Yanagiba sharpening Problem

[da_mich*]

Hello,

I've been sharpening knives for several years now but i have much problems with yanagibas. Most times i get some high/low spots at the bevel. How can i fix this spots? I tryed a #400 grit stone for one hour but it won´t work.
Maybe anybody has a good tip for me. Thank you very much



Best Regards,
Michael

 

[Caleb Cox]

120 grit sandpaper taped to a flat surface, if you have major metal to move. This exercise really hammered home the "value" of the inexpensive yanagiba I bought as my first single bevel knife (low spots and an improper bevel).

 

[M1k3]

Like above suggestion or a lower grit stone. Something 120-220ish. Shapton 120 Pro/Kuromaku or Sigma Select 120 be my suggestion. They stay flat. You may need to refresh the surface occasionally though.

 

[Barclid]

Jesus Christ that's an intense low. The edge doesn't look straight either. Have you checked whether the knife is warped?

If that were mine I'd chuck it and get one that's not so massively ****ed.

 

[da_mich*]

Thank you very much, maybe i try a #120 grit sandpaper mounted to a sander tomorrow. I have very nice experiences with this method to mirror finish blades (I posted a tutorial for this method a few months ago). Maybe it will work for sharpening yanagibas too. My yanagiba from the picture is a cheap knife. If it goes wrong it is not so bad, its a experiment.

Link for the sander mirror finish method:
https://www.kitchenknifeforums.com/threads/before-after-restauration.43032/

 

[da_mich*]

Jesus Christ that's an intense low. The edge doesn't look straight either. Have you checked whether the knife is warped?

If that were mine I'd chuck it and get one that's not so massively ****ed.

It´s a cheap knife from ebay, but it looks straigth. The shinogi-line is a little bit to low at the spot. Maybe i can fix it with the #120 sandpaper method.

 

[Barclid]

It´s a cheap knife from ebay, but it looks straigth. The shinogi-line is a little bit to low at the spot. Maybe i can fix it with the #120 sandpaper method.

Zero contact with the stone from shinogi to edge is very significant. That's a lot of metal to remove to fix. Unless you value your time very little I would recommend not going that route.

 

[da_mich*]

Zero contact with the stone from shinogi to edge is very significant. That's a lot of metal to remove to fix. Unless you value your time very little I would recommend not going that route.

I do the sandpaper to a Hilti WFO 280 Sander. Maybe it works.

 

[Barclid]

I do the sandpaper to a Hilti WFO 280 Sander. Maybe it works.

You do you.

 

[nutmeg]

You should go perpendicular to the shinogi at that grit

 

[nutmeg]

I do the sandpaper to a Hilti WFO 280 Sander. Maybe it works.

don‘t!
you need something stable.
Get a cheap 140 diamond plate and use very high pressure.
Machines won‘t work

 

[slickmamba]

I also say thats not worth the time.... How much was it?

 

[nutmeg]

I also say thats not worth the time.... How much was it?

Yes!
I checked the picture on a larger screen..
You can get a correct geometry without wasting too much steel only if you're an experienced sharpener.
This is also going to take ages..!

(So, don't get the diamond plate and change the knife IMO)

 

[da_mich*]

The knife costs 25$ or so. I try to fix it on weekend.

 

[nutmeg]

Very personal but I would pick the good knife at first instead of getting the bad one, working on it hours, ruining my stones, getting new stones.. and finally getting the good knife.

 

[slickmamba]

The knife costs 25$ or so. I try to fix it on weekend.

It'll cost you way more in time and stones than its worth, but if you enjoy the process and endgoal, go for it!

 

[plluke]

So I’m doing something similar. A $10 180mm yanagiba off eBay, supposedly white 2. Got it to practice single bevel sharpening. And to learn by trial and error.

Expected low spots and got them. 45 minutes of high pressure on an Atoma 140 and then Shapton 500 then 1k/6k and still not there. It takes a bit to figure out where the pressure should go and guessing which areas need to be shaved down to match lower areas.

I’m learning a lot and that’s the point but boy oh boy were you all right about it not being worth it. So much metal removed and it still just kind bad instead of terrible. And here I thought my crap knife would look like a nutmeg honyaki after an hour.

 

[da_mich*]

After 2h sharpening with King #240 its ready to use again.

 

[plluke]

Nicely done! Looks like I have another hour ahead of me.

 

[Benuser]

So I’m doing something similar. A $10 180mm yanagiba off eBay, supposedly white 2. Got it to practice single bevel sharpening. And to learn by trial and error.

Expected low spots and got them. 45 minutes of high pressure on an Atoma 140 and then Shapton 500 then 1k/6k and still not there. It takes a bit to figure out where the pressure should go and guessing which areas need to be shaved down to match lower areas.

I’m learning a lot and that’s the point but boy oh boy were you all right about it not being worth it. So much metal removed and it still just kind bad instead of terrible. And here I thought my crap knife would look like a nutmeg honyaki after an hour.

Wondering how you can go from the Atoma 140 straight to Shapton 500. Would expect a 220 in between.

 

[plluke]

Yeah not ideal but I don’t have a 220 yet. The atoma was for lapping, pulled in to experiment since the 500 wasn’t fast enough. Learning!

 

[inferno]

After 2h sharpening with King #240 its ready to use again.

yay

i got this stone for fast work. i found it on lidl. fastest stone i have.

 

[inferno]

So I’m doing something similar. A $10 180mm yanagiba off eBay, supposedly white 2. Got it to practice single bevel sharpening. And to learn by trial and error.

Expected low spots and got them. 45 minutes of high pressure on an Atoma 140 and then Shapton 500 then 1k/6k and still not there. It takes a bit to figure out where the pressure should go and guessing which areas need to be shaved down to match lower areas.

I’m learning a lot and that’s the point but boy oh boy were you all right about it not being worth it. So much metal removed and it still just kind bad instead of terrible. And here I thought my crap knife would look like a nutmeg honyaki after an hour.

dont use high pressure on atomas (if you can avoid it) or any other diamond plate either for that matter. you will wear it out very fast. but yeah it works faster if you push harder
its better to get a shapton 120/220 or so and go nuts. you can push as hard as you want. it will just cut faster.

 

[plluke]

Yeah I’m starting to learn that about diamond plates, thanks for the advice! I think I will get a 220 to play with.

Here’s where I got to between sandpaper, atoma, and currently Shapton 500 (ran out of time to take it up to 1/6k. Also the 500 scratch still doesn’t look uniform).

 

[plluke]

So much to learn, but at least most of the really terrible low spots are gone.

 

[da_mich*]

yay

i got this stone for fast work. i found it on lidl. fastest stone i have.

I think this is not a realy good stone, it will damage the metal structure with overheating. I will not recomment this electric sharpener for sharpening knives.

 

[inferno]

you have to cool the blade in water obviously. but it actually has a speed regulator. so its not really a problem imo. i have made knives with only this machine. hardened steel that i did not want to ruin the temper on.
and before you lose the temper you will burn your fingers... trust me. its a very good indicator its time to cool the blade.

and also: its not for sharpening...

 

[plluke]

@inferno a tangent but in case you haven't seen it: https://knifesteelnerds.com/2019/04/08/does-sharpening-with-a-grinder-ruin-your-edge/

For sharpening specifically there seems to be a measurable difference (I understand you're not using it for sharpening), which makes sense in retrospect but not what I would have guessed.

 

[inferno]

for sharpening with ANY machine you need to keep things COOL by dunking very often.

i only use mine for serious material removal. i've been using it lately to actually grind the main bevels of 2 62-63hrc monosteel blades.

but it would work very well for single bevel japanes blades too. and probably 100 times faster too since they are clad in soft unhardenable steel. which my blades are not.

this machine is about 100 times faster with a p80 grit belt for serious work than any kind of stone, you would not believe... but its not for sharpening. but can fix holes in bevels and do serious fast flattenings and so on.
but its not gonna be really truly flat, but then when the heavy lifting is done you can do the finishing work. the last 2-3% with stones. you still gonna need a coarse stone for this imo. like a 220.

its a cheap ass machine for 30 buck. and it works. the belts are like 1 buck a pop and last for about 10 minutes or so. but for what it do its very good imo. an actual really good machine of this type cost 3-400 or so. and its still not gonna give you a truly flat result. just so you know. for this use there is no difference between a good and bad machine. i have 2 or 3 years warranty on it too.

here are the knives i have ground on it.
https://www.kitchenknifeforums.com/threads/low-tech-ht-friendly-steels.42805/page-3

the single bevel santokus. on page 3 and 1. the sword i made with an angle grinder and the scandis i made at work on our shop grinder (it overheats things in like 1,5 seconds, can only do really coarse work on it and dunk every pass and since its so powerful you have no precision, unlike the lidl grinder).

its fun making sh1t!!

 

[plluke]

Very cool. Thanks for the info, great to see examples!