few times I've been able to stand it up by stropping
on paper and do a push cut cross grain

So my method has become raise burr,
deburr,/backsharpen / check for 90 push cut,
and repeat until I can push cut at 90

After that I try to force bias and degrade push cutting,
by cutting into piece of wood, plastic bottle
and strop on paper (wrapped around pen/marker)
at high angle of ~45 degrees
to try to force a bias to one side,
that should degrade push cutting ability
enough to detect by push cutting paper





I've also watched this shapton video,
and the guy flat out says what I've come to suspect over the past two months,
when a lot of people say toothy, they really mean tiny burr
because they're not double angle deburring between stones,
coming off 1k stone or even higher, and even strops,
then barely feeling the edge with fingertips and saying it feels toothy
this guy says that after 16000 and 30000 stone
but also says its a burr and shows microscope picture
..
I can barely feel any "tooth" after my 600 grit harbor freight diamond
if its real easy to feel it has to be burr and has to be reflective

FWIW to figure out push cutting
what I did around march is take two utility razor blades (plain carbon)
put a split stick handle on it,
so there is more edge exposed than usual,
and then practice sharpening a few times every day
and practice 90-90-90 push cut with both blades
as most of my other practice blades have tapers (some still do)
so I was always doubting the angle
and slicing too much


Its basically magnified a few minor issues I've been happy to ignore
but that have been holding back from figuring out push cutting
and figuring out how much deburring and backsharpening I needed

things like not making contact with all of the stone
as the blade is tilted, tip either digging in or floating in air
flexing the blade by pressing too hard
and developing recurve (double )
so when deburring/microbeveling not hitting some (two) parts of the edge and
unless I tilt blade so its only touching corner of the stone
rocking / wobbling to put too much (fat) convexity

Its nothing I didn't observe and forget about often over the year before grinning smiley

____
Thanks
I don't mow smiling smiley
Re: Removal/Prevention of the Undetectable Micro-Burr
August 10, 2016 06:20PM
Jason,

In my experience you basically have three choices:

1) Keep trying to cut-off the burr and backing out the tiny additional bevel without recreating the burr. This applies if the issue occurs or is discovered at the apex setting stage with non-friable abrasives.

2) Use a muddy ~4k-6k waterstone to make the microburr so small that, even if it persists, it isn't big enough to affect performance. This is basically why I will spend some time on a ~4k-6k waterstone after a 1k prior to setting the apex if I am aiming for extremely high push cutting sharpness.

3) My experience with coarse particulate abrasive (10+ micron) stropping is that they have little trouble removing any burr small enough to not be detectable without a microscope, but my experience is coloured by most of my knives having their edge bevels shaped on muddy waterstones prior to apex setting. I'm not sure what the maximum scale of micro-burr that they would be able to remove is.
Re: Removal/Prevention of the Undetectable Micro-Burr
August 10, 2016 06:31PM
Steel_Drake,
Thank you. That's usually what I do, I just really wasn't sure if I was missing something, so I thought I'd ask.

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser
Re: Removal/Prevention of the Undetectable Micro-Burr
November 05, 2017 08:55PM
I have found that stropping, with or without abrasive can help remove the microburr, but not always. When stropping doesn't work, I have found that slicing into soft wood and then microbeveling helps get rid of the microburr.

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser
Re: Removal/Prevention of the Undetectable Micro-Burr
December 05, 2017 09:56AM
Has anyone found a good, reliable test to see if a mirco-burr is present? I have found that a edge with a fine, small, hard to detect burr can whittle hair in both directions (root to tip, tip to root), sometimes just as easy as a clean edge. How can the hair whittling or Hanging Hair Test (HHT) be more reliable? Try whittling from both directions (left and right) on the blade, just like you would testing for a burr with a shaving edge(make sure it shaves in both directions)?

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser
Re: Removal/Prevention of the Undetectable Micro-Burr
January 11, 2018 10:43AM
I had been looking for this video for some time:
[youtu.be]

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser
Re: Removal/Prevention of the Undetectable Micro-Burr
March 23, 2018 08:25AM
I think a lot of the cause of micro-burrs is that the steel is either damaged or fatigued. I almost never have an issue with micro-burrs once I get to undamaged, fresh steel.

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser
Re: Removal/Prevention of the Undetectable Micro-Burr
September 24, 2018 10:58AM
Interesting thread on removal of the wire-edge/micro-burr:


[www.bessex.com]

This part describes the technique by the Knife Grinders:
[quote="Knife Grinders]
*************************************************

WIRE EDGE PREVENTION
I've seen several ways to successfully clean the apex of the micro-burr:

1) By honing at the edge angle, the base burr can be honed away on steels that are not prone to produce a secondary burr by burnishing from honing - I've seen it on A2 and D2 tool steel and quality kitchen knife brands, typical of Japanese kitchen knives.

2) By higher-angle honing.
- For high-end and tool steels it is by 0.4 - 1 degree higher than the edge angle;
- For mainstream steels it is by 1.2 - 1.6 degree higher than the edge angle;
- For lower-end steels it is by 2 degrees higher than the edge angle.

Before you go to any of these honing modes, you have to thin away the bulk of the burr to expose the base "mother burr". That's why I say that the proper deburring requires minimum 2 steps. Let me detail how I do each mode.

Honing mode 1) at the edge angle
I set 2 honing wheels - one at a shallower than the edge angle, by 0.1 - 0.3 degree less (e.g. a 15 dps edge will be honed at 14.7 - 14.9 dps), and the second wheel at the exact edge angle.
The first shallow honing wheel is thinning away the bulk of the burr, and has a 3-6 micron honing substrate.
The 2nd wheel is honing away the base burr to the clean apex, and has 0.5 micron honing substrate.
In the process of honing I may move the blade between these 2 wheels several times, each time checking sharpness on the tester.

I use the honing mode 1) when asked to sharpen a knife to the "bragging rights" utmost sharpness. Typical sharpness score is 25-50 BESS, sometimes 15-20 BESS - i.e. that of a DE razor or sharper.

Honing mode 2) at a higher angle
I set 2 honing wheels - one at the exact edge angle, it will hone away the bulk of the burr with a 3-6 micron honing substrate; and the second at 0.4 - 2 degree higher angle depending on the steel as specified above (e.g. a 15 dps edge will be honed at 15.4 - 17 dps), it will hone away the base burr and has 1-micron honing substrate.

I use the honing mode 2) for the majority of practical edges. Typical sharpness score is 55-90 BESS.

The finishing step includes gentle swipes on a clean leather, or a nano-cloth hone or a paper wheel with <=0.25 micron honing agent, at the exact edge angle or a slightly higher angle up to 0.5 degree higher than the edge angle.
[knifeGrinders.com.au]
[/quote]

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser



Edited 1 time(s). Last edit at 09/24/2018 11:08AM by jasonstone20.
Re: Removal/Prevention of the Undetectable Micro-Burr
November 08, 2018 01:45AM
New information from KnifeGrinders:
PDF:
[knifegrinders.com.au]

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser
JDW
Re: Removal/Prevention of the Undetectable Micro-Burr
November 10, 2018 12:40AM
Thanks for posting! A lot of information there. I will have a look at it.
Re: Removal/Prevention of the Undetectable Micro-Burr
July 24, 2019 10:31AM
Blade Forums -- How To -- Really Detect Micro-Burr

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser
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