Thread: Suehiro Gokumyo 20K

Originally Posted by kelbro

For those $$$$ if it wasn't flat, I would be sending it back.

It might have been flat when it was boxed up at the factory, lots of factors that will change it.
Humidity, how much water you soak it with, or don't soak. how you dry it, not dry it. how you store it.

Synthetic stones do go out of flat, I always run mine over a DMT a few laps every couple razors. Doesn't matter the brand, I own them all and same problem on all (p.s. other than shapton glass)

I've had the Gok 20 for a long time now. When I got it, I checked it for warping (Both sides) and generally checked it with a straight edge and feeler gauges. Mine was fine, but I lapped it for 15 minutes on the non-print side, just to disrupt the surface a bit and prep it for some honing. I used an Atoma 400. I have lapped it only twice in over 18 months. I have about 35 razors, but can only shave with one a day...lol So my Gok 20 doesn't get used heavily. As Oz said, it'll cost $50 to post it back, when all they will do when they get it back is hone the dip out of it and return it. It is worth re-iterating that the Gok 20 is a bloody hard stone, and even after 15 minutes on the Atoma 400 it gave up very little, only sufficient to wipe off the bit of pencil I squiggled on it.

Originally Posted by onimaru55

Nope you're wrong. My Atoma 1200 was brand new. That I had to start with 80 grit SiC on glass should make it obvious how warped my stone was.

Yes, obviously a hone shaped like a banana will take longer than one that is nearly flat. This would be the case for any diamond plate. My comparison was based on two hones that were out a normal amount that's usually the case for maintenance lapping. I should think it would be obvious that a 1200 grit plate would not be the optimal tool for the large amounts of material removal that would be required with a hone that's substantially out from flat.

Originally Posted by mainaman

No stone will come flat out of the box, ever.

Understood but I'm talking gross, as one was described a banana shape.

Originally Posted by onimaru55

And spend another $80 posting it back ? Really ?

Yeah, that's unfortunate that you have to pay that kind of shipping but if I received one that was grossly mis-shaped I wouldn't be paying the postage back. I would be charging the credit card back and you can bet they would send you a pre-paid shipping label then.

Been thinking about this 1200 stripping diamonds on the 20k. Going by the unfortunate experience of Sham with his DMT 1200 (which Dia-Sharp did replace BTW) I was figuring that because of the different construction of the Atoma it was probably alright to lap waterstones.

Dia-Sharp specifies (after the problem with Sham's) no higher grit than 325 and that under running water. Before Sham posted his warning I was using a DMT D8C 325 at home, and a DMT 1200 at work. I noticed that the Norton 4 had grey streaks on it when I lapped it with the 1200. Curious. Fortunately Sham posted his experience and I realized the grey was the diamond and substrate nickel stripping off of my plate. I say fortunately because I hadn't ruined the thing.

So...... cutting to the chase .......... if the 1200 isn't good for lapping the 20k, is it alright for other waterstones ? I realize the 20k is super hard. The next question ........ if the 1200 will strip diamonds on the 20k, what plate won't ? Maybe I'm stuck with the loose grit on a ceramic tile ? If I had it to do over I'd just stick with the Naniwa Superstone and the hell with it.

I've looked at the 20k under magnification and it appears okay. Going by the aforementioned experience with the grey streaking on the DMT I note that I've seen none of that on the 20k. I've always lapped under running water, and always the tail end of the job. So maybe I've dodged the bullet. Examining the plate (magnification) the diamonds are consistent, and not badly worn.

Makes sense that the finer the diamonds the more difficult it is to anchor the little beasties on the plate. So goes without saying high grit diamond plates are fragile to begin with and treating them to rough will ruin them. That said I do dress my SG-20k with a trend 1K diamond plate but with very light pressure being mindful of the possibility of disaster. As Mainaman mentioned its just being used to smooth out the marks made by the rougher 300 plate and in no way is taking a role in lapping the stone. I have been lucky so far I guess but lapping a Suehiro for me is just not done that often.

I fully understand the reasons for using the Atoma 1200 on the Suehiro Gokumyo 20k. When I 1st got it, I used the Atoma 400 and I didn't like the striations it left on this supposedly 'Finest' hone, so i ran it over some 1500 wet/dry. It worked fine, but I decided then to buy an Atoma 1200 so I could maintain what I believed was a better finished hone. Thats where Tools of Japan came in. Now many members know Stuart, and he doesn't mince words, and when I sent an email to obtain a Atoma 1200 from him, he said,(I won't sell it to you if your going to lap the G 20K with it), so I have since then (Over a year ago) I've mentally ignored any stria from the 400 and haven't had an issue with the result, it gives the same great edge as it did after 1500 w/d which also is banned. So guys, put a mental blindfold on and use the DMT 325 or the Atoma 400. Once you cross the mental battle it's plain sailing from there.Every couple of razors on the G20 I give it a half a dozen figure 8's with the 400 just because I believe that a slightly disrupted surface gives me a better result.

Originally Posted by bobski

I fully understand the reasons for using the Atoma 1200 on the Suehiro Gokumyo 20k. When I 1st got it, I used the Atoma 400 and I didn't like the striations it left on this supposedly 'Finest' hone, so i ran it over some 1500 wet/dry. It worked fine, but I decided then to buy an Atoma 1200 so I could maintain what I believed was a better finished hone. Thats where Tools of Japan came in. Now many members know Stuart, and he doesn't mince words, and when I sent an email to obtain a Atoma 1200 from him, he said,(I won't sell it to you if your going to lap the G 20K with it), so I have since then (Over a year ago) I've mentally ignored any stria from the 400 and haven't had an issue with the result, it gives the same great edge as it did after 1500 w/d which also is banned. So guys, put a mental blindfold on and use the DMT 325 or the Atoma 400. Once you cross the mental battle it's plain sailing from there.Every couple of razors on the G20 I give it a half a dozen figure 8's with the 400 just because I believe that a slightly disrupted surface gives me a better result.

I just wonder if the coarser grits on the plates might not suffer the same 'stripping' of diamonds & embedding in the surface of the 20k. Also irritated that there is nothing on anyone's website that warns anyone of this possibility. I'm going to email Stuart and ask him about this, and about my cracked Chosera 10 & 5K. Not a happy customer.

Originally Posted by JimmyHAD

Been thinking about this 1200 stripping diamonds on the 20k. Going by the unfortunate experience of Sham with his DMT 1200 (which Dia-Sharp did replace BTW) I was figuring that because of the different construction of the Atoma it was probably alright to lap waterstones.

I have found this to be the case & I lap harder stones than the 20k. In fact when I first met So & he suggested these plates to me, he had used his already for 7 or 8 years on his Jnats.

Dia-Sharp specifies (after the problem with Sham's) no higher grit than 325 and that under running water. Before Sham posted his warning I was using a DMT D8C 325 at home, and a DMT 1200 at work. I noticed that the Norton 4 had grey streaks on it when I lapped it with the 1200. Curious. Fortunately Sham posted his experience and I realized the grey was the diamond and substrate nickel stripping off of my plate. I say fortunately because I hadn't ruined the thing.

So...... cutting to the chase .......... if the 1200 isn't good for lapping the 20k, is it alright for other waterstones ? I realize the 20k is super hard. The next question ........ if the 1200 will strip diamonds on the 20k, what plate won't ?
As above.
Maybe I'm stuck with the loose grit on a ceramic tile ? If I had it to do over I'd just stick with the Naniwa Superstone and the hell with it.

Flattening stones of differing warp requires different tools. SiC on glass etc is easy & effective. For daily maintenance & slurry making I use the 1200 Atoma on all stones 8k & up.
Below that, ie 1k-5k I use my 400. For my 320 Pro I use a 140 Atoma. I would not use a 1200 Atoma on a 1k stone any more than setting a bevel on a razor with a 12k stone.
Horses for courses.

There is one stone that will destroy most diamond plates in short order & that is the Spyderco UF. 2 mins max with a 1200 Atoma will see it adequately "broke in" beyond that , well, its your plate .

I've looked at the 20k under magnification and it appears okay. Going by the aforementioned experience with the grey streaking on the DMT I note that I've seen none of that on the 20k. I've always lapped under running water, and always the tail end of the job. So maybe I've dodged the bullet. Examining the plate (magnification) the diamonds are consistent, and not badly worn.
I think that says it all.

~~~~~~~~~~~~~~~~~~~~~~

Jimmy, you'll find Stuart has dealth with this a few times, and from memory it is the fact that the finer clusters on the 1200 are more likely to break off, thus embedding in the stone. Why they do it I don't know, but I do believe he is of the view that don't use it (1200) on any stones. I think it becomes more apparent on a stone the hardness of the G 20. As I mentioned mate, I am not a heavy user of the G 20 as a hobbyist, but I only became aware of the issue when I tried to buy a 1200 off him thus the warning. Cheers Bob

Forgive me Jimmy, what went wrong with your choceras, I have a couple I use the Atoma 400 on?