Freehand sharpen fixing a kitchen knife with 3mm damaged edge and tip

[BluntCut MetalWorks]

Fix a heavily damaged kitchen knife. Not really a best use of time to fix a $3 knife. Oh well, got it done using a $3 & $3.5 Aluminum Oxide stones - est grit 60 to 220.

Thanks for watching.

[video=youtube_share;ZEqRVrKrtH8]http://youtu.be/ZEqRVrKrtH8[/video]

note: For this video, I used a belt sander to turned the edge deformations into big chips so you can see the extend of the edge damages.

 

[xuz]

Thanks for the vid!
I found it to be educational.
Always nice to see someone working his magic with AlOx.

 

[Magnaminous_G]

Very nice stone work, Blunt. Especially the way you reformed that belly. Beautiful! :thumbup::thumbup:

 

[BluntCut MetalWorks]

Thanks xuz & Mag!

Calling sharpening experts. How do I sharpen a knife using a spherical rock (or any abrasive on a hard spherical shape stone/backing)? Yeah some of my friends are smarty - did a Pai Mei on me. I didn't accept but could be fun doing, need to learn a few fu-moves...

 

[Jason B.]

A rounded stone is used for convex edges, wouldn't work too well for a small standard bevel.

One recommendation if I may, start by grinding the edge at 90 degrees to the stone. This will remove the damage faster and give you better control of the blade curve. Sharpening out damage can cause distortion in the bevel as different sections grind faster than others.

 

[BluntCut MetalWorks]

A rounded stone is used for convex edges, wouldn't work too well for a small standard bevel.

Are you thinking rounded stone-edge for recurve edges? To be clear, I am refering to a stone shape like a tenis ball. When sharpening on a flat surface the contact area between stone & blade bevel = a 2 dimensional intersection / a plane. Sharpening against a rod, intersection = a line. Against a ball/spherical, interaction = 1 point (ok, not exactly a point but a very circle small area with un-even pressure).

One recommendation if I may, start by grinding the edge at 90 degrees to the stone. This will remove the damage faster and give you better control of the blade curve. Sharpening out damage can cause distortion in the bevel as different sections grind faster than others.

Thanks, I agree 90* give better curve/profile control but the downside of 90* is the edge skip & gash the stone/plate/belt. So lately I mostly do 45 to 75 degree instead.

 

[Jason B.]

It's very similar to how sword polishers round the end of their stone for sharpening. Typically reserved for large bevel faces. Technically speaking, you only ever contact one small area when sharpening you just don't really notice it until using finer grits.

When going 90 to the stone its best to use the side of the stone if large enough. You don't move it side to side like sharpening but front to back like cutting rope.

 

[BluntCut MetalWorks]

Jason/Knifenut1013 - yours feedbacks/advices are well appreciated.

It's very similar to how sword polishers round the end of their stone for sharpening. Typically reserved for large bevel faces. Technically speaking, you only ever contact one small area when sharpening you just don't really notice it until using finer grits.

Sword polishing is another art & sharpening realm - nifty cool alright. My googling-fu is weak, so only see Hadori - Whitening Hamon resembling use of ball-shape sharpening stone for hamon on the blade face. If you don't mind, please spoon feed me a few link for sharpening. Sure, I'll quickly give up if it will take me more than a few days to learn the techniques.

When going 90 to the stone its best to use the side of the stone if large enough. You don't move it side to side like sharpening but front to back like cutting rope.

my 140 diamond plate (CKTG) got quite dulled - or is it broke in? - grinded this way when fixing a Tojiro clad knife (4mm chip from coconut). Hogging metal on a belt is mostly 90* anyway however I can feel ceramics fly off the belt into my face & goggle. So I cheap out to save belt and doing it at 75* for hardened steel.

 

[Jason B.]

http://www.youtube.com/watch?v=-B7ACeHvSSM

In the beginning of this video its easy to see.

I would recommend watching all three parts.

Diamond plate would be the wrong tool for the job, I use a Nubatama 60 grit or other coarse bonded abrasive stones.

 

[BluntCut MetalWorks]

http://www.youtube.com/watch?v=-B7ACeHvSSM
In the beginning of this video its easy to see.

I watched part 1 and re-watched the beginning a couple time. The stone he used is curve at one end, which can be consider/envision it as chunk/section of a big cylindrical stone/wheel. Also I noticed in his assorted of whetstones, nothing resemblance a tenis/soccer ball shape stone. Maybe that no one out there have that much spare time to nutty attempt at sharpening a knife using an abrasive ball (contact point size of a needle).

 

[Jason B.]

The way their sharpening stand sits allows just the end of the stone to be used and each polisher will apply their desired amount of curve. A actual abrasive ball would be a waste of good skill

 

[xuz]

It would be quite interesting to see/hear your results on your sharpening with a ball.

knifenut is on the balls that Japanese have mastered the convexed stone grinding.
Around 1992, I had the pleasure of visiting Japan and attempting to sharpen/polish a wakizashi the traditional way.
The video posted by knifenut is pretty much it. They use dressing stone to convex their stone (toishi) then very slowly and meticulously grind the blade surface one point at a time.

Before that, I used to swipe my blade when profiling, as that seemed to give me more even exposures through the entire length of the blade. After coming home, I tried to learn their "one point contact" method, and it has opened up a new world for me. The result is something like this:

(Photo from unknown source.)
When you can grind a perfect convex into a bowie or your pocket knife using this method,
there is quite a large sense of accomplishment.

But I completely realize what you are saying about "contact point size of a needle". That seems to be a challenge, entirely in its own class. Good luck and let me know how it goes. It may open up a new world for me again!

 

[BluntCut MetalWorks]

Tee up a SiC Titleist 4, a dull 15N20 petty wedge on hand ... find island green (slice phonebook paper) or water (dull)?