Although I prefer to free hand sharpen there are times when it doesn't work too well. Case in point, Chuckabochos (Japanese vegetable cleavers). It is very difficult to maintain a constant angle due to the width of the blade, in this situation, 110mm wide by 220mm long. This knife is a San Mai construction Moritaka with the cutting edge made of Hitachi Blue Super Steel and the cladding is a soft carbon steel that turns to red rust if you so much as breath on it. Consequently I have to wash, dry, and coat with mineral oil after every use.
To sharpen it I use an EdgePro Apex, little brother to Chico's Pro model and baby brother to Joe's Gizmo. In this picture you can see that the blade guide has been removed (upper right) and the blade table has been covered with painters' tape to minimize scratching. The stones are soaking in the sink at the left.
Without the blade guide the knife must be held in place with only the blade table for support.
I gave the knife a ten degree secondary bevel (relief bevel, back bevel) stopping just short of burr formation, then polished that part. Then I cut a fifteen degree primary bevel (cutting edge, micro bevel) and formed a burr.
The burr was removed by stropping the edge on a piece of 1/4" brass channel. Some of you may not have heard of this. On certain steels magic occurs. Two light swipes a side and goodbye burr.
Following burr removal I went through the stones with final polish on the 800. After that I stropped with both .5 micron chromium oxide and .25 micron diamond spray charged leather. No, that's not rust on the edge - something about the flash and my inability to take a decent picture....
The reason I went to the fifteen degree edge is because I use the Chucabocho for chopping vegetables more than slicing them. I needed a robust edge. Here's a picture with the Chucka snuggling up to my other chopper, a 240mm Aritsugu "A" model Gyuto sharpened on the left side only.
To sharpen it I use an EdgePro Apex, little brother to Chico's Pro model and baby brother to Joe's Gizmo. In this picture you can see that the blade guide has been removed (upper right) and the blade table has been covered with painters' tape to minimize scratching. The stones are soaking in the sink at the left.
Without the blade guide the knife must be held in place with only the blade table for support.
I gave the knife a ten degree secondary bevel (relief bevel, back bevel) stopping just short of burr formation, then polished that part. Then I cut a fifteen degree primary bevel (cutting edge, micro bevel) and formed a burr.
The burr was removed by stropping the edge on a piece of 1/4" brass channel. Some of you may not have heard of this. On certain steels magic occurs. Two light swipes a side and goodbye burr.
Following burr removal I went through the stones with final polish on the 800. After that I stropped with both .5 micron chromium oxide and .25 micron diamond spray charged leather. No, that's not rust on the edge - something about the flash and my inability to take a decent picture....
The reason I went to the fifteen degree edge is because I use the Chucabocho for chopping vegetables more than slicing them. I needed a robust edge. Here's a picture with the Chucka snuggling up to my other chopper, a 240mm Aritsugu "A" model Gyuto sharpened on the left side only.
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