very deep scratches near edge / hand sanding

timos-

timos-

Knifemaker / Craftsman / Service Provider
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Oct 22, 2012
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I have a 210mm gyuto in 154cm Ive been working on and off for maybe 2 years now. Ive passed it around a bit and used it myself, finally I decide to refinish it and take it down to more laser-like cutting geometry. Its lean and mean, but Ime having a hell of a time getting nice uniform finish on the blade. I was hand sanding with some cheap 3m 120 grit paper to get the last of the 80 grit marks out. Now I move on to 220 grit and somehow there are waaay deep scratches fromt he hand sanding. I mean like deeper than 80 grit. The edge is so thin I am really hesitant to hand sand it with 80 grit. What happened here? Is this just something that happens with cheaper quality paper or was it error on my part? When you get deep scratches near the edge of a blade that is really thin do you keep it yourself, try to sand em out or what? Im pretty dissapointed, Ive got about 20+ hours in shaping this blade.
 
i always finish the bevel of my kitchen knives with whetstones, but if you support adequately your edge from below you could hand sand it pretty heavily
 
I should note that the bevel is slightly hollow ..kinda about 60-70" radius ..i love how it cuts but maybe i need to make up a custom curved sanding block for this one
 
Cheap sandpaper will have stray bits of different size grits in it and should be used for sanding dry-wall.
 
Stezann, I wish I could use a stone. I think with this knife ive made things crazy difficult on myself...not only is the bevels hollow but the tang is tapered and the spine is too...Im gonna have to get creative with some shims or something...
Nathan, i dont know what i was thinking using that home depot paper, sheesh, maybe i can do a 120 grit hand sand really nicely following the edge (no fish hooks)..ive seen it done well by a few makers, maybe it was 220 though.
 
You have to get scratches out at a different angle than the scratch or your abrasive falls into the scratch and carries it deeper. This is a good application for die makers stones.
 
If you use WD-40 it will help tremendously with the fish hooks. Go back to 150 or so and clean those deep ones up. I finish at 400 using WD-40 and am amazed at how much cleaner my results are
 
What did you use to make the slight hollow? Modified platen or by hand? Might go back to how it was first ground and re start your belt progression. Or if by hand make a custom sanding block (like you were mentioning) to fit the hollow and use Redline Rynowet paper.
 
Lee valley has pretty good sandpaper, and the 3m or Norton in the auto department is pretty good.
 
I used one of Nathans 36" radius platen for initial bevel, then lean a bit back on the bevel to widen it, then lean a bit forward in the bevel to get close to my desired edge thickness before sharpening. I think originally I was trying to mimic some grinds ive seen of Jerry Hossum, where the gentle hollow grind sort of extends into something more flat. Sooo I have a long way to go figuring out how to finish this geometry in a time efficient manner. thanks all for the tips and encouragement , im maybe gonna try and get this one right, even if it take me another 6 hours :/
 
Rhinowet Redline sandpaper ALL THE WAY :thumbup: ... I can't believe nobody has mentioned/recommended it to you yet! :confused: I suggest gettin a pack of each of these grits: 80, 120, 220, 400, 600, 800, and 1000. If you want to go all the way up to 2500, go for it. But at least get the grits I mentioned, they work great in succession without having to get any of the other grits inbetween them. Here is were you can order them in 10 or 50 sheet packs per grit. http://www.supergrit.com/products/RedlineRedFlexSheets

I sand with amonia free windex because it works great as a lubricant and is way less messy than oil. I get amonia free because it just can't be good breathing in those amonia fumes that often, especially when hand sanding for a while on every blade you do.

~Paul
My YT Channel Lsubslimed
... (It's been quite a while since I've posted any new vids)
 
I use Rhinowet Red as well as Norton Black Ice and 3M wet/dry auto finishing paper and all work well wet The 3M is great but doesn't last long, the Norton is more aggressive and the Rhinowet is in between. Try them all. Larry
 
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