Shapton G7 Update

Gents,
I purchased a set of the new Shapton Glass G7 stones several weeks ago and all were fine except the 0.44 micron (>30k). That stone felt gritty and left a scratch pattern more like a 500 grit than a 30k, and I could see where particles had come out of the matrix under 7x magnification. I sent it back to Mark at CKTG, and he returned it to Mr Ishida at Shapton in Japan.

Mr Ishida’s remarks are worth posting, not because I believe that he’s describing the problem with my stone (it has to be a matrix issue, not a grit issue) but because it answers a lot of questions about the Glass series and why some stones are recommended for razors and others are not, and why some folks see coarse scratches and others don’t (maybe using different Glass stones?). They’re not all the same! I believe that it is appropriate for me to post the email text.

“Hello Mark san,

I received the defective G7/0.44. Thank you. I will check that stone. Meanwhile, I will send you the replacement.

By the way, I would like you to know that G7/0.44 should not used after G7/0.85. That is because the abrasive of 0.44 has wider tolerance than 0.85. As a result, 0.44 might leave larger scratch in comparison with 0.85. Please, see the attached. Actually, the center particle size of G7/0.85 is larger than G7/0.44, but the distributions of its abrasive size is more accurate than G7/0.44. Also, there is the same situation between GlassStone10000 and GlassStone16000. sometimes users wonder why GS10000 is more expensive than GS16000. This is one of the main reasons. In case of Mr. Steve Hamley, I recommend not to use 0.44 because he has 0.85. In addition, for straight razor sharpening, we usually recommend GS10000 rather than GS16000.”

Here’s the table from Shapton via Jende, it makes more sense in light of Mr Ishida’s comments above.

Great info to know and shave here, Steve. Odd that it is made this way. Im not an owner of glass stones, but if I planned on buying this would be a good chart to reference.

Thank you for the update! Had similar results, was driving me crazy! Testing different steels until I came up with the same conclusion. Not me something is up with the stone. Thanks for sharing.

Interesting. I used mine (.44) this week and thought it odd that it did not improve the scratch pattern from my translucent that I keep refreshed. I didn't have large scratches though. There I was thinking that my translucent was 30K+ !

Another example of where a great shave resulted from a scratch pattern that wasn't perfect.

Quite interesting. I have one of the Shapton Glass 16K stones, but I decided to forego the 30K stone and purchase a Suehiro G20K stone instead. I find it hard to believe that Shapton would ship a stone as expensive as the SG30K that has a wider distribution of particle sizes than the SG16K. That just does not make sense to me. If the SG30K is not good for razors, what would it be good for?

Having a distribution of particle sizes is not necessarily a bad thing unless there are some unsuitably large particles in the distribution. It is my impression that one reason many people love edges off natural stones is because the have a range of abrasive particle sizes. High grit synthetic hones tend to produce a very sharp edge with a nicely polished bevel. However, with some stones, the edge may be uncomfortable, especially if you overhone.

In contrast, some natural hones may not give quite the same level of polish, sometimes leaving the bevel a little hazy, but may give more comfortable edges.

I realize of course that these impressions are generalizations and do not apply to every synthetic or natural hone. There will be exceptions. I have limited experience with my Suehiro G20K, but it seems to produce keen, comfortable edges with a nice polish. I also know that some people produce highly polished edges with some hard Arkansas stones or JNats as well.

A while ago I ordered a 16K/50303 shapton hone and was surprised to find it left deeper stria on an already honed 12K Naniwa edge.

https://sharprazorpalace.com/hones/1...ria-bevel.html

The place I ordered the Shapton from even had a note saying the Shapton 16K was not recommended for straight razors and why.

https://www.paulsfinest.com/shapton-...ategory_id=120

Seems to confirm everything in this thread so far. Live and learn as they say.

Bob

What a PITA! Maybe it was God's provenance that I never bought shaptons. Lol.

I have read that before but my SG16K produced fantastic edges. I was not as thrilled with the 10K.