Charting Shapton stone lines

[Mr.Wizard]

Shapton has introduced the Rockstar line of stones apparently using a different grading than their classic offerings, as tabulated below. I am uncertain how to handle this for a future revision of my grit chart.

I could add yet another column but I think the chart is already at risk of becoming unwieldy. Perhaps I should average the Classic and Rockstar values, since it seems at best they are rough approximations given the finding of ridiculously out-of-grade particles in the 8000 Glass Stone stone by Todd Simpon. Or perhaps based on that finding I should "bite the bullet" and despite their popularity drop them from the chart entirely.

Please share your thoughts and advice on how best to proceed.

Grit	Classic	Rockstar
120	122.5	-
220	66.82	-
320	45.94	40
500	29.4	25
1000	14.7	11
2000	7.35	6
3000	4.9	4
4000	3.68	3
6000	2.45	2
8000	1.84	1
10000	1.47	NANO
16000	0.92	NANO
30000	0.49	-

 

[1315]

I wasn't aware who's chart that was. THANK YOU! It's been my favorite reference, and I've enjoyed using it.
My votes:
1. Keep the original chart "as is", since RockStar isn't even established yet (meaning will buyers accept it over the classic lines). I'd not add it until it's mainstream.
2. Can Rockstar replace another column that is perhaps obsolete now?

Thanks again for that work!

 

[More_Gyutos]

Wait, but are they not just thick Shapton Glass stones?

 

[labor of love]

Wait, but are they not just thick Shapton Glass stones?

Yeah I believe they’re simply thicker with no glass backing (someone please correct me if I’m wrong)
The question for me is how do I keep a 3-4mm worn down rockstar in place on my stone holder/sink bridge? Looking forward to a diy backing someone here makes to solve this problem

 

[Mr.Wizard]

Wait, but are they not just thick Shapton Glass stones?

Then the overly-precise micron values on Glass stones are to be considered deprecated, and the new values replace them?

 

[More_Gyutos]

Then the overly-precise micron values on Glass stones are to be considered deprecated, and the new values replace them?

I do not understand the intricacies of your question or the differences in the grits enough to answer.

 

[Mr.Wizard]

I do not understand the intricacies of your question or the differences in the grits enough to answer.

Pardon my lack of clarity, I wasn't asking anything technical. Your understanding is that the values given for the Rockstar line also apply to the Glass Stone line as they are actually the same stone? This is just a "new and improved" way of labeling the existing formulations?

The FAQ says "The RockStar series comprises 10mm solid sharpening stones of a high quality equivalent to those in the GlassStone series." But because of the different micron values I interpreted "equivalent" loosely.

 

[Tekkz]

Interested to see where this goes. I thought Rockstar was simply a double thick SG without the glass.

 

[Cliff]

Yeah I believe they’re simply thicker with no glass backing (someone please correct me if I’m wrong)
The question for me is how do I keep a 3-4mm worn down rockstar in place on my stone holder/sink bridge? Looking forward to a diy backing someone here makes to solve this problem

Isn't it possible to just buy the glass on Amazon and glue it?

 

[labor of love]

or maybe just wear down your shapton glass stone and reuse the glass backing by attaching to a rockstar stone?

 

[Cliff]

or maybe just wear down your shapton glass stone and reuse the glass backing by attaching to a rockstar stone?

Now that's efficient!

 

[labor of love]

There’s some serious DIY experts on this forum and I am not one of them. However I will gladly follow whatever idea someone comes up with. Those rockstars look quite inexpensive so I’m tempted to drift over to that line after my SG wear down.

 

[rickbern]

They seem to have just rounded the grit sizes per this chart​

​

Standard models​

320	40 micro class / TYPE WA	60315
500	25 micro class / TYPE WA	60116
1000	11 micro class / TYPE WA	60216
2000	6 micro class / TYPE WA	60316
3000	4 micro class / TYPE WA	60416
4000	3 micro class / TYPE WA	60117
6000	2 micro class / TYPE WA	60517
8000	1 micro class / TYPE WA	60217
10000	NANO class / TYPE WA	60917
16000	NANO class / TYPE CA	60317

Here’s their faq

What does 'class' refer to?​

It indicates the approximate median particle diameter (size) of the abrasive material in the product, in micrometres.
When expressed in words rather than numerically, 'COARSE' represents the largest median particle size class, and 'NANO' the smallest.

And to close the loop…

What does 'type' refer to?​

It indicates the type of abrasive contained in the sharpening stone.
HA: Mono-crystalline fused alumina
PA: Pink alumina
WA: White alumina
A: Regular (brown) alumina
CA: Calcined alumina
HPA: High purity alumina

 

[M1k3]

Yeah I believe they’re simply thicker with no glass backing (someone please correct me if I’m wrong)
The question for me is how do I keep a 3-4mm worn down rockstar in place on my stone holder/sink bridge? Looking forward to a diy backing someone here makes to solve this problem

Epoxy it to an old cheap diamond plate?

 

[Mr.Wizard]

They seem to have just rounded the grit sizes per this chart

That's the chart I copied the Rockstar values from. A rounding rule does not appear obvious to me.


Looking more at these values I realize they are congruent to JIS R 6001, with the exception of 2000 which is slightly too fine. I believe this is also the first place that Shapton has declared their micron grades as "approximate median particle diameter." If these values apply equally to the Glass Stone series the Shapton column is essentially rendered redundant.

 

[More_Gyutos]

Pardon my lack of clarity, I wasn't asking anything technical. Your understanding is that the values given for the Rockstar line also apply to the Glass Stone line as they are actually the same stone? This is just a "new and improved" way of labeling the existing formulations?

The FAQ says "The RockStar series comprises 10mm solid sharpening stones of a high quality equivalent to those in the GlassStone series." But because of the different micron values I interpreted "equivalent" loosely.

No, I didn’t know what you meant by “Classic”. I am familiar with Glass stones in use and Kuromaku only slightly, so when you presented your question I wasn’t sure if Classic referred to the glass series and further, why Rockstar would be different considering I understood it to be the same as for the glass stones, only double in thickness.

 

[Mr.Wizard]

This guy thinks the RockStar is different from the GlassStone. I guess I need to wait for more feedback on these.




B&B member thinks the rating is backward, with the 3 micron RockStar acting coarser than the 3.68 micron GlassStone.

Steve56​

Based only on the 3u/4k Rock Star, it is not as fine as the 3.68u/4k Glass Stone HR. My bevel set test is actually HHT after 10 linen/20 leather after 4k (or 5k). A decent razor will HHT quite well off the 4k GS while the same razor will struggle to HHT off the 4k Rock Star. I’ve tried this with multiple razors, but it is with just one stone. It does however, fulfill the same function and I probably never would have noticed the apparent difference if my first RS hadn’t been a 4k.

 

[stringer]

This guy thinks the RockStar is different from the GlassStone. I guess I need to wait for more feedback on these.




B&B member thinks the rating is backward, with the 3 micron RockStar acting coarser than the 3.68 micron GlassStone.

He is on here too same handle. @Steve56

 

[Steve56]

I’ve hd a lot more steel, both razors and knives across the Rockstar 4k. I think that it’s probably closer to the 4k HR Glass than my original assessment, though I still think that the RS ’acts’ a tiny bit coarser than the 4k Glass Stone.

It’s close enough to not matter really, the only reason that I noticed is that my personal bevel set test for straight razors is to test the Hanging Hair Test after the 4k stone and a light stropping - if it passes silent HHT the bevel is perfectly set. I can tell the difference in HHT with the 4k GS being a bit better, but in a razor progression or for knives and tools, it won’t make any difference.

The one thing that Shapton says is different is that the Rockstar series is more wear resistant, and that means the binder is different, and a stone with the same grit but a different binder may very well act differently. I can say that the 4k Rockstar makes a beautifully consistent scratch pattern.

And for 10mm of abrasive for $45, I’ll take two.

Hope this helps

Steve

 

[1315]

Rickberns Standard Model chart above will be the new micron ratings for both Glass and RockStar, says Shapton, making a NEW micron and corresponding grit ratings in the GS and RS the same. Glass came out 20+ years ago, and Shapton is "correcting" the micron rating by measuring with new technology , therefore giving consistency between micron and grit ratings in the GS and RS series. Glass backing will soon sport a new design, which will have the corrected grit rating (so there will be "old" and "new" stones for us users) and the new look will be this:

 

[Mr.Wizard]

Rickberns Standard Model chart above will be the new micron ratings for both Glass and RockStar, says Shapton, making the micron ratings in the GS and RS the same. Glass came out 20+ years ago, and Sharpton is "correcting" the micron rating by measuring with new technology , therefore giving consistency between micron and grit ratings in the 2 series. Glass backing will soon sport a new design, which will have the corrected grit rating. It will look like this.

Thank you for getting this!

With this confirmation that the new values do apply to the GlassStone series, I am thinking that it is now sufficient to annotate that Shapton is congruent with JIS R 6001, other than the minor deviation of 2000 as noted earlier. The GS/RS lines do not even have identifying colors to argue for their inclusion on that basis.

 

[stringer]

Thank you for getting this!

With this confirmation that the new values do apply to the GlassStone series, I am thinking that it is now sufficient to annotate that Shapton is congruent with JIS R 6001, other than the minor deviation of 2000 as noted earlier. The GS/RS lines do not even have identifying colors to argue for their inclusion on that basis.

You are the man @Mr.Wizard. Thanks for keeping this thing up to date all these years. It's an invaluable resource to the community.

 

[rickbern]

I actually looked a bit more into this and went ahead and bought the 2000&4000. I may have been wrong about the similarities to the glass series.

The glass series has 14.7 stamped on the 1000 grit stone and the rockstar is calling 1000 “11 micro class” there seems to be a fair bit of variation at this grit. The other low grits seem to stray from the old standards as well.

We always thought the 1000 was coarser than the competition, maybe they fixed that.

 

[1315]

But that's the "old" glass stone. "New" glass will have the revised microns, and should be the same as the black RockStar microns and grits

 

[SammieM]

Funny thing is that Shapton doesn’t actually say “micron” it says “micro”. I don’t think they are truly 1 micron or 3 micron. I think it is a play on words… I might be completely off the reservation, but @Steve56 testing can be viewed as confirmation… Again, I don’t have any official confirmation and a leg to stand on, but this is some food for thought…

 

[Justinv]

Mine says micron on the back. I checked a 2yr old one and a 10yr old one.

 

[SammieM]

Mine says micron on the back. I checked a 2yr old one and a 10yr old one.

This is from the Shapton site. All the way to the 8k it says “micro”. Are you talking about the regular GS? I was referring to the Rockstar…

 

[Mr.Wizard]

Rickberns Standard Model chart above will be the new micron ratings for both Glass and RockStar, says Shapton, making a NEW micron and corresponding grit ratings in the GS and RS the same. Glass came out 20+ years ago, and Shapton is "correcting" the micron rating by measuring with new technology , therefore giving consistency between micron and grit ratings in the GS and RS series.

Do you have any idea when this change may take place? My current draft preserves the existing Shapton data, adding the annotation "Not applicable to RockStar." I would like to release soon but if this change is about to happen I may wait to better address it.

 

[1315]

Pm'ed

 

[Mr.Wizard]

I see that Shapton.co.jp has been updated, the Glass Stone line has the new markings, and the FAQ includes:

Recent GlassStones look different from the designs bought in the past. Is there any difference in spec?

No. The only change was in the printing design, not in the quality or specs of the stones. Click here to see the before and after designs.

I had an inkling that the change in marking might be accompanied by a change to JIS R 6001 compliant composition, given the nearly perfect alignment of values, but explicitly it is not.

I really don't know what to do with Shapton values at this point. The stones do not appear to comply with their own definitions in the FAQ unless we stretch "approximate" to the breaking point, or Todd Simpson simply had a defective sample.

What does 'class' refer to?

It indicates the approximate median particle diameter (size) of the abrasive material in the product, in micrometres.

I do not see how the Glass Stone 8000 can be of "class: 1 micro" as defined above while being filled with figurative boulders as seen below in Todd Simpson's SEM micrographs.