Thread: Japanese Nagura stone

what about the smooth surface, steel plasticity can-o-worm you opened over in another thread?

kevint,
Steel plasticity can of worms? Can you cite that thread for me? I'd like to (re?) read that one. However plastic steel may be, I'm not sure I see the connection of that to the surface fineness or surface "feel" of a hone. Unless you're worried about the plasticity of steel being sufficient to allow it to flow into the ruts left by lapping the hone on a device with a coarser grit rating than the hone itself.

OK, some time ago when Robert Williams had his website there was a post commented on by Robert, Mike Blue and MParker. Part of the thread discussed the plasticity of steel and honing. This was a surprise to me since I had never heard of steel having plasticity.

At what level this comes into effect I do not know and I have not brought it up here simply because it would be so technical that I doubt we can make use of it.

OK , that's the can of worms.

AHA! Thank you Randy.

Now those of us with screwdrivers can begin to pry off the lid and delve into the mysteries of...



plastic??

http://straightrazorpalace.com/advan...mentary-3.html

right there near r the end than start.

Besides the issue of better tactile feedback ("feel") being provided by a smoothed out polishing stone is the fact that a stone will cut more efficiently in this state. A smooth stone presents more of it's surface (area) to the tool being sharpened thus cuts faster and often provides better results in edge quality than what can be achieved by using the same stone in a rougher state.

FWIW - I use a DMT Dia-Sharp D8XX for all my stone flattening/lapping. For polishing stones I follow that with a D8C and then I further smooth with a synthetic nagura, my favorite being a Naniwa 600x (supplied with Choseras).

I find that the most enjoyable surface on my
Nakayama can be had by lapping with a D8C
followed by the use of a Nakayama rubbing
stone. I continue to use the rubbing stone,
which is basically the same as the hone itself,
to refresh the surface between honings.

- Scott

within reason the texture of a bonded abrasive doesn't matter. It will wear down/smooth out with use. This is what I argued with my sedimentary (and as I was corrected, metamorphosed sedimentary) rock. The grit is determined by the cutting particle size, not the texture of the bonding agent.
If you use something solid and hard than steel (jade, quartz, jasper) the texture would matter as the surface itself is doing the cutting.
That being said, in theory you can lap with a 120 grit paper and be just fine. It just leaves scratches. I lap at 120 or 200ish, then quickly (fivish mins of work) work my way up to 1000 grit paper. Just to get rid of cosmetic scratches on my naturals and Swaty's.
my .02

has anyone noticed differences between using natural nagura vs. synthetic?

especially those very soft white ones.

personally i find it very difficult to tell the difference between 400 and 1000 as regards the feel of steel on stone. maybe the difference is constant wash vs slurry acting with the plate. Or sandpaper(hate it) vs plate, or coarse stone vs paper or plate.

jade, quartz jasper must all work the same as any other hone. ultimate smoothness - such as sub-micrometer mirror polish may lead to more of a burnishing effect rather than honing- just making stuff up but its a fact now

Originally Posted by kevint

jade, quartz jasper must all work the same as any other hone. ultimate smoothness - such as sub-micrometer mirror polish may lead to more of a burnishing effect rather than honing- just making stuff up but its a fact now

They don't. And won't. A coticule cuts with garnets that are within a certain size range, giving it it's grit. Naniwas, Shaptons, Nortons, all have little pieces of grit that do the work, most of the stone is adhesive to hold that grit in stone form, like grit on a sand paper. The glue breaks down releasing more abrasive to cut.

The solid crystalline rocks that are harder than steel will do whatever finish they are given. For example, steel files. Lets say you made a file out of quartz. If you make the grooves large, it will remove lots of metal= coarse grit. if you make small grooves, it will remove less metal =finer grit. If you polish it, it will smooth/polish metal = finishing grit.

Please correct me if I'm wrong...

Because last time I checked if you lap a Norton 1k up to 325 its 1k, if you lap it up to 1k its still 1k, and if you lapped it with 2000 its still only 1k. If you lap a Norton 8k up to 325 its still an 8k, if you lap it up to 1k its still an 8k, and if you lap it up to 2000, its still an 8k. Because waterstones almost always are bonded abrasive, and the size and percentage of abbrasive determines grit, not smoothness. With something homogenous, single-crystaline and harder than steel, ie a textured surface, ie a jade jasper quartz etc hone, the finish on the surface determines the grit, like a series of steel files getting finer and finer.