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My knife edge under the microscope (does deburring with cork really work??)

post #1 of 12
Thread Starter 

Hello everyone,

 

So i bought a cheap macro/microscope to see for my self whats happening when im sharpening my knife.

 

As I go through each stage of my sharpening you can slowly see the changes being made to the edge.

 

Please note:

I am no professional at sharpening, im posting on here to see what mistakes i made and gather a bit more insight with you guys

I used a nagura stone on the 8000 grit

I dont own a strop

The knife is a Global 

Sorry for the bombardment of pictures.

 

 

Please use the zoom function, the pictures are a bit small

 

Before sharpening : 

http://imgur.com/xoCChlW    (side)

http://imgur.com/7v0TD24    (edge)

 

1000 Grit:

http://imgur.com/TYp8XFF    (side)

http://imgur.com/mEOY5vx    (burr)

http://imgur.com/DpjZ0X9    (another view of burr)

http://imgur.com/GRiHrmq    ( after deburr )

 

At this point i was confused it seems that deburring with a cork doesnt work ( i used both real and synthetic )

 

4000 Grit:

http://imgur.com/ODKERPT    (side)

http://imgur.com/fjnuAqP    (burr)

http://imgur.com/Dw7DEuO    (after deburring)

 

Again i noticed the "deburring" did nothing to the edge

 

8000 Grit :

 

http://imgur.com/Dw7DEuO    (side)

http://imgur.com/Dw7DEuO    (burr)

http://imgur.com/Dw7DEuO    (after deburring )

 

Then i realised, maybe im suppose to alternate sides when im on such a fine stone so i did

 

8000 Grit alternating after each stroke :

 

http://imgur.com/SvYZ3xR    (side)

http://imgur.com/CsoKP25    (burr???)

http://imgur.com/vEcHMMT    (after deburring)

 

 

Do you think my sharpening is sufficient?

From the pictures is the edge from the 8000 grit how its supposed to look like?

Any criticisms or questions please ask.

 

 

Im trying to improve my sharpening skills, it seems like after a week of prep my knife starts to noticeably dull

post #2 of 12

I used to deburr with cork until I sliced open my hand that way.. Definitely put it down on the board not up in the air with both hands.

 

To me, it looks like you can spend some more time on 1000 grit cleaning up. 

1) sharpen right side, raise a burr on left side

2) sharpen left side, raise a burr on the right side

3) Lighten up on the pressure and do edge trailing (stropping) strokes on this 1k stone.  There's a JKI playlist showing this but using like a J shape motion to catch the tip

 

That removes a lot of the burr more cleanly than a cork which kind of rips it off.  At this point your edge should be pretty good, higher grit stones are just polishing it further and making the scratches smaller

 

Every stone you go up, the pressure needs to be lighter

post #3 of 12
Quote:
Originally Posted by Jasonjjj View Post
I dont own a strop...

 

Im trying to improve my sharpening skills, it seems like after a week of prep my knife starts to noticeably dull

 

Cardboard works good for me as a quickie strop at work and yeah a week of prep will do that. I usually take my knives to the stones once a week, sounds about right to me.

Wisdom comes with age, but sometimes age comes alone.
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Wisdom comes with age, but sometimes age comes alone.
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post #4 of 12
Thread Starter 
Quote:
Originally Posted by cheflayne View Post
 

 

Cardboard works good for me as a quickie strop at work and yeah a week of prep will do that. I usually take my knives to the stones once a week, sounds about right to me.

 

Oh wow that i never knew, i didnt think "hard steel" would take a week to start losing its sharpness, i thought i was the only one whos knifes lost its edge after a week

oh well at least now i know im doing something right

post #5 of 12

I think Global hardens their stainless to 56-58.  This is on the softer side for Japanese knives, probably because they aimed at the western market.  It's soft enough that you can use a ceramic rod without a big risk of chipping

post #6 of 12
Millions is right about staying longer on the first stone. To put it more crudely than he does: you haven't reached the very edge with the lowest stone. First thin until you reach it, than cut a edge in fresh steel.
When you never reached the very edge you're just displacing debris.
Edited by Benuser - 1/4/16 at 3:09pm
post #7 of 12
I should add that with the Globals I don't look for any scratch refinement. Just use higher stones to get rid of the burr, up to some 4k.
But as they come with a convexed edge, solid thinning is imperious before establishing any bevel.
I end them with a 2k microbevel at 30 degree on the right side, just as I do with good old French carbons.
post #8 of 12
Thread Starter 
Quote:
Originally Posted by Benuser View Post

Millions is right about staying longer on the first stone. To put it more crudely than he does: you haven't reached the very edge with the lowest stone. First thin until you reach it, than cut a edge in fresh steel.
When you never reached the very edge you're just displacing debris.
Quote:
Originally Posted by Benuser View Post

I should add that with the Globals I don't look for any scratch refinement. Just use higher stones to get rid of the burr, up to some 4k.
But as they come with a convexed edge, solid thinning is imperious before establishing any bevel.
I end them with a 2k microbevel at 30 degree on the right side, just as I do with good old French carbons.

noted: I need to spend more time on the first stone

Also what is "thinning" ?
and why do I need to do it?

Furthermore I have a deba global, if I used the same technique as I did with this knife how would the results turn out
Do I need to change how I do things with that particular knife
post #9 of 12
Quote:
Originally Posted by Jasonjjj View Post



noted: I need to spend more time on the first stone

Also what is "thinning" ?
and why do I need to do it?

Furthermore I have a deba global, if I used the same technique as I did with this knife how would the results turn out
Do I need to change how I do things with that particular knife

 

Can't tell you about the Global deba. I don't know whether it's a real single bevel.


Thinning is abrading steel at ANY lower angle than the one you will use for the final edge. You thin at that low angle until the very edge is reached, or almost reached. In your case I suggest to go as far as to raise a burr, to make sure all fatigued steel has been removed. If you don't thin performance will decrease after a few sharpenings due to the taper in the blade's geometry.


Edited by Benuser - 1/5/16 at 7:12am
post #10 of 12

http://postimg.org/image/z06xs7jq7/

post #11 of 12
Thread Starter 
Quote:
Originally Posted by Benuser View Post
 

http://postimg.org/image/z06xs7jq7/

 

I see this makes a ton more sense now, is this the reason why it seems that my knifes dont stay sharp for that long anymore?

post #12 of 12
I guess so. When the blade gets thicker you apply more pressure and the impact on the board increases. Expect a very poor edge retention.
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