Sharpening single-bevel knives with guided systems

Shmackey

Shmackey

Joined
May 5, 2000
Messages
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I'm familiar with how to sharpen an usuba or deba on regular stones freehand. Wondering if anyone has advice on sharpening them on a guided/clamped system. I'm concerned that the extreme angle precision will produce a very different result when working the main large bevel and then the steeper apex bevel.

The freehand result is usually almost a large convex bevel, not a giant polygon-looking thing.

Also wondering about the best approach to the left/flat side with such a system.
 
When I free hand sharpen a single bevel knife, I use a 15 degree angle on the bevel side. As I transition through finer and finer stones, I watch for burr formation. If I notice a burr, I wipe it, edge trailing, back into the grinding plane using the side of the ceramic blade on a large kitchen knife. When I finish on the finest stone, I lightly steel the knife on the ceramic knife, edge leading, being careful to change the angle on each side to compensate for the difference in planes. IE I hold the knife a little higher on the ground side and a little lower on the non bevel side.
 
I would not recommend and please don't. Single bevel knives NEED to be hand sharpened, sharpening these blades is more like a dance, more to it than just "sharpen to this angle".

If you are getting a lot of convex in your single bevels that is just you getting impatient. It can take a lot of time to grind down the hard steel and usually frustration kicks in and you start raising the sharpening angle until the edge reaches an apex. I know I have to watch myself because it can happen subconsciously and before you know it you have already started making a convex plane.

It's best to view the blade road as two different bevels. When you lay the bevel on the stone and you keep pressure closer to the middle or spine of the blade then you will be removing metal from the upper soft iron. When you move finger pressure to the edge and slightly raise the spine about 1mm you will sharpen the hard steel. So, you really want to have two angles on the blade road because sharpening it all at once it incorrect. Finally, you want to microbevel these blades, without microbevels these traditional knives will fail simple tasks.

As for sharpening the backside again, it needs to be done on a stone, there are specific ways you push on the blade that must be followed or you can damage the Ura.
 
Jason B. said:
I would not recommend and please don't. Single bevel knives NEED to be hand sharpened, sharpening these blades is more like a dance, more to it than just "sharpen to this angle".

If you are getting a lot of convex in your single bevels that is just you getting impatient. It can take a lot of time to grind down the hard steel and usually frustration kicks in and you start raising the sharpening angle until the edge reaches an apex. I know I have to watch myself because it can happen subconsciously and before you know it you have already started making a convex plane.

It's best to view the blade road as two different bevels. When you lay the bevel on the stone and you keep pressure closer to the middle or spine of the blade then you will be removing metal from the upper soft iron. When you move finger pressure to the edge and slightly raise the spine about 1mm you will sharpen the hard steel. So, you really want to have two angles on the blade road because sharpening it all at once it incorrect. Finally, you want to microbevel these blades, without microbevels these traditional knives will fail simple tasks.

As for sharpening the backside again, it needs to be done on a stone, there are specific ways you push on the blade that must be followed or you can damage the Ura.
Click to expand...

Cool. Works for me. What grits do you like to use on an usuba that already has the right profiles but needs sharpening?
 
I typically use a 1k to start most any single bevel if it has not been damaged. I also just work the ura, which is more important than most will admit, and the hard steel on the front bevel. Once those are to my liking i usually blend the blade road with a muddy 1k then microbevel and polish the ura with a 6k. If its a really good blade ill use the 16k Shapton glass for the micro.
 
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