# DMT DiaSharp Coarse/Fine on SG2/R2



## bennyprofane (Jun 11, 2016)

For sharpening I use a DMT DiaSharp Coarse/Fine and then Naniwa Pro 1000 and 5000. I remember reading somewhere that Diamond stones shouldn't be used for fine SG2/R2 blades like the Takamura because they could cause microchipping. Wondering if this is true as I read in some DMT DiaSharp reviews that the reviewer was using them specifically for this steel with great results.


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## Pensacola Tiger (Jun 11, 2016)

Unless you are repairing a chipped edge or resetting the bevel to a new angle, you really have no need of the DiaSharp as the 1K and 5K should be sufficient. 

As far as using diamond plates, there has been some speculation that the XXC and XC DMT plates can leave deep grooves that weaken the edge and could promote microchipping. I can't say one way or the other as I use an Atoma 400 if I need a grit that coarse, but I've not seen microchipping on any of my blades regardless of steel.

Rick


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## bennyprofane (Jun 11, 2016)

Well, I fear I have some microchipping near the tip on my Takamura after cutting through some apple seeds (inside of an apple). (Is that possible?) I have no idea where else the microchipping could have come from as I was very careful. It's not really visible with the eye but can be felt or seen with a loupe.

I am also thinking about changing the angle from 18 overall to 25 to have more edge stability.


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## Pensacola Tiger (Jun 11, 2016)

18 overall? Is that 9 per side? Then it's no wonder that you are getting chipping of the edge. 12 to 15 per side (24 to 30 inclusive) is usually considered to be optimal for most double-bevel Japanese knives.


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## daveb (Jun 11, 2016)

I'm not the one to ask about such things but it looks to me like a foil edge where the foil has come off. Ask me if I've seen it before.

I got some advice here to blunt the edge to where it has some substance then start the bevel/sharpening over again.

On DMT's I've used F/XF to remove chips and sharpen a couple Kyocera (ceramic) blades. Not the best solution but only one I had at the time. Diamonds did not chip out the blade, quite the opposite.


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## AaronE (Jun 11, 2016)

Is this a new knife? There was a thread on here a few months back about the OOTB edge on the takamuras being very chippy. Consensus seemed to be that the issue went away after one normal sharpening session.


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## bennyprofane (Jun 11, 2016)

Pensacola Tiger said:


> 18 overall? Is that 9 per side? Then it's no wonder that you are getting chipping of the edge. 12 to 15 per side (24 to 30 inclusive) is usually considered to be optimal for most double-bevel Japanese knives.



As far as I know the Takamura R2 comes with an 18 overall.




daveb said:


> I'm not the one to ask about such things but it looks to me like a foil edge where the foil has come off. Ask me if I've seen it before.



What does that mean? That something is wrong with the knife?




AaronE said:


> Is this a new knife? There was a thread on here a few months back about the OOTB edge on the takamuras being very chippy. Consensus seemed to be that the issue went away after one normal sharpening session.



Yup, had it since a week. That's why I'm thinking I should reprofile and wondering if I can use my DiaSharp as 9 per side is perhaps too fragile.


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## XooMG (Jun 12, 2016)

A 400 grit stone is more than enough to clean up the edge and get you a stronger bevel. I did it with an 800 grit stone.


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## bennyprofane (Jun 12, 2016)

So my DiaSharp Coarse should be okay or should I just use the Fine side?


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## XooMG (Jun 12, 2016)

bennyprofane said:


> So my DiaSharp Coarse should be okay or should I just use the Fine side?


With diamonds, I'd start with fine, and finish mostly with edge trailing strokes because I think the abrasive will beat up the edge a bit. Just try it...you are not going to make the knife explode.


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## masibu (Jun 13, 2016)

i use pretty low angles for sharpening gyutos but sg2 I would add a higher angled microbevel or two on the finishing stone with very slight pressure. You can try the 24-30 degrees inclusive suggested but it could still be chippy even then. Id even run it at 40 degrees inclusive which will also reduce the time spent touching up the very edge. Just make sure to thin behind the edge now and then to ensure your microbevel stays nice and small. You can do your 9 degrees (or whatever youve been doing) each side on your 1000 and finish at 20 degrees (or whatever) each side on the 5000. the naniwa pro is the new chosera isn't it? I wouldn't hesitate grinding small chips with that. 

Whilst technically you could use the diamonds they are pretty aggressive and with high pressures you run the risk of damaging the plates or creating a problematic burr. Creating a clean edge on them isn't impossible but I outright suck at being delicate and stones are a little more forgiving in that regard. I feel like the 'mud' from the stones could aid in burr reduction but I could be spinning ****. 

If you feel you absolutely must use the diamonds just ensure you increase the angle slightly as you progress from one stone to the next so that you're grinding into fresh steel and not just flipping the burr from side to side


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## bennyprofane (Jun 13, 2016)

Thanks! So which stone should I use for thinning. Do I have to buy a new one? Is there a good youtube video on thinning?


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## rick alen (Jun 14, 2016)

If you are doing board work then a microbevel of 30deg+ inclusive is essential.

As far as the dmt, the xxfine as I understands starts off at about 3K, and after much use still gets no better than 6K finishes, not the 8K they claim. I feel SG2 really needs better than 6K to show it's stuff. And you don't need diamond to sharpen SG2.


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## LifeByA1000Cuts (Jun 14, 2016)

Just learned a hard lesson: NEVER NEVER try diamond plates for levelling a blade face (on a project knife luckily...semi-hardened carbon steel on a found and modded blade that I assume is diff-tempered.) for polishing on a stone (whatever the exact steel and hardness is, an asian-grocer-special hard-bound stone gives a nice mirror finish on it... just the damn low spots need dealing with....). Couldn't have scratched it worse with an awl. Estimated cost of repair will be at least 20 sheets of #240 emery paper...


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## bennyprofane (Jun 14, 2016)

Thanks!

So what is a stone recommended for flattening? I read somewhere that the Shapton Glass 220 is a good flattening stone. So Shapton Glass 220 and the Chosera 1000 for smoothing out?


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## Pensacola Tiger (Jun 14, 2016)

Diamond plates are best for stone flattening, as they never need to be flattened. The Atoma 140 is considered to be the acme of diamond plates, but a less expensive DMT or the diamond stone that JKI carries will work just fine.


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## bennyprofane (Jun 14, 2016)

So my DMT Coarse/Fine will work or do I need a more coarse stone?


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## daveb (Jun 14, 2016)

Use the fine. Only if yr not getting results should you go to coarse.


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## Pensacola Tiger (Jun 14, 2016)

bennyprofane said:


> So my DMT Coarse/Fine will work or do I need a more coarse stone?



No, the coarse side of your DMT is really not coarse enough for efficient stone flattening. For stone flattening, you should use a DMT XXC:

https://www.amazon.com/dp/B000GLPCO2/?tag=skimlinks_replacement-20


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## bennyprofane (Jun 14, 2016)

Oh, I wasn't talking about stone flattening (sorry, English is not my native language, I got mixed up) but knife thinning. So for knife thinning the Sharpton Glass 220 and then 1000 for smoothing?


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## Pensacola Tiger (Jun 15, 2016)

bennyprofane said:


> Oh, I wasn't talking about stone flattening (sorry, English is not my native language, I got mixed up) but knife thinning. So for knife thinning the Sharpton Glass 220 and then 1000 for smoothing?



The Shapton Glass 220 will work, but it tends to wear quickly. If you get one for thinning, try to use the entire surface of the stone so it stays flat longer. There are better stones for thinning. I've found the King 300 from Tools from Japan (http://www.toolsfromjapan.com/store...oduct_info&cPath=335_405_408&products_id=1669) to be an excellent stone for thinning. It is totally splash and go, is a fast cutter with decent feel and stays flat longer than other coarse stones. It's also a fairly thick stone (34 mm) and will last a lot longer than the Shapton Glass 220.


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## bennyprofane (Jun 15, 2016)

Thank you so much! The advice I get here is really amazing, so easy to buy the wrong things and waste lots of money. So, back to flattening (of stones), you recommend the Atoma 140. This seems to be a great offer? http://www.toolsfromjapan.com/store...oduct_info&cPath=335_462_464&products_id=1197


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## Pensacola Tiger (Jun 15, 2016)

Amazon (US) has them for $74, but yes, it's a good price.


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## bennyprofane (Jun 15, 2016)

Thanks! But I think the one for 74 is the sheet (they call it blade) which can better be seen here: https://www.amazon.ca/dp/B0186JFP7E/?tag=skimlinks_replacement-20


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## Pensacola Tiger (Jun 15, 2016)

bennyprofane said:


> Thanks! But I think the one for 74 is the sheet (they call it blade) which can better be seen here: https://www.amazon.ca/dp/B0186JFP7E/?tag=skimlinks_replacement-20



You're correct. The base plus sheet is $82. https://www.amazon.com/dp/B00BN32EXY/?tag=skimlinks_replacement-20


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## bennyprofane (Jul 9, 2016)

Today the King Deluxe 300 from Japan arrived. Great seller, the stone was out at first and to make up for it he sent it per air mail free of charge.
Do I break in (is that what the initial flattening is called?) the stone with my Atoma 140 or is the stone too hard for the Atoma?


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## Mucho Bocho (Jul 9, 2016)

Benny, Stu sent me one too. I just went to town on it. I thinned my Carter Muteki. The stone has great feel, works quickly and leaves a nice even scratch pattern that was easy to buff out with. Shapton 500 before the 220/444 paper. It's truly splash and go too. I'm very pleased.


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## Pensacola Tiger (Jul 9, 2016)

bennyprofane said:


> Today the King Deluxe 300 from Japan arrived. Great seller, the stone was out at first and to make up for it he sent it per air mail free of charge.
> Do I break in (is that what the initial flattening is called?) the stone with my Atoma 140 or is the stone too hard for the Atoma?



My Atoma 140 worked just fine.


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## bennyprofane (Jul 9, 2016)

Thanks! Yeah, looking forward to using it. German customs also just let it through without charging anything...


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## bennyprofane (Jul 9, 2016)

I havent used my Atoma 140 so far (just got it). Is it ready to go on the stone or is it too coarse initially?


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## Pensacola Tiger (Jul 9, 2016)

bennyprofane said:


> I havent used my Atoma 140 so far (just got it). Is it ready to go on the stone or is it too coarse initially?



It's fine out of the box. No "break in" needed.


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## daveb (Jul 9, 2016)

... . . .. .. ...... . ..... ................. .....


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## natto (Jul 10, 2016)

bennyprofane said:


> Well, I fear I have some microchipping near the tip on my Takamura after cutting through some apple seeds (inside of an apple). (Is that possible?) I have no idea where else the microchipping could have come from as I was very careful. It's not really visible with the eye but can be felt or seen with a loupe.
> 
> I am also thinking about changing the angle from 18 overall to 25 to have more edge stability.



18 deg sounds very shallow, that can be verified. Moving the knife edge leading over a plain board, lifting the spine until the edge bites gives an idea. My initial sharpening is following the given angles.

At high magnification the grey line at the left could be a small micro bevel. This could be a good pic of the usual wear, indicating lesser micro chips, gone after next sharpening.

If I am wrong please tell me what I see on this pic.


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## Obsidiank (Jul 10, 2016)

How do you store the knife? The micro chipping could be the result of a cheap knife block.


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## bennyprofane (Jul 10, 2016)

A wooden knife block but the blade doesnt touch the block.


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