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 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?