Wednesday, 7 October 2015

Edge Joining, using a Nagura set and getting the most out of your Japanese natural stone

Here is a article on maxing out a Jnat to get the keenest edge possible. It's not something that needs to be done on every razor and I would generally recommend this way of finishing to more experienced Jnat users that are trying to get the most out of their stone. This applies to most natural stones.

In this progression I've decided to use a full set of mikawa naguras on my Wakasa asagi which I don't do often, this may be a bit of an overkill for me but it never hurts to make sure you've done enough prefinish work to prepare your blade for a final polish, you do not need to go through an entire nagura set, infact you can go straight to your base slurry on your stone, start with a heavy slurry and progressively thin it out, for the purpose of this article, I will use the whole set. In this case the razor I've chosen to use is a Japanese made Parker due to the fact that it was the dull razor that I had lying around.

I've started by setting the bevel on my Atoma #1200 diamond plate, a new primary edge has been established. The scratches are deep and the edge is very harsh and toothy as expected but this is only the beginning.

Here I have drawn the edge across the stone, this is called edge joining. It eliminates the toothiness but it comes with a price. Your edge becomes completely dull.

The next task would be to reset the bevel on a whetstone of a similar grit. The purpose of this is to convert the harsh diamond scratch pattern into less aggressive scratches, in this case it was my chosera 1k which will also re-establish the bevel using a minimal number of strokes. In the next photo the edge is no longer dull. 

Now it's time to move on to the Wakasa and Mikawa naguras. I raise a slurry using a Botan. I do a series of 20 circles for speed cutting and to also allow the slurry to break down and become finer followed by 20-30 x-strokes. The 1k scratches are very faint and mostly remain behind the edge, by that stage it's time to move to the next progression or you can keep going until the scratches are completely gone, that is up to you.

I move on to the Tenjyo, mejiro and Koma and do about 30-40 x-strokes through each progression. By the time I was done on the Koma, the edge has taken a better polish, it's ok to strop and shave from here but I would recommend raising a slurry from your base stone with a tomo nagura or a well worn diamond plate as the final polishing stage for extra keenness.

In this case I have used a tomo nagura on my Wakasa and did the same thing, worked the slurry until it became finer and thinned it down with water. By then it the edge was highly refined and more than ready for a shave but this time, I have decided to squeeze as much keenness as possible out of my stone, I went to plain water and performed about 10 x-strokes, by then I felt suction under the blade, this is a good time to stop. I stropped the razor on clean leather doing 10 passes. This slightly rounds or creates a slight convex at the very edge, this eliminates the suction on the stone for the next few strokes. I went back to the stone and did another 8 strokes under running water, that was all it took to bring back the suction, this ensures you have the same results throughout the entire edge. This is my preferred way of getting the most out of my stones and here are a couple of photos of the finished edge which has taken a very high polish. 

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