# Just ordered a Sukenari HAP 40…do I need new stones?



## Rainmaker (Aug 25, 2021)

Used to work in a professional kitchen years ago (Montrachet and Per Se in NY when it just opened) but no longer. I managed to collect quite a number of knives in the process. 



I just purchased a Sukenari HAP40 Gyuto (and a Sukenari HAP 40 “slicer” on back order) as my daily but looking through my kit I’m not sure if my stones are up sharpening the HAP 40s efficiently. I have 1000 and 6000 grit stones purchased from Korin and a DMT fine/extra fine somewhere. 



I’m thinking of adding either a Takeshi Saji AS Nakiri or a JCK Novel R2 Bunta for veg prep. My other knives are a mix of a few Masamoto CT series and a few Suisin Inox, a Misono UX-10 gyuto plus MAC bread knife and paring knives if that makes a difference. 



For those with experience with HAP 40, what stones do you use and which ones do you recommend (brand and grit)? 



From my research, it seems I should be looking at shapton glass and pros, suehiro cerax, and nubatama platinums. There were also a few suggestions of going diamond stones/DMTs. But there doesn’t seem to be a clear choice.

Many thanks.


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## SirCutAlot (Aug 25, 2021)

I use Shapton Pro for HAP 40, they work well... I usualy stop at 8k, but only use a sujihiki for meat/fish protein slicing. For veggie tasks i prefer a 3-5k edge. 

SirCutAlot.


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## HumbleHomeCook (Aug 25, 2021)

I don't have HAP40 so please take this with the requisite amount of salt...

HAP40 does have a reputation for being one of the more challenging steels for average sharpeners but it doesn't cross the widely accepted (and admittedly general) threshold of exceeding 4% vanadium to require diamonds to get the most out of it. Most everyone I've seen use standard water stones. Like so many of these very hard steels (ZDP-189, etc.) the challenge comes mainly from the hardness itself and not the carbides like you see in high-vanadium steels (S90V, etc.).


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## adam92 (Aug 25, 2021)

Rainmaker said:


> Used to work in a professional kitchen years ago (Montrachet and Per Se in NY when it just opened) but no longer. I managed to collect quite a number of knives in the process.
> 
> 
> 
> ...





Rainmaker said:


> Used to work in a professional kitchen years ago (Montrachet and Per Se in NY when it just opened) but no longer. I managed to collect quite a number of knives in the process.
> 
> 
> 
> ...


Which jck bunka do you want to get? As I know only one is available, which is Fu-Rin-Ka-Zan White Steel No.1 Series FRKZW1-7 Bunka 180mm (7 inch), same as TF nashiji bunka. 

The heat treat is very nice, but many others here experience bad fit & Finish, some overgrind blade like the one I used to have. 


Nakiri only use for vegetables, while bunka is same as Santoku, which can use for meat & fish. If you only planning to get a knife for vegetables, mainly push cut, then go for nakiri, otherwise gyuto is better choice as the shape allow you to rock chopping the herbs, push cut or slicing motion.


Either cerax, shapton pro/glass, king hyper/Deluxe will cut the steel, only difference is the cutting speed & tactile feedback. 

If you prefer convenient, go for shapton pro/glass. 

For meat, I recommend stop at 1/2k grit, vegetables 3/4k, fish 6/8k. 

You'll need a rough stone to keep you others stone flat & thinning.


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## Rainmaker (Aug 25, 2021)

adam92 said:


> Which jck bunka do you want to get? As I know only one is available, which is Fu-Rin-Ka-Zan White Steel No.1 Series FRKZW1-7 Bunka 180mm (7 inch), same as TF nashiji bunka.



I was looking at the JCK Novel R2 Bunka. This one: JCK Original Kagayaki NOVEL Series | R-2 Laminated KN-2 Bunka 175mm (Kiritsuke, 6.8 inch) or this nakiri: Takeshi Saji Aogami Super Custom Series Nakiri 165mm (6.4 inch, Ironwood Handle). 

I just purchased a Gyuto: Sukenari HAP-40 Series Wa Gyuto (210mm to 270mm, 3 sizes, Octagonal Bocote Wood Handle with Water Buffalo Horn Ferrule)


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## Steampunk (Aug 25, 2021)

I'm not sure what Sukenari's HT of HAP-40 is like, but based upon my experience with the steel from other makers I'd consider it to be very cusp-y in terms of its ability to be sharpened on AlOx stones.

Removing material isn't so much the problem. It's shaping the carbides to form as keen of an apex as this steel can support that is... Comparing Shapton Glass, Suehiro Cerax, Naniwa Pro, JNS 800 (Which is an SiC stone), diamond plates/strops, Coticules, and J-Nats on HAP-40... All can remove material, but only the diamonds, and to a lesser extent the SiC, actually make it feel that sharp. Higher grit Shapton Glass/Naniwa Pro stones just seem to burnish it, and make it feel slippery. Coti's are surprisingly capable of grinding HAP-40, and forming a burr, but the deburred edges are really slippery and not too sharp feeling.

At or below 1K you might be able to get away with a Cerax, Naniwa Pro, or Shapton Glass, but higher grit AlOx stones seem just to make the steel feel slippery. Even at 1K, it's not as keen and biting as what it feels like it should be.

An 800-grit SiC stone like a JNS 800, or the King NEO 800 definitely gives HAP-40 a sharper and more toothy-feeling edge than a 600-1000 grit AlOx stone. This is also still a fairly low grit for kitchen work... However, it's not in the same league as diamonds on this steel in terms of bite and sharpness. Diamonds really seem to help to take this steel to the level of performance it can really show. Plates, resin bonded, vitrified, or strops... Diamonds really unlock something special with HAP-40.

Sharpened on diamonds, it retains one of the toothiest yet shaving sharp edges I've ever encountered, for the longest time. A hybrid edge, from a 1200 grit diamond plate jumping to 1-micron diamond on a hard balsa or basswood strop, is pretty magical. Huge bite, but shaves like a demon. It takes so much abuse without losing bite (If the HT isn't pushed to the roof, you can do some pretty shady things to this stuff.), it's astonishing, isn't too reactive, and really isn't a chore to sharpen compared to something like Aogami Super. Even thinning is sort of doable by hand providing it's clad... I'm just not sure you really see the best out of this stuff without diamonds. It also cannot be ground quite as thin behind the edge as some other steels without creating problems. So, you're a bit limited in how thin you can really take it for performance.

You kind of need to let it be your workhorse, catering for a big crowd under not ideal conditions, kind of knife.

So, TLDR... Yes, it can be abraded on 'normal' AlOx stones at low-medium grits, but the edges don't really get good until you do diamonds.

People say that 3% Vanadium is the max for AlOx stones, but I actually think it's more like 2% Vanadium (Like SG2.) if you actually expect a great edge from _some_ AlOx stones. You're still getting stone-sensitive at this sort of level.

Hope this helps.


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## Rainmaker (Aug 25, 2021)

Steampunk said:


> …
> 
> Sharpened on diamonds, it retains one of the toothiest yet shaving sharp edges I've ever encountered, for the longest time. A hybrid edge, from a 1200 grit diamond plate jumping to 1-micron diamond on a hard balsa or basswood strop, is pretty magical. Huge bite, but shaves like a demon. It takes so much abuse without losing bite (If the HT isn't pushed to the roof, you can do some pretty shady things to this stuff.), it's astonishing, isn't too reactive, and really isn't a chore to sharpen compared to something like Aogami Super. Even thinning is sort of doable by hand providing it's clad... I'm just not sure you really see the best out of this stuff without diamonds. It also cannot be ground quite as thin behind the edge as some other steels without creating problems. So, you're a bit limited in how thin you can really take it for performance.
> 
> ...



Thanks Steampunk for the comprehensive reply. 

The Sukenari HAP 40 is heat treated to HRc 68. 

As for diamond stones, will DMT do or is there a specific brand you recommend? How about CBN stones?


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## M1k3 (Aug 25, 2021)

Steampunk said:


> I'm not sure what Sukenari's HT of HAP-40 is like, but based upon my experience with the steel from other makers I'd consider it to be very cusp-y in terms of its ability to be sharpened on AlOx stones.
> 
> Removing material isn't so much the problem. It's shaping the carbides to form as keen of an apex as this steel can support that is... Comparing Shapton Glass, Suehiro Cerax, Naniwa Pro, JNS 800 (Which is an SiC stone), diamond plates/strops, Coticules, and J-Nats on HAP-40... All can remove material, but only the diamonds, and to a lesser extent the SiC, actually make it feel that sharp. Higher grit Shapton Glass/Naniwa Pro stones just seem to burnish it, and make it feel slippery. Coti's are surprisingly capable of grinding HAP-40, and forming a burr, but the deburred edges are really slippery and not too sharp feeling.
> 
> ...


Was going to say something like this. I'll add that, diamond stones even make a big improvement on the edges of cheaper, softer, stainless steels.


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## captaincaed (Aug 25, 2021)

I have a Ryusen HAP-40, and I've found it surprising easy to sharpen and deburr on standard fine stones. That said I haven't sharpened it much. I'm still waiting for the day it needs a full work up, and running into needing to shape the vanadium carbides. 

I think any more, it really pays to have at least one mid grit diamond stone in your tool kit. Plates are fine, if you only do things now and then. Diamond stones if you're doing it a lot. 

I also found diamond helped a lot with Ryusen R2, hardest steel to deburr I've found, but I think others find it easier. Maybe my Achilles heel.


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## Barmoley (Aug 25, 2021)

Both DMT and CBN stones will work. You can try spyderco CBN for an inexpensive version, it gets good reviews. These won’t feel nice, but will do the job. Finish on diamond loaded strop and you are good to go.


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## Steampunk (Aug 25, 2021)

Rainmaker said:


> Thanks Steampunk for the comprehensive reply.
> 
> The Sukenari HAP 40 is heat treated to HRc 68.
> 
> As for diamond stones, will DMT do or is there a specific brand you recommend? How about CBN stones?



68hrc is going to feel REALLY glassy to sharpen, on any media. AlOx at lower grits struggled at 63-65hrc with this steel; you probably need a harder abrasive.

You're going to enjoy the sharpening feel on a resin-bonded diamond like the JKI or Naniwa diamond stones, a lot more than on Diamond/CBN plates at this sort of hardness.

DMT's would work in combination with diamond stropping compounds, but their quality control has dropped significantly in recent years. Even at their best, they really needed to be broken in for awhile before you tried them on better quality tools. Right out of the box, they could really tear up the edges on thin/hard blades. Lately, Dianova, Ultra-Sharp, or Atoma diamond plates seem to be a little better quality. They tend to be a little coarser for their grit rating, but also (I'd say Atoma, Dianova, and Ultra-Sharp in order from best to 'okay'.) are much more durable and consistent. Just make sure it's broken in on a chisel, plane iron, some softer knives, a fine/soft natural stone (BBW, Lv.3 J-Nat, etc.), or a piece of mild steel bar, and then use little or no pressure when sharpening that 68hrc Sukenari. It won't feel awesome, but combined with some diamond or CBN stropping compounds, they will do the business.

Can't comment much on CBN, alas. The abrasive is hard enough, but these stones are still pretty rare compared to diamond.

On thin edges, a good 1200 will be a lot more useful than the coarser grit plates.

Frankly, at least a pair of resin bonded diamond stones (1K-ish, and 3-6K ish.) will be a much nicer sharpening experience for steels like this than my cheaper plate/stropping compound solution. I'm not sure you really need the really coarse diamonds until you start getting into those 4%+ Vanadium steels (AlOx can grind HAP-40 just fine.), but for refining HAP-40 at or past 1K, they really can help.

I agree with @captaincaed regarding the increasing value in resin/vitrified bond diamond stones today. SG2/R2 is really the tipping point for me, where I really start thinking these would be nice to have, and by today's standards this is a pretty lightweight PM steel. Even Aogami Super and 1.2562 at 65hrc+ can sometimes start feeling like diamond is a good idea, if you just want to touch-up rather than create a hybrid edge... If you really want to keep playing with some of the modern 'super steels' on the market, AlOx water stones are starting to get outdated. If you stick with older-tech steels, the older tech stones will never go out of style, and keep being amazing.

Hope this helps.


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## Steampunk (Aug 25, 2021)

M1k3 said:


> Was going to say something like this. I'll add that, diamond stones even make a big improvement on the edges of cheaper, softer, stainless steels.



I would concur. My favorite edges on cheap & nasty stainless tends to be from diamond plates. They're not as easy to create as on something like the JNS 800 (Which is easier to deburr on than plates.), but are even keener for their grit, and have awesome bite.


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## captaincaed (Aug 25, 2021)

Always great to hear you chime in @Steampunk, wealth of knowledge.


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## MrHiggins (Aug 25, 2021)

My first Japanese knife was a Sukenari Hap40 gyuto. I had absolutely no problem keeping it sharp with my Gesshin stones (1000, 4000, 6000). I loved that knife and miss it to this day.

I think the opinion that Hap40 is hard to sharpen is way overblown. That said, I never did anything extensive in terms of sharpening/thinning, just touchups to keep it sharp. 

I think you'll enjoy your new knives!


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## adam92 (Aug 25, 2021)

Rainmaker said:


> I was looking at the JCK Novel R2 Bunka. This one: JCK Original Kagayaki NOVEL Series | R-2 Laminated KN-2 Bunka 175mm (Kiritsuke, 6.8 inch) or this nakiri: Takeshi Saji Aogami Super Custom Series Nakiri 165mm (6.4 inch, Ironwood Handle).
> 
> I just purchased a Gyuto: Sukenari HAP-40 Series Wa Gyuto (210mm to 270mm, 3 sizes, Octagonal Bocote Wood Handle with Water Buffalo Horn Ferrule)


If You're looking for only vegetables knife, nakiri is a great choice. Good for push cut but not so much for slicing & rocking. 

I used to have nakiri only for vegetables, I love it wheb prep heeps of vegetables.


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## Rainmaker (Aug 25, 2021)

Steampunk said:


> 68hrc is going to feel REALLY glassy to sharpen, on any media. AlOx at lower grits struggled at 63-65hrc with this steel; you probably need a harder abrasive.
> 
> You're going to enjoy the sharpening feel on a resin-bonded diamond like the JKI or Naniwa diamond stones, a lot more than on Diamond/CBN plates at this sort of hardness.
> 
> ...



Thank you Steampunk for taking the time to share your experience and recommendations. Sure helps a lot.

Never knew resin bonded diamond stones existed.. I found Naniwa stones on Amazon and the JKI stones at, well, JKI. Prices are close that they’re a wash but the JKIs include nagura stones so I’m leaning towards that.

I‘ve never had stones lower than 1000 grit as I haven‘t needed them. Have always kept the factory angle. I’ll be ok with just the 1000 and 6000, right? (especially if I‘m on top of maintenance and never let them get too dull?). Speaking of which, for periodic touch ups on the diamond stones, do I need to go 1,000 —> 6,000 or will 6,000 do?

Should I need to buy lower grit stones, will the suehiro cerax #320/#800 suffice? Any thoughts on the nubatama platinum stones? 

Geez, this side project got really expensive really fast. I also replaced my boards with Asahs and Hasegawas! Hahaha!


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## M1k3 (Aug 25, 2021)

Rainmaker said:


> Thank you Steampunk for taking the time to share your experience and recommendations. Sure helps a lot.
> 
> Never knew resin bonded diamond stones existed.. I found Naniwa stones on Amazon and the JKI stones at, well, JKI. Prices are close that they’re a wash but the JKIs include nagura stones so I’m leaning towards that.
> 
> ...


Venev also makes resin bonded diamond stones.


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## Rainmaker (Aug 25, 2021)

M1k3 said:


> Venev also makes resin bonded diamond stones.


 
Yeah I saw those on the Gritomatic website. And they come two sided too! So basically half the price of the others.

How do they compare to the JKIs and Naniwa though? And which grits would you suggest? The Dragons are out of stock on the finer grits. Only the Phoenix are available. So 240/400 and 800/1200 and be done with it?


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## memorael (Aug 26, 2021)

Just go with any stone that abrades the steel, If you do want to go all in abrade the carbides with a diamond stone or silicone oxides or alum oxides. It will take time, coticules wont do anything to the carbides and probably wont abrade the metal either or will do so very slowly. My suggestion is go with the lowest diamond micron stone you can and then refine with something like choseras.


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## Justinv (Aug 26, 2021)

I’ve used shapton glass 4000 then gone to 1u diamond loaded balsa strop. This seems to work well for maintenance.


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## Steampunk (Aug 26, 2021)

Rainmaker said:


> Thank you Steampunk for taking the time to share your experience and recommendations. Sure helps a lot.
> 
> Never knew resin bonded diamond stones existed.. I found Naniwa stones on Amazon and the JKI stones at, well, JKI. Prices are close that they’re a wash but the JKIs include nagura stones so I’m leaning towards that.
> 
> ...



Lower grit grinding on AlOx like the Shapton 220 or Cerax 320 should be fine, in case you need to do more major repairs or thinning. Otherwise, from 1K up, the JKI or similar stones should be fine. If Sukenari has done their job well, you should need coarser stones until you need to thin, or if you experiencing major chipping (HAP-40 @ 68hrc is not going to be as robust as at 64hrc.). 

Providing you are not letting the edge degrade too far, the 6K diamond should be fine for touch-ups. I've found HAP-40 to dull very linearly, and touch up easily. 

I can sympathize with feeling you got in deeper than initially expected with a knife purchase... I've done exactly the same. Fortunately, once you're set up for this one, you'll be prepared for the custom in K390 you purchase in a couple years... Until you get into thinning and polishing. Then, that's a whole new kettle of fish. 

Hope this helps. 

P.S. Alas, I cannot help you with the Nubatamas, other than to say that chasing AlOx stones for steels like this is a lost battle.


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## M1k3 (Aug 26, 2021)

Rainmaker said:


> Yeah I saw those on the Gritomatic website. And they come two sided too! So basically half the price of the others.
> 
> How do they compare to the JKIs and Naniwa though? And which grits would you suggest? The Dragons are out of stock on the finer grits. Only the Phoenix are available. So 240/400 and 800/1200 and be done with it?


I haven't used the other ones. So I can't give a good comparison. I'm a big fan of the Phoenix 400/800 I got. I have no complaints and want to get higher and lower grit ones. The edges straight off the stone are really nice. Stropping almost feels pointless.

The 800 works out to 2Kish japanese grit rating. I'd suggest those stones you picked out.


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## memorael (Aug 26, 2021)

Justinv said:


> I’ve used shapton glass 4000 then gone to 1u diamond loaded balsa strop. This seems to work well for maintenance.


Most people will tell you "you" need some crazy progression. Use what works for you and keep going man. DMT XXC, DMT XC, DMTC then some 1k and a jump to 6k works. Is it the prettiest? no, but damn me if it doesn't cut through boxes of onions and tomatoes.


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## memorael (Aug 26, 2021)

Steampunk said:


> Lower grit grinding on AlOx like the Shapton 220 or Cerax 320 should be fine, in case you need to do more major repairs or thinning. Otherwise, from 1K up, the JKI or similar stones should be fine. If Sukenari has done their job well, you should need coarser stones until you need to thin, or if you experiencing major chipping (HAP-40 @ 68hrc is not going to be as robust as at 64hrc.).
> 
> Providing you are not letting the edge degrade too far, the 6K diamond should be fine for touch-ups. I've found HAP-40 to dull very linearly, and touch up easily.
> 
> ...


If your going to thin on cladded knives any sand stone will do. Nubatamas when they first appeared were rebranded stones and I have no clue if they work or not. If you stick to Choseras, Shaptons and any reputable stone it will abrade the knife, there is no quick way other than good technique and an understanding of how abrasives work. As far as I am concerned no steel is harder than common abrasives, carbides in the hardest form aren't a high percentage of the knife edge and rarely get in the way of a good edge. If you want the absolute best just work a very long time on good stones.


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## Rainmaker (Aug 26, 2021)

Steampunk said:


> Fortunately, once you're set up for this one, you'll be prepared for the custom in K390 you purchase in a couple years...



Oh no you don’t! I’m not even going to google that…that sounds like the entrance to a very expensive rabbit hole! Hahaha!

But seriously, many many thanks!


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## Rainmaker (Aug 26, 2021)

I ended up purchasing the Venev 240/400 and 800/1200. I figured I could use the 1200 grit for maintenance. Should that not suffice, I’ll get the JKI or Naniwa 6000.

The 240/400 on the other hand I figure I can use to learn on. I was thinking of a side project of re-bevelling some of my older knives and giving each a symmetric double bevel… for ease of maintenance and *hopefully* a more robust edge. I just need to figure out the optimal angle for the different steels such as the carbon steel of the Masamoto CT, the Swedish steel of the Misono UX-10, the Mac knives, etc., all of which have 60/40 to 70/30 bevels. I suspect the proper angle would be somewhere around 12 dps or 24° inclusive. I’ll probably get a feel for the new stones by sharpening my old Wusthofs that are just lying around unused then start in earnest with a Mac paring knife first and see if I can really come up with the courage. The concept and buying the stone is one thing. Putting the steel to the stone is quite another…. That just might save me from buying new knives in the meantime….hmmm probably not. Haha

Thanks every for your invaluable input….


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## kayman67 (Aug 26, 2021)

That 1200=~5000 grit. I'd start at 400 (that's actually ~1100 or around that) and do some passes on 800 (~3000 JIS) and 1200 (~5000 JIS). 
240 (~325 JIS) hard bond, would be to reshape the bevel, take out chips and so on. 
These should give you some screaming sharp edges.


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## jwthaparc (Aug 26, 2021)

Rainmaker said:


> Used to work in a professional kitchen years ago (Montrachet and Per Se in NY when it just opened) but no longer. I managed to collect quite a number of knives in the process.
> 
> 
> 
> ...


You need to throw everything away right now! Buy a shapton sharpening pond! Nanohone flattening plates! Suehiro Debado low grit stones! gouken high grit stones! Hurry! Super vitrified diamond stones! DO IT! Hurry! You dont have time to think about it!














Jk. Nah you'll be fine with what you have.


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## Rainmaker (Aug 27, 2021)

Do I need to match the grit of the nagura stone with the grit of the diamond stone if all I need the nagura for is to clean the stone during sharpening when the diamond stone gets loaded? I just ordered Venev 240/400 and 800/1200 stones.

Alternatively, would the rust erasers work In place of the naguras? I already have a few of those.


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## kayman67 (Aug 27, 2021)

I've put this to a test and still find that rust erasers are a crappy way to clean any stone while using them, Venev included. I didn't see it as clearly as when using multiple options in parallel. As a side note, for some reason, the rust eraser tends to "glaze" the surface of 800/1200 Venev. Not sure why. 
Using the nagura from Chosera (that 600 grit one), had so much better results in terms of cleaning and surface speed after, but the nagura itself is very aggressive. I'd say one or two passes are more than enough. Another 1000 grit nagura was a milder option, taking out less material.


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## Rainmaker (Aug 27, 2021)

Thanks. So a 1000 grit nagura will work on the 240/400/800/1200 Venevs when used exclusively as a cleaner while sharpening?


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## kayman67 (Aug 27, 2021)

Yes. Use it only when needed, especially with the OCB sides.


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## Rainmaker (Aug 27, 2021)

Would this work too?









Naniwa Nagura Dressing Stone


Clean Water Stones The Naniwa Nagura Dressing Stone is an optional stone used for cleaning and refreshing the surface of Naniwa and other water stones. During sharpening, swarf, the waste metal removed from the blade being sharpened, can build up on the stone's surface.



www.sharpeningsupplies.com


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## kayman67 (Aug 27, 2021)

Yes, but use it gently over a couple of passes. It will overpower the OCB by a good margin. Also seems like it delivers the most aggressive surface after.


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## Rainmaker (Aug 27, 2021)

Many thanks.


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## M1k3 (Aug 27, 2021)

Rainmaker said:


> Do I need to match the grit of the nagura stone with the grit of the diamond stone if all I need the nagura for is to clean the stone during sharpening when the diamond stone gets loaded? I just ordered Venev 240/400 and 800/1200 stones.
> 
> Alternatively, would the rust erasers work In place of the naguras? I already have a few of those.


I was using my SG 4k, now using my King 6k since I haven't been using it for anything else, for this role.


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## Rainmaker (Aug 28, 2021)

So this arrived today….










































And got one of these too just to try it out….


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## kayman67 (Aug 28, 2021)

That little Glestain is a star for me. 
Gyuto looks great.


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## inferno (Aug 30, 2021)

Rainmaker said:


> For those with experience with HAP 40, what stones do you use and which ones do you recommend (brand and grit)?



imo the shapton pro and glass works fine with s30v, r2 and srs15. and these are very similar.


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