A Sad Japanese Kitchen Knife

B

Bugout Bill

Joined
Jan 2, 2013
Messages
1,508
For as long as I can remember, my parents have had this Japanese carbon steel kitchen knife. Unfortunately, they have not treated it too kindly. My parents were about to throw it out tonight, but I decided to try and save this blade.

img0649y.JPG
[/IMG]

I have no idea what manufacturer this is, but here is the makers mark.

[video]
img0652bd.JPG
[/video]

img0651qk.jpg


The chisel ground blade has some pretty severe chips, as well as a non-existant tip.

I have recently begun freehand sharpening, but I have a fair ammount of experience with the Sharpmaker. As for actual equipment, I have a sharpmaker, ultrafine sharpmaker rods, and a 6 in DMT diasharp extra-course. Could I save this knife, or is it a lost cause?

Any imput will be appreciated, thanks.
 
Anything can be repaired and that old knife would be a blast to fix up. If you decide to discard it, let me know and I'll send you the money and new address for it...Herb
 
It will be alot of work but worth your effort + experience gain. Show us a picture looking straight down at the whole blade lays flat. making it easier for us to mockup a new profile along with an repair plan.
 
DO NOT USE A SHARPMAKER!!!!!

You do not have the proper stones to correctly sharpen that knife. It's much more than just a chisel grind and require a specific style of sharpening.
 
Your extra-coarse diamond stone could reprofile the edge and fix the tip, but it's a big gap from that stone to the fine stones of the Sharpmaker. You might try a ladder of sandpaper grits as a bridge to get you to where the Sharpmaker would work, but the Sharpmaker uses two sharpening angles. The reprofiling would have to match one of those angles. The 40 degree angle would be easiest, but the 30-degree angle would be best for a kitchen knife.

Try the extra-coarse stones and see how the metal responds. I'm guessing that this is a cheaper Japanese knife because of the grind, so it's not easy to know what kind of steel you're dealing with.

Oldgoat has the right attitude: "that old knife would be a blast to fix up."
 
knifenut1013 said:
DO NOT USE A SHARPMAKER!!!!!

You do not have the proper stones to correctly sharpen that knife. It's much more than just a chisel grind and require a specific style of sharpening.
Click to expand...


Given that edge and the amount of metal that has to be removed, he could put any kind of angle he wants on the knife. If he reprofiles it to 30 degrees, the Sharpmaker could handle it from there.
 
Twindog said:
Your extra-coarse diamond stone could reprofile the edge and fix the tip, but it's a big gap from that stone to the fine stones of the Sharpmaker. You might try a ladder of sandpaper grits as a bridge to get you to where the Sharpmaker would work, but the Sharpmaker uses two sharpening angles. The reprofiling would have to match one of those angles. The 40 degree angle would be easiest, but the 30-degree angle would be best for a kitchen knife.QUOTE]

The grit difference was one of my bigger worries. I might decide to snag a DMT fine stone; I've fallen in love with diamond stones, but extra-course is a bit much for regular sharpening.. I am well aware of the limitations of the sharpmaker, I was intending to get it as close to the original angle as possible with the diamond stone before then freehanding on the sharpmaker rods.

There might be some benefit to increasing the edge angle to 30 degrees, my mom said that the chipping happened during normal use, so increasing the edge angle might increase durability.
Click to expand...
 
Last edited:
Are you planning to match the factory bevel or add a new bevel?

If you would like to repair it to like new condition you need to lay the factory bevel flat down against the stone and start removing material on the entire bevel surface. It will likely be slow going even with your super coarse diamonds. I think the sandpaper method is the way to go since you will need to refine the scratch pattern significantly from your super coarse diamonds to get close to where the sharpmaker stones used as bench stones would be useful.

As a last resort there are some sharpening services that specialize in the maintenance and repair of Japanese kitchen knives.
 
ChapmanPreferred said:
Are you planning to match the factory bevel or add a new bevel?

If you would like to repair it to like new condition you need to lay the factory bevel flat down against the stone and start removing material on the entire bevel surface. It will likely be slow going even with your super coarse diamonds. I think the sandpaper method is the way to go since you will need to refine the scratch pattern significantly from your super coarse diamonds to get close to where the sharpmaker stones used as bench stones would be useful.

As a last resort there are some sharpening services that specialize in the maintenance and repair of Japanese kitchen knives.
Click to expand...

I think I am going to add a new bevel, the old edge seemed a little too thin for general kitchen work. Also, the only sandpaper I have available is 150 grit wet-dry. I have gone from sandpaper to medium spyderco rods with no problems before, but could I go from diamonds to sandpaper.
 
The knife type is a yanagi-ba, it is a traditional single bevel knife with a hollow ground backside. This knife is made for the specific task of cutting fish that has been de-boned. It's a sushi knife.

The method to sharpen this blade (kataba) is not like normal 50/50 ground knives, this knife is sharpened flat on the backside (uraoshi) and on the front side the main bevel all the way up to the sholder (shinogi line) is sharpened. It's also a complex sharpening because the large bevel face is made up of two types of metal the edge metal (hagane-hard metal) and the clad metal (Jigane-soft metal). USE ONLY WATERSTONES.

If you sharpen normally you have a great chance of causing permanence damage and in the process will make the knife useless.
 
It appears to be laminated. The edge steel will be hard & brittle, which would explain why there is so much chipping. Such knives are specialist slicers, & don't take well to chopping, or being forced through a bone.
Since it is a chisel grind, the edge steel probably forms one side, the "unground" side. If you look closely, you may find that this side is slightly concave.

I think this knife is worth doing up, & when reground & sharpened will be an excellent knife.
If your inspection agrees with what I have described, don't try to change the grind. Put in the time with a coarse or extra coarse stone & grind that big flat bevel untill the chips are gone. Somebody who knows what they are doing with a slow moving beltt grinder could help a lot, but a newbie could wreck it.
The only use for a sharpmaker would be to remove the burr from the back edge when finished. Sharpmakers were not intended for these knives. The Japanese use stones.
You can use the sharpmaker as a stone: fit two rods beside each other in the bottom of the plastic holder. That would be a fine, finishing stone. You have a long way to go before then.
I would love to have saved this knife from the dump.
 
Thank you for all the imput. I have taken a closer look at the knife and have compared it to a reference on wikipedia, and it appears that Knifenut1013 is correct. The fact that it is a sashimi knife would probably explain why it performed so poorly as a general kitchen knife. :o

I don't really know what I am going to do with the knife, but I do know that I am going to keep it. I think I lack the equipment, skill, and perhaps patience to fully restore this blade. I may look into having it professionally done, but in the mean time I think I am going to clean the rest of the rust off and oil it up.
 
Knifenut is totally correct.
My advice was based on the assumption that you are not a sushi chef, & wanted to to use & maintain this knife in your own kitchen.
If you want a collectable, or learn to make sushi, or learn to restore sushi knives, follow knifenuts advice.
Either way, it will be fun & you will learn a lot.
 
Your biggest issue is the bend, they sell the tools to bend it back but they are expensive. Luckily you can make them from some wood and a hand saw, look them up, they are pretty simple.

The hard part will be the actual bending, it will take some force and might even feel like a workout as you must do it progressively. The results will be one of two things, a straight blade or a broken blade. If you manage to get the bend out and remove all the rust with proper sanding then the sharpening might actually be viewed as easy :D

To sharpen you must first remove the damage. Start by grinding the edge 90 degrees to the stone until the chips are gone and the tip is reformed. Don't forget to grind the spine down equally at the tip to keep proper distance between hard and soft metals and also to have proper tip placement.

Once you remove the bend, rust, chips, and reform the tip you can begin to sharpen. Sharpen on the hard metal until the burr forms on the backside then grind the soft upper metal to "thin" the back bevel. Video #1 in the above link describes this grinding process. Remember to never deburr the backside with anything below 1000 grit.

I don't usually, but I would recommend a 220, 1000, and 4000 grit King brand waterstones. They are a lower grade stone compared to what's available but will work the best with that knife.
 
Last edited:
knifenut1013 said:
snip
Click to expand...

Hey, thanks for advice. I don't think I am going to try and sharpen it at the present time. I don't really have the necessary equipment or skills to properly sharpen this knife. I've gotten most of the surface rust off, so it should hold up as a nice display piece.
 
The only thing I have to add is to work at it in short sessions spread out over several days, so you don't get bored or frustrated.
 
The Japanese characters on the blade are the Maker's Mark. It reads: "Made by Seiko."
It's a man's name, rather than a company. It's possible that the person pronounces his name a bit differently.


Stitchawl
 
stitchawl said:
The Japanese characters on the blade are the Maker's Mark. It reads: "Made by Seiko."
It's a man's name, rather than a company. It's possible that the person pronounces his name a bit differently.

Stitchawl
Click to expand...

Do you think that this is a valuable custom knife by Mr Seiko? Or is he a production type operation?

Either way, this looks like a very interesting project and the op is likely to learn a bit about sharpening from it. But if it's a valuable knife, it might be better to send it to someone who can do the job properly.

Allen
 
You must log in or register to reply here.
Back
Top