Japanese 800 grit wheel is now available from a German seller

[grepper]

"One of many unnecessaries people do for ""shear joy and understanding of achieving it""

Great craftsmanship generally results in not only personal satisfaction for the craftsman, but also, for those capable of joy and understanding, great beauty.  A life void of joy, understanding and beauty is a barren life indeed.

[jeffs55]

 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
NO knife unless it is of such a weight as to render it unusable by mere mortals will ever slice through a butternut squash of its own weight! Not even after baking it into a pile of slag will your knife slice through this skin under its own weight unless it meets the above criteria.

[wootz]

I understood butternut squash as a due sarcasm on obsession with super sharpness, bringing to mind other sharpness legends, like
-  katanas put upright in a stream should be able to cut cleanly through any leaf that floated down to touch the edge;
-  the knightly sword should be able to sever a human hair floating in the air;
etc

[grepper]

Well..., huh.  I guess my exaggeration therapy was a failure, even though I gave it 110%. 

[wootz]

Well..., huh.  I guess my exaggeration therapy was a failure, even though I gave it 110%. 

Mate, don't get me wrong, but there is no such thing as 110%

[grepper]

 

[Ken S]

Good humor!

I have a hobby interest in measurement, especially in machine shops. Inspection tools are more accurate than the tools used on the shop floor. The calibration tools used to check the inspection tools are even more accurate, and they are sometimes checked by the National Bureau of Standards. We should all be capable of creating keener edges than are usually required.

Ken

[wootz]

I got both SUN TIGER wheels for my Tormek-7: 800 grit out of necessity, and 4000 grit out of curiosity.
Now that I've had sharpened half a dozen knives on them, can share observations.

The SUN TIGER wheel diameter is 254mm.
The water trough fits almost flash, yet no brushing, no issues here.
I read Ken's concern that the wheel fits the bore very tightly, so as precaution before fitting the wheel I smeared the bore with a lanolin grease, but this was not needed with the wheels I got; I have no difficulty changing them.
The wheels had to be trued a little out of the box, but this is the case with standard wheels as well.
They soak up water slower, about 30 min.
I use KING Nagura stone for smoothing out after truing and for declogging the #4000 stone, and fine side of the Tormek grading stone for #800.

SUN TIGER 800 grit compared to finely graded SG
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.
Sharpening on SUN TIGER wheel is a symphony.
No shortcomings of graded SG mentioned in the beginning of this post: hard grading can untrue the wheel and get the corners out of square, also, with use, the graded SG gets rough spots where the original grain somewhat opens.
2 thumbs up for SUN TIGER

SUN TIGER 4000 grit compared to SJ
Not that unequivocal.
SUN TIGER is definitely denser, it won't flake on the corners when trued or declogged (while truing SJ often leaves ragged edge), doesn't clog as fast, and won't wear off as quickly.
However, SJ is finer.
SJ leaves perfect mirror surface, and doesn't require deburring/honing afterwards. After SJ I can't feel a burr with the thick of the thumb.
SUN TIGER 4000 leaves a palpable burr that must be honed away, and the resultant bevel is not as shiny.
I'd say SUN TIGER grit is 1000 JIS less than SJ.
As a sidenote, they say SJ grit is 4000, but from my experience with bench stones I'd grade it at 5000.

[Ken S]

Good preliminary testing, Wootz.

I really did not use my Tiger wheel enough to fairly comment. At the time, I was sharpening primarily chisels. Being 800 grit, it did not seem to cut as quickly as the SG graded coarse. That's understandable.

In considering the SG-250, it is only fair to remember that until November of 2008, the SG was the only grindstone for the Tormek. It was expected to work with all of the Tormek jigs and different kind of steel.It was expected to sharpen planer blades, including removing nicks. It was expected to reshape and sharpen turning tools, both carbon and high speed steel. It was expected so sharpen tools sized from small carving tools to axes. In conjunction with the leather honing wheel, it was expected to handle the whols sharpening process from grinding through honing and polishing. No dry grinding wheel, bench stone or sanding belt is expected to do so much.

In truth, the SG was not always a speedster at all of these things. Howbever, it did do them. It has also been expected to be long lasting. That's a tall order for any grinding wheel.

I am not surprised that the 800 grit wheel seems a useful adjunct for the Tormek. I have found the two Norton 3X wheels (46 and 80 grit) useful additions. Neither of the 3x wheels will ever be my general purpose wheel. They do help when I have a lot of grinding to do.

The SG grinding wheels are the old reliables which do most of my sharpening.

Ken

[Titian]

Always tempted by more sharpening stonez, I too could have been seduced to buy a dedicated 800 grit or 1000 gritsone, however I have discovered the effortless secret to grading the stone effectivley! The secret is to use cheap diamond sharpening/lapping stones to grade the Tormek wheel and I mean cheap the one I use cost me a few pounds plus I have a couple of lapping plates bought of ebay which again were much less than a tenner.

The diamond sharpening stone that I have has a 200 grit on ones side, Other grits I use are 1200 grit and 3000 grit. I find these give much better, faster and consistent results to the stone grader, very little pressure is used. It really takes very little effort and when changing to the 1200 grit (cause that's what I had) it gives a smooth surface. When I use the grader I always feel a few particles that have not been crushed that leave anoying scratches. Now I dont worry about changing grit when I need to, cause it's no trouble. Really I dont know why tormek stick with the stone grader I almost sold my Tormek because the results were so poor but it's was the stone grader. I'm sure some Tormek experts can use it but I get better results with cheap diamond stones. Most people who need to do some sharpening and have a tormek probably have some diamond stones lying around to give it a try.

Hope that helps someone.

[Jan]

Thank you Titian for sharing your experience and views. 

For me the whole grading/dressing procedure remains somewhat mysterious.
Your successful usage of the diamond sharpening stone may indicate that you are reliably reaching the necessary depth of dressing cut, while some users of the Tormek stone grader may cut too shallow.

I searched for recommendations concerning the depth of dressing cut and got a few and even more ambiguous results. 

The best reasoned guidance was to make the depth of dressing cut equal to 10 to 30% of the average grain diameter. For 220 grit stone the average grain diameter is some 0.07 mm and so the recommended depth of dressing cut would be 0.007 to 0.02 mm. To measure such a small changes is beyond our possibilities.

Interesting for me was finding a note that too large depth of dressing cut can result in lower grindstone performance caused by insufficient grains protrusion.

Jan

[Ken S]

Fascinating comment, Jan. I had not thought about the depth of the dressing cut.  I will now.

Ken

[Jan]

Thank you Ken, it's simply my way of thinking about "Why is it so? ". I am happy if I have inspired you. 

Jan

[Stickan]

As I understand this is that Titan is "polishing" the stone with a 1200 grid diamond stone which will flatten the stone and make a temporary 1000 grid stone.
It may take less time than using the SP-650 but new grids will appear as usual so it's a constant work if you need a very fine stone, as with the SP-650.
We believe the SP-650 works very well and it is design to work with all our stones.
What I have noticed is that many users are a bit to gentle using the stonegrader and therefore it takes longer time. I normally use the stonegrader 15-20 seconds to achieve the grid I want. And I always listen to the stone and visually check the result on my tool before going "All-in".

Best,
Stig

[wootz]

Further to my previous notes on the aftermarket stones for Tormek, a summary of experience sharpening knives on them for the last year.

In one sentence, SUN TIGER's grinding wheels for Tormek are good for conventional carbon and stainless steels, but will not grind high end tool steels, whereas Tormek's have no problem with the latter.

Tormek's Japanese SJ proved better than SUN TIGER's #4000 almost in every aspect; nothing to discuss.

#800 SUN TIGER's grinding ability is limited to mainstream carbon and stainless steels. It cannot grind wear resistant high end tool steels, in particular those with Vanadium content over 4%.
E.g. from my experience it struggled but still ground Latrobe CPM-20CV, and Bohler-Uddeholm M390 and Vanadis-4, but was useless on Vanadis-10, Vancron 40, S290, and CPM S110V.
Tormek's finely graded SG has no problem grinding any of them.

Physical make of SUN TIGER's grinding wheels concedes to Tormek's.
SUN TIGER's wheels have pronounced lateral wobbling.
SUN TIGER's are softer and easily chip off, therefore truing any of them you have to take the same precautions you usually take only with Tormek's Japanese SJ.

All that said, last month I ordered another #800 SUN TIGER's grinding wheel as you can't beat the advantage of a dedicated fine stone.