I am always careful to lap with water that is close to room temperature. It’s tempting to use warm water but a temperature gradient across the stone or metal plate can warp them.
Naniwa 12k warp ?
- Thread starter luv2shave
- Start date
I backed mine with glass. I used Devon 2 ton epoxy. I also frosted my glass with Silicon carbide powder (just like the Shapton glass) and beveled/chamfered the sharp edges and rounded the corners with a belt sander. Mine stays stable. Devcon is good stuff, its gap filling and dries clear and does not shrink, be sure to lap stone flat before bonding the one side to the glass . YoU got ti act quickly even though its 30 stuff you only have about 15 min, to line everything up. Its not a fast process and it wasn't easy the first time, but it gets better as you do more stones. I actually clamped two levels to the Tabletop and made a 90° so i could line everything up square.I have been using my 4 year old Naniwa 12k more extensively than before as I hone two or three razors per week. A gold dollar or an ebay razor on any day to practice my honing
My final stone is the Naniwa 12k where I do about 20 laps per razor.
After I put the stone away and take it out a day or two later for use, I lap it with the diamond DMT coarse plate as recommended.
Being a splash and go , I lap it under a small trickle of tap water.
The stone seems pretty warped and needs considerable work to get flat again in the center. It's frightening to see so much warp and the amount of stone which needs to be lapped away from the two ends
Is this normal considering I hardly do 20 laps or so on it at a time and put it away.
No such issues with the chosera 400 or 1k considering they get used much more per session, the soaked 4k/8k Norton also seems flat needing minimum lapping.
Any inputs appreciated.
I glued my 8k super stone to slate. This solved the problem just fine.
I did not get this far with my 12k. I dropped it by accident. It split in half. Warping issues solved
I was considering replacing it, but i found out that i did fine with a smaller stone. I was only doing a few short strokes on that thing anyway. After an 8k, you really do not need to do much on an 12k.
I did not get this far with my 12k. I dropped it by accident. It split in half. Warping issues solved
I was considering replacing it, but i found out that i did fine with a smaller stone. I was only doing a few short strokes on that thing anyway. After an 8k, you really do not need to do much on an 12k.
I have a jns 6000 and it also warps. I also have a theory.
When you thickness-plane wood for construction, you do one pass, flip the piece, do a pass, and continue like that until you have the desired measurement. Theres other tekniques i guess, but the thing is you want to plane an equal amount on each side to prevent movement in the wood...
...and like the warping issue, when i come to think of it i only use one side of the hone, and therefore only flatten on on side.
Ok, so stones dont have grain like wood and perhaps the only thlng that connects them are the shapeshifting thing and nothing else. Please chime in here
When you thickness-plane wood for construction, you do one pass, flip the piece, do a pass, and continue like that until you have the desired measurement. Theres other tekniques i guess, but the thing is you want to plane an equal amount on each side to prevent movement in the wood...
...and like the warping issue, when i come to think of it i only use one side of the hone, and therefore only flatten on on side.
Ok, so stones dont have grain like wood and perhaps the only thlng that connects them are the shapeshifting thing and nothing else. Please chime in here
Most stones don't warp and most stones are lapped on one side only.
FWIW - I have lapped the 10mm Super Stones on both sides and they warped.
My 20mm 12k was warped, new, in the box; was lapped on both sides, and still warped afterwards.
I suspect it has to do with uneven baking during the manufacturing process. That is a 'thing' that Naniwa has been dealing with since forever.
I also think uneven drying is part of the story.
FWIW - I have lapped the 10mm Super Stones on both sides and they warped.
My 20mm 12k was warped, new, in the box; was lapped on both sides, and still warped afterwards.
I suspect it has to do with uneven baking during the manufacturing process. That is a 'thing' that Naniwa has been dealing with since forever.
I also think uneven drying is part of the story.
Yeah it was a longshot.
The only naniwa I have that warped is my 10mm 12k that I fixed by epoxying to a ceramic tile. I have an 800, a 2k, and a 8k Lily White, and no problems with any of them. Only the 12k.
~doug~
i usually just lap it and use it. i do the grid marks nearly every time i lap it or ill lap it till all the swarf is gone if im on a bit of a time constraint. ive gotten great edges from it but i do find it easier to get flat in my opinion, after each session. i am by no means a great master of honing or of wet shaving but it works for me so take what i say with a grain of salt peace
peaceI think you mean Snow White, not Lily White.
I'm sure someone out there has owned Nanis and never had an issue.
But Naniwa stones Warping, crazing, and cracking has been an issue for a long time.
I've had several full sets of Super Stones and Specialty Stones - no issues until about 5 years ago when I first saw warping. My first two sets of Super Stones were problem free for the time I owned them.
Around 5-6 years ago, several Chosera/Pro stones were starting to craze and crack.
Following that, several Super Stones and Speciality Stones proved to be unusable due to warping.
Never had issues with either Snow White, the 4k Finishing stone, Falcons and Fujis. The Arata and Hibiki were fine too.
If I had to guesstimate, probably 15-20% of the Nani's I've owned had catastrophic issues.
Regardless of the Even so - I have have had too many Naniwa stones with issues.
Yes, I meant Snow White.
One stone warping is too many. At least I wont have to worry about any of my arks warping.
~doug~
I live in a pretty dry area with low humidity year round and I have constant issues with my superstones warping. I have the Gouken Kagayaki 5k and 12k 20mm which is the Japanese domestic version of the superstone according to Naniwa directly as well as the actual Superstone 8k in 10mm. I glued the 10mm version to a tile and it still seems to move constantly. I legit thought I was going crazy because i'd lap my stones, put them away and they were bellied the next time I went to use them.
I'm sure some of you have heard of the Gesshin line of stones from Japanese Knife Imports, they're mainly splash n go stones but there is a resinoid version. This is what Jon states in his description "Resinoid based stones are not very porous, which often causes them to be marketed as splash-and-go. However, some water does soak in. My preference is to soak this stone permanently, as soaking helps soften the stone, increases cutting speed, and reducing loading on the stone surface. If you do soak the stone, or if you think any water has soaked in, and you decided you want to dry the stone out for any reason, you will need to make sure the stone dries as slowly as possible, to help make sure the outer part of the stone does not dry more quickly than the inner part of the stone. Making sure the stone dries in a cool, well ventilated, dry area, out of direct sunlight is best. It also helps to wrap the stone with a damp towel to slow the drying process further. If unaccounted for, drying too quickly can cause cracks to develop in the stone. If cracks do develop, mounting the stone to a base can help extend the life of your stone."
The Superstones are also resinoid based, I figured all resinoid stones must be at least similar in properties. I wanted to see if I could permasoak the superstones too and hopefully stop or help the warping issue since the warping seems to happen when the stones dry out. I emailed Naniwa and they gave the generic "its a splash n go stone" answer and directed me to email a US vendor for further help. I emailed the vendor and they gave me the same answer along with "stones shouldn't warp". I finally emailed Jon from JKI directly and asked him. That night before Jon could answer I decided to put my 5k in with the rest of my permasoakers, I got it for $40 I can live with it if it cracks.
I got a reply from Jon and he stated he has permasoaked the Naniwa Superstone line or at least has experience with it and has had positive results. He recommends once you start permasoaking them they should always stay that way, If you're going to dry them dry very very slowly.
My 5k has softened some and it definitely cuts quicker than before and seems to load a little less but more importantly it went in flat and it has stayed that way, no warping. I am going on a full week of permasoaking the 5k with no issues so far. To test my 8k and 12k I wet them down then wrapped them in a wet paper towel and put them in a plastic bag to keep the stones wet for 24 hours to see if they will get gummy / start getting super soft, they didnt. I ended up putting my 8k and 12k in with the rest of the permasoakers on Saturday this week. Yes there is a chance the stones can start to deteriorate and fall apart, Jon made that clear, but at this point they warp so bad they feel borderline useless anyways so Ill be the guinea pig.
I was going to share my experience with you all in a new post but I ended up stumbling on this thread out of nowhere and decided this would be a good place to share. Ill update you all as time goes on if you'd like but for now the permasoaking.
Sorry for the essay, I hope this helps someone out there.
I'm sure some of you have heard of the Gesshin line of stones from Japanese Knife Imports, they're mainly splash n go stones but there is a resinoid version. This is what Jon states in his description "Resinoid based stones are not very porous, which often causes them to be marketed as splash-and-go. However, some water does soak in. My preference is to soak this stone permanently, as soaking helps soften the stone, increases cutting speed, and reducing loading on the stone surface. If you do soak the stone, or if you think any water has soaked in, and you decided you want to dry the stone out for any reason, you will need to make sure the stone dries as slowly as possible, to help make sure the outer part of the stone does not dry more quickly than the inner part of the stone. Making sure the stone dries in a cool, well ventilated, dry area, out of direct sunlight is best. It also helps to wrap the stone with a damp towel to slow the drying process further. If unaccounted for, drying too quickly can cause cracks to develop in the stone. If cracks do develop, mounting the stone to a base can help extend the life of your stone."
The Superstones are also resinoid based, I figured all resinoid stones must be at least similar in properties. I wanted to see if I could permasoak the superstones too and hopefully stop or help the warping issue since the warping seems to happen when the stones dry out. I emailed Naniwa and they gave the generic "its a splash n go stone" answer and directed me to email a US vendor for further help. I emailed the vendor and they gave me the same answer along with "stones shouldn't warp". I finally emailed Jon from JKI directly and asked him. That night before Jon could answer I decided to put my 5k in with the rest of my permasoakers, I got it for $40 I can live with it if it cracks.
I got a reply from Jon and he stated he has permasoaked the Naniwa Superstone line or at least has experience with it and has had positive results. He recommends once you start permasoaking them they should always stay that way, If you're going to dry them dry very very slowly.
My 5k has softened some and it definitely cuts quicker than before and seems to load a little less but more importantly it went in flat and it has stayed that way, no warping. I am going on a full week of permasoaking the 5k with no issues so far. To test my 8k and 12k I wet them down then wrapped them in a wet paper towel and put them in a plastic bag to keep the stones wet for 24 hours to see if they will get gummy / start getting super soft, they didnt. I ended up putting my 8k and 12k in with the rest of the permasoakers on Saturday this week. Yes there is a chance the stones can start to deteriorate and fall apart, Jon made that clear, but at this point they warp so bad they feel borderline useless anyways so Ill be the guinea pig.
I was going to share my experience with you all in a new post but I ended up stumbling on this thread out of nowhere and decided this would be a good place to share. Ill update you all as time goes on if you'd like but for now the permasoaking.
Sorry for the essay, I hope this helps someone out there.
Last edited:
Some Superstones warp, others do not. They're all made with the same binder though. So it sorta looks to be more of a manufacturing inconsistency thing. I had more SS hones that didn't warp, than those that did. If the binder was inherently problematic, then all of the SS I have owned would have warped. Talking several sets, many duplicates, etc.
I've cut one open after it was wet for about 45 minutes, it did not appear to be wet 'inside' past the first millimeter or so.
Naniwa often sells stones that are unbranded to wholesalers who then move them as "out of spec' stones - the reason they are 'off' is because of how they were baked; uneven heating, etc. I think the stones sold as off-spec are discolored. I have been wondering if some stones are affected but not discolored. Uneven consistency in the stone would explain why endless lapping won't bring the surface flat sometimes. At one point I literally lapped the 20mm 12k for 30 minutes straight and it was never flat, the surface seemed to be lapping unevenly. Softer spots lapping faster, and leaving the harder areas sitting higher.
My 12k warped on it's own without even getting wet. It was lapped flat, wet obviously, and then dried and checked many times over a month. Stayed flat. 3 months later, without being out of its case, it was warped again. I don't live in a tropical area. This has happened several times with long-ish periods of being flat, and dry and then still dry but not flat anymore. Right now - just checked it - the working side is not perfectly flat. It was flat about 2 months ago - and I haven't used it.
I had a 5k SS, 20mm, sit in a bath for about 90 min once, by mistake. It felt like it was dissolving. After it dried, it was not warped but it did not cut the same. Felt weird. Ironically, had the same thing happen with a Chosera 5k and the same sort of thing happened. Different binders but both felt compromised.
I think my next move is to cut the 12k down to a 5x2 piece, lap it and see what happens. I have had two other 20mm 12k Super Stones and they didn't warp. Just this one. One of the other two needed to have about 1/8" lapped off the top because it was sorta 'crusty' and the center was a bit discolored. Was fine afterwards.
I've cut one open after it was wet for about 45 minutes, it did not appear to be wet 'inside' past the first millimeter or so.
Naniwa often sells stones that are unbranded to wholesalers who then move them as "out of spec' stones - the reason they are 'off' is because of how they were baked; uneven heating, etc. I think the stones sold as off-spec are discolored. I have been wondering if some stones are affected but not discolored. Uneven consistency in the stone would explain why endless lapping won't bring the surface flat sometimes. At one point I literally lapped the 20mm 12k for 30 minutes straight and it was never flat, the surface seemed to be lapping unevenly. Softer spots lapping faster, and leaving the harder areas sitting higher.
My 12k warped on it's own without even getting wet. It was lapped flat, wet obviously, and then dried and checked many times over a month. Stayed flat. 3 months later, without being out of its case, it was warped again. I don't live in a tropical area. This has happened several times with long-ish periods of being flat, and dry and then still dry but not flat anymore. Right now - just checked it - the working side is not perfectly flat. It was flat about 2 months ago - and I haven't used it.
I had a 5k SS, 20mm, sit in a bath for about 90 min once, by mistake. It felt like it was dissolving. After it dried, it was not warped but it did not cut the same. Felt weird. Ironically, had the same thing happen with a Chosera 5k and the same sort of thing happened. Different binders but both felt compromised.
I think my next move is to cut the 12k down to a 5x2 piece, lap it and see what happens. I have had two other 20mm 12k Super Stones and they didn't warp. Just this one. One of the other two needed to have about 1/8" lapped off the top because it was sorta 'crusty' and the center was a bit discolored. Was fine afterwards.
I got a Naniwa SS 12k a few weeks ago and have used it maybe 5 times since then. Now it’s warped like a banana 
Is there anything I can do other than glueing it to a tile and lapping the crap out of it to get it flat again? Looks like I’d have to remove a few mm of material to flatten it.
Is there anything I can do other than glueing it to a tile and lapping the crap out of it to get it flat again? Looks like I’d have to remove a few mm of material to flatten it.
Wow! Yours look like the thicker 20mm sizeI got a Naniwa SS 12k a few weeks ago and have used it maybe 5 times since then. Now it’s warped like a banana
View attachment 1593962
View attachment 1593963
Is there anything I can do other than glueing it to a tile and lapping the crap out of it to get it flat again? Looks like I’d have to remove a few mm of material to flatten it.
I've heard the thicker Naniwa 12k 20mm will not warp and regretted getting the thinner 10mm that warped slightly now...
Looking at yours...wow!
Yes it’s the 20mm version. I specifically chose it because of warpage with the 10mm stones.
I’m going to contact the vendor and see what they’ll do about it. A little warping would be fine but this is nuts.
And I thought my 10mm 12k warped like crazy before I glued it to a ceramic tile! That is ridiculous.
~doug~
This level of warp is really crazy. Could it have been exposed it to heat/sun/radiator by accident or maybe soaked it in water?
As others have said I think they should be glued - or you should not give them your business anymore (my solution).
Looking closer at the picture, I'm wondering if the stone actually is warped or if its a poor lapping job?
It appears as if the warp is more pronounced on the lower face of the stone and the upper face actually seems to be quiet straight. But it might just be the camera angle fooling my eyes.
It appears as if the warp is more pronounced on the lower face of the stone and the upper face actually seems to be quiet straight. But it might just be the camera angle fooling my eyes.
It was never exposed to any heat while I had it. I’d lap it under running water then use it as a finisher before putting it away to dry in a cupboard. There’s no heat anywhere near it.
No soaking either, just lapping under running water and spritzing with water while honing.
Similar threads
