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

25
10
Joined Jun 5, 2013
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 : 

   (side)

   (edge)

1000 Grit:

   (side)

   (burr)

   (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
 
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2,563
538
Joined Apr 25, 2014
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
 
4,769
1,019
Joined Aug 21, 2004
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.
 
25
10
Joined Jun 5, 2013
 
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
 
2,563
538
Joined Apr 25, 2014
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
 
25
10
Joined Jun 5, 2013
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.

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
 
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