Japanese 800 grit wheel is now available from a German seller

[wootz]

Hi guys,

The Japanese Sun Tiger 800 grit grinding wheel has become available as of today from this German seller:
http://www.fine-tools.com/Tormek.html

Note that Japanese grit JIS #800 corresponds to US ANSI #600, and European FEPA #1200, i.e. is somewhat finer than 'finely' graded Tormek #1000.
The main advantage of using a dedicated 800 grit stone over graded Tormek standard SG is that you do not have to grade finer grit from the original 220 grit, and hard grading can untrue the wheel and get the corners out of square (the latter mostly frustrates knife sharpeners).

In 2009 Ionut had said all I could possibly say on this topic, so I just refer to his original post, a fragment of which I quote below:
http://forum.tormek.com/index.php?topic=897.0;nowap

"... the so called 1000 grit in my opinion is far from it. If you compare the scratch patterns between the Tormek wheel graded at 1000 and an actual 1000 stone there is a huge difference, and if you add a magnifier glass everything gets amplified. I've tried hardly to grade the stone to get closer results to the real 1000 I pressed the grader so hard I stalled the motor and the best thing I've done when pressing so hard and for long time was to untrue my wheel.
Using a 4000 Japanese stone the Tormek version SG250 for a secondary micro bevel improved a lot the amount of time the edge remained sharp, but I still was not where I wanted.
I got an aftermarket 800 Japanese stone and now I am tempted to change my occupation from "wooder" to "sharpener". All my bevels now are looking as they were before and the big difference is the edge stays as when I was using the manual version to sharpen my tools.

... with this settings all my search for getting always a perfect sharp edge VERY FAST, is over.
Ionut"

[Jan]

Thanks Wootz for the info about availability of alternative grindstones for Tormek and also for your selection of great Ionut's quote. You have opened very interesting topic. 

I fully agree that the graded SG Tormek grindstone is not equivalent to real 1000 grindstone. Especially when sharpening fast, using the graded grindstone, we create deep scratches. It is known, that the surface structure of the metal is disturbed to a depth, which is much greater than the depth of the visible scratches.

My understanding, why the edge stays longer sharp when sharpened on finer grindstone is following: deep scratches in the metal surface, caused by low grit stone, can serve as stress risers, which can initiate fatigue cracks or some other  defects near the edge surface.



The movement of material along slip planes caused the extrusion of the metal surface.

Jan

[Ken S]

I remember when Ionut originally posted the topic. As I think highly of Ionut, I purchased one of these wheels. It is indeed less coarse than the ungraded SG wheel. This is both an advantage and a disadvantage. I found it slower than using the SG wheel. Yes, no time is lost by regrading the stone. However, the wheel has no coarse properties.

As I recall, the wheel was slightly oversize. It was a minor nuisance. The wheel also fit the bore very tightly. Changing wheels would not be convenient.

I was one of a number of forum members not keen on grading the grinding wheel. I decided I was not really a position to have an opinion on this until I became more fluent with the stone grader. I have reached the conclusion that if someone really wanted to avoid using the stone grader, the solution is two wheels, each mounted in its own Tormek.

Does the time saved make having two Tormeks cost efficient?

Ken

[Ken S]

Jan's post came in as I was preparing mine. What steps can we take to approach the ideal?

One recent modification in my technique is based on a suggestion Stig made. With all stages, I use lighter pressure for the last few seconds. This makes the scratches shallower.

For those of you who like to tinker, I have had good results using valve grinding compound with the leather honing wheel. My initial observations lead me to think that this could substitute for using the stone grader in many situations. VGC cuts more agressively than Tormek honing compound. Please note that it does not leave as polished finish as the Tormek compound. If you want to use both, a spare leather honing wheel is much less expensive than anyone's grinding wheel, and isvery fast to change.

I do not see the 800 grit wheel as a replacement for the SG wheel. I do see possibilities as an auxilliary wheel for advanced users. Consider it when you are working on you second SG.

Ken

[Jan]

Ken, do you have some experience with sharpening HSS using the 800 grit grindstone?

Jan

[Ken S]

Jan, sorry. I used the 800 grit on a couple chisels. I was not really impressed, so it has been in the box ever since. I don't work much with high speed steel.

Ken

[Herman Trivilino]

At 40X magnification, as I've mentioned before, the finely-graded Tormek SG grindstone leaves visible scratches in an edge. Honing on the leather wheel polishes the regions between the scratches.

While Jan likely has a point about these scratches causing fatigue and shortening the life of an edge, they also add a "tooth" to the edge that is an advantage for many cutting and chopping tasks in the kitchen and elsewhere.

I have a mild curiosity about how an edge ground with a dedicated Japanese Water Grindstone would look at 40X. But the price is too high for me to justify satisfying that curiosity.
 

[jeffs55]

Herman, I have long had a 4000 grit Japanese water stone and used it sometimes. I say sometimes because I regard it as more of a polishing stone than an actual sharpening stone. The instructions or maybe not them but something I read on the internet suggest that you do not need the leather honing wheel when using this stone. Indeed, it is almost like glass. I am going to order a 40x loupe right now, it is less than $5 on eBarf. Though not scientific quality, it might answer your questions.......................and mine. When it arrives, I will do some photographing and we will see what happens. I have a Canon 100mm macro lens that hopefully will do the job. Be patient as this might take a while.

[Herman Trivilino]

The instructions or maybe not them but something I read on the internet suggest that you do not need the leather honing wheel when using this stone.

I believe that's the Tormek recommendation.

[Ken S]

That is correct.

Ken

[wootz]

True if using Tormek honing compound.
Japanese Industrial Standards (JIS) 4000 grit is 3 micron particles, and Tormek Honing Compound consists of 1-3 micron particles, effective 3 micron.

However, extra sharpness can be achieved by honing with Chrome Oxide, which is 0.5 micron.
So, after SJ, I hone the blade on the Tormek honing wheel loaded with Green Rouge, and this invariably gives a sharper edge.
For harder steels, I also have to add a few puffs of 100,000# (0.25 micron) diamond spray over the honing wheel already covered with Chrome Oxide.

For example, I could never achieve hair splitting sharpness with SJ 4000 alone, shaving - easy, but as to the hanging hair test, the best I got was 'violin', but even that not always.
After honing with Chrome Oxide, hair splitting is a usual result.

In the "Experiments on Knife Sharpening" by John D. Verhoeven, in the chapter "Experiments with the Tormek machine", honing on the chrome oxide loaded leather wheel produces 0.35 microns edge as shown by scanning electron microscope.
The human hair cuticle is about the same thick, and a blade that sharp whittles a human hair lengthwise.

(Hanging hair test is detailed here http://straightrazorplace.com/srpwiki/index.php/Hanging_Hair_Test,_from_trick_to_probing_method#Controversy.3F)

[grepper]

Whilst hair splitting sharpness is very super cool, don't get me wrong, unless you are trying to make razors, cell pokers for gene experimentation or just the shear joy and understanding of achieving it, that type of ultra sharpness dulls quickly when suffering everyday use such as with kitchen knives. 

With that ultra sharpness the edge is so thin it is comparatively weak compared to a knife that is just good and sharp.  The joy of watching the knife slice through a butternut squash under nothing more than its own weight is indeed rewarding but repeatability before it dulls to just really sharp is so ephemeral it's rarely worth the extra effort

[wootz]

"...cell pokers for gene experimentation "  bugagaga

Can't argue that, it's definitely not for professional high volume work.
I do the full sequence for collector's knives though.

And sadly true that "repeatability before it dulls to just really sharp is so ephemeral" even with the high-end steels.

[grepper]

Wootz sayeth: "I do the full sequence for collector's pieces though".

I'll bet that if you exacting such care with your work,  the result is truly beautiful and impressive!

[wootz]

Wootz sayeth: "I do the full sequence for collector's pieces though".

I'll bet that if you exacting such care with your work,  the result is truly beautiful and impressive!

...yeah, and equally impractical.
One of many unnecessaries people do for "shear joy and understanding of achieving it"

Enjoyed your comment, thank you for good laugh