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Post by TheMu on Jul 31, 2014 8:46:02 GMT
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Post by Jakeonthekob on Jul 31, 2014 20:34:36 GMT
This setup will work very well but you have to be careful about forming another ridge because your sharpening plank is in line with the edge but not across the middle of the niku. Also, a katana is curved while your sharpening plank is straight so you won't get truly even edge angle and sharpening if that matters a whole lot to you. I guess you can just move the supporting plank around depending on which area you want to sharpen.
Good stuff.
-Jake
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Greg
Senior Forumite
Posts: 1,800
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Post by Greg on Jul 31, 2014 21:22:50 GMT
This has made me realize that it's much simpler to make a jig to bevel knives with. Well done
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Post by TheMu on Aug 1, 2014 14:26:45 GMT
Thanks jakeonthecob, Good points there. This sharpening rack is still in development phase so all ideas are most welcome! Sharpening rack isn't adjusted properly in the pictures (though it's pretty close to what I'm aiming for). Pictures are just to explain the basic idea. I'm sharpening only the mono-uchi at first, so I think the straight wood plank is sufficient for now. When I'm going to sharpen the whole blade and finish it, I will carve the supporting wood plank to match the shape of the blade. This is how I'm about to grind the blade: I might smooth down the ridge but I also might leave it there. Depends on how it looks and works when finished. Here's a picture of test cutting and the rough sharpening: Geometry feels really good when cutting. A while back I ground the niku down quite a lot, and now I took the niku off completely. That made a big difference considering cutting capabilities of the sword. I test cutted an oak shaft and edge didn't roll or get nicked. However it might not withstand a bad cut, I suppose. Thanks Greg, Good to be of use
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Post by chrisperoni on Aug 1, 2014 16:01:48 GMT
Great stuff! You probably already thought of this - When you make a curved support bar at the back of the jig, I would add a pin to the underside of the cross bar (the one the sanding block is attached to), so the cross bar follows the curved bar exactly. Maybe even cut a cgroove into the support bar or add a bearing to the pin for smooth movement.
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Post by Jakeonthekob on Aug 1, 2014 16:44:04 GMT
kool man. My only concern would be possible wedging from decreasing the surface area of the primary edge because from your illustration, that would mean that you are essentially creating a 4 sided cutting plane. However if the edge is sharp, then I think you should have no problems.
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Post by aussie-rabbit on Aug 7, 2014 4:53:23 GMT
I have used a similar method for about 35 years, today I sharpen "freehand" without the block but have a look here about half way down for polishing your edge. viewtopic.php?f=19&t=13285
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Post by TheMu on Aug 8, 2014 18:47:52 GMT
Thanks everyone.
Here's a few pictures of the finished edge:
I'll finish the rest of the blade later. Thanks aussie-rabbit for the link, I'll look into it.
Geometry isn't perfect so some improvements are needed. What chrisperoni suggested might work pretty well. As it is now, the sharpening rack does the job for beaters like this particular sword, but without any improvements I wouldn't use it for quality swords.
And jakeonthekob, you make a valid point. Blade seems to cut like a light saber, but I'll run a few more cutting tests and decide then what I'm going to do with the blade geometry.
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