# Rounding the spine...



## Zwiefel (Oct 7, 2012)

I recently purchased a Zakuri from the BST here and got a chance to look it over last night. This afternoon I decided to see if I could round the spine a bit, it's a bit sharp as I received it.

The only tool I had handy to do the work was 400 grit wet/dry sandpaper....but I didn't have a vise to hold the knife steady....but I guess the sandpaper could be held steady just as well:







I inverted the petty and moved the spine back-n-forth while adjusting the angle from about 40* to about 90* and repeated for the other side of the spine. It was surprisingly similar to the motion for sharpening...need to mind the edge a bit more though :idea2: Certainly not the most sophisticated rounding I've seen...but it made a pretty big difference in the ergonomics. Was pretty pleased with my results considering this is the first time I've tried to use sandpaper for anything with a knife. 

Also decided to try to get rid of some scratches from sloppy work thinning behind the edge on a gengetsu. Still more work to be done, but I need a higher grit sandpaper to finish it, i think. Before and after:








Certainly not the most sophisticated repair work I've seen on here...but I'm pleased with it for a first attempt. Need to find some 2k grid sandpaper now...and something better than a couple of chopsticks for a backer!

Sharpened the Zakuri and Gengetsu as well. Was able to raise a burr on both sides, with the 1k and 5k in no time. Both are cutting well. Aside from food, I also like to cut paper all along the edge to get a sense of the performance throughout. I have a lot of trouble doing that with the heel as I've not been able to cut with a push motion, only a pull motion. Today I had the idea to hold the knife by the spine with the handle away from me, like this:





That allowed me to make a pull-cut from the middle of the edge all the way to the heel. Has anyone else tried this technique?


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## bluntcut (Oct 7, 2012)

Which type of sandpaper is that? I use SiC wet&dry sandpapers (120 - 2000 grit) for rounding, polishing and sometime sharpening.


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## Zwiefel (Oct 7, 2012)

bluntcut said:


> Which type of sandpaper is that? I use SiC wet&dry sandpapers (120 - 2000 grit) for rounding, polishing and sometime sharpening.



I can't find the exact product online...but it was "3M Auto Wetordry" 400, 800, and 1000 grit, I think it's in 9X9 sheets, pack of 5 (for each grit). About $8 for each pack. I don't know anything about selecting sandpaper, I just picked something labeled "wet/dry" that had a good range of grits.


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## bluntcut (Oct 7, 2012)

Well, mine SiC w&d are quite black in color. I asked because from your pic, the sandpaper looks dark-orange-ish as if it was a garnet sandpaper.

Edit: Garnet has low Mohs (hardness), which mostly use for soft material wood/paint/etc...


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## Zwiefel (Oct 7, 2012)

bluntcut said:


> Well, mine SiC w&d are quite black in color. I asked because from your pic, the sandpaper looks dark-orange-ish as if it was a garnet sandpaper.



gotcha...I think it's just the lighting...there is a very warm incandescent lamp directly above that part of the counter. I'm red-green color-blind, but it seems like a pretty dark charcoal color to me in person. The photo does look a bit orangy though.


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## Eamon Burke (Oct 8, 2012)

Glad you got your hands dirty! 

That sandpaper pic fooled me too, but I see it now.


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## Cutty Sharp (Oct 8, 2012)

Thanks for posting. I'm hardly on the 'Pro Craftsman' level, so am happy to read. Recently received a 3M wet/dry set to play with polishing, but am only somewhat pleased with the results. There must me more to learn, I guess...


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## Zwiefel (Oct 8, 2012)

Cutty Sharp said:


> Thanks for posting. I'm hardly on the 'Pro Craftsman' level, so am happy to read. Recently received a 3M wet/dry set to play with polishing, but am only somewhat pleased with the results. There must me more to learn, I guess...



I get fairly intimidated with the average quality of the craftwork on here, wanted to share a noob experience 

I'm pleased with my result...but not satisfied. Def could be done better...but that's for next time...at least I don't feel like it's an eyesore anymore. Honestly, i was really embarrassed to show anyone the before state...but Eamon was kind and encouraging 

OTOH, if anyone wants to compare .BAT scripts, that's something I have 20 years of experience with!


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## Dave Martell (Oct 8, 2012)

Hey we all start somewhere and I'm happy to see your input here. :thumbsup:


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## brainsausage (Oct 8, 2012)

This is inspiring for sure Zweifel. I've been playing around with learning some of these very same things, as well as getting into doing my own re-handling. Nice work


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## Taz575 (Oct 9, 2012)

For a backer for sanding, there are a few things to use. WoodCraft and other wood working places sell a hard felt block or a cork block, which work well for backers. Or you can get those rubber sanding things that have a flat bottom and are curved on the top with the little spikes in a slit in the rubber on each side that hold sand paper inside the slits. I buy them and then cut them in thirds so I have the solid flat piece from the middle. Very firm and works well as a backer for sanding. I keep one long end square and I round the other long end.


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## Zwiefel (Oct 9, 2012)

I've got one of those rubber thingies....somewhere. Haven't seen it in about 15 years though! Why remove the part that you attach it with though?


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## Taz575 (Oct 9, 2012)

It can be used as is, but for me, it's easier to cut it into a smaller section, and it gives more pressure over a smaller area. Works nicely when shaping handles or polishing bolsters and lets me get into tighter areas. For rounding the spine, using it as is should work, but with the blade polishing and handle work, I like it smaller.


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## Zwiefel (Oct 9, 2012)

That makes sense, thanks Taz!


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## Cutty Sharp (Oct 9, 2012)

My 3M wet/dry came with a kind of firm rubber sponge block to act as a 'backer'. Seems fine for the purpose. Of course you can use the ends or side or face depending on the pressure you want to exert.


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