12-10-2017, 09:00 PM
Finally got the chance to do some sharpening. I sharpened up both Japanese kitchen knives and had no trouble getting to the usual level of sharpness for those. I used a 220 Norton waterstone, then a King 1000, each at 12 degrees per side (dps), followed by the Sharpmaker brown rod flats at 15 dps. The resulting edge would tree top my arm hair with the grain and against, and sever a hair held between my fingers, similar to a hanging hair test, but instead of about an inch from my fingers it's more like 1/8". I used the larger knife, a 175 mm Misuzu Bunka, to cut some apples and onions, and the edge dulled from corrosion. I resharpened it tonight starting with the 1k King waterstone, followed by a 4000 grit King water stone. Sharpness was about the same at severing a hair about 1/8" from point of hold. I'm still getting the hang of the 4k stone.
Before resharpening the Bunka, I cut into the 1k stone to remove any corroded material. The double burr is not unique to the ceramic rod, as cutting into the 1k stone produces the same effect.
I have the 2 stainless knives left to sharpen, but one requires rebeveling to my standard 12/15 dps/microbevel for kitchen knives. It will be a couple more days before it's done.
Also, I had a chance to check out the size effect article. I have heard of this before, but it was related to silicon carbide whisker reinforced composites. As size gets smaller, in these at least, fewer flaws are present in the structure, and they approach the theoretical strength, which is over 1,000,000 psi. I will have to read the other link later. I do not work with such large structures or thick steel sections and had not heard of the size effect in the negative direction. Well, I had, but I thought it was something specific to rolling heavy sections of plate and related to differences in cooling rates and alloy distribution and such. I hadn't heard of it being applied to structures as a whole, nor to reinforced concrete.
Before resharpening the Bunka, I cut into the 1k stone to remove any corroded material. The double burr is not unique to the ceramic rod, as cutting into the 1k stone produces the same effect.
I have the 2 stainless knives left to sharpen, but one requires rebeveling to my standard 12/15 dps/microbevel for kitchen knives. It will be a couple more days before it's done.
Also, I had a chance to check out the size effect article. I have heard of this before, but it was related to silicon carbide whisker reinforced composites. As size gets smaller, in these at least, fewer flaws are present in the structure, and they approach the theoretical strength, which is over 1,000,000 psi. I will have to read the other link later. I do not work with such large structures or thick steel sections and had not heard of the size effect in the negative direction. Well, I had, but I thought it was something specific to rolling heavy sections of plate and related to differences in cooling rates and alloy distribution and such. I hadn't heard of it being applied to structures as a whole, nor to reinforced concrete.