Naniwa Flattening Stone

[gaetanocarpinelli]

Hello everyone, I bought a 220 grit Naniwa flattening stone a few months ago and I've been using it a couple times on my Shapton Pro 1500 with fairly disappointing results... The Naniwa seems to be doing its job since I can see the slur created by the Shapton as it wears down but when I go and measure it to see if it got back to a nice flat profile I can still see that the stone is dished! Has anyone had this problem before? Or do you know what's the issue here?

 

[SeattleBen]

The short version is that you'll have better luck with a diamond plate which is more expensive. Longer version is that you'll be able to make that Naniwa work but you'll need to be at it more regularly and aggressively to make sure that your stone stays flat.

 

[M1k3]

The short version is that you'll have better luck with a diamond plate which is more expensive. Longer version is that you'll be able to make that Naniwa work but you'll need to be at it more regularly and aggressively to make sure that your stone stays flat.

...combined with Shapton being on the harder stone side of the equation.

 

[gaetanocarpinelli]

The short version is that you'll have better luck with a diamond plate which is more expensive. Longer version is that you'll be able to make that Naniwa work but you'll need to be at it more regularly and aggressively to make sure that your stone stays flat.

The hollow side it's not that deep to be honest and even by being aggressive I don't seem to get any improvement... It's odd

 

[DHunter86]

Is your flattening stone flat? These stones need to be kept flat as well, given that they wear with use.

 

[SeattleBen]

What we're getting at here is that you might be trying to flatten something that is harder than your flattening surface, which will just mean that you're shapton stone is flattening the flattener.

Think using a honing rod on a Japanese knife.

 

[ModRQC]

Correct your stone and your flattener using wet coarse sandpaper on a flat surface. Then use the flattener every single time, as much as needed, especially when thinning, using muddy dishing stones, and the likes. Keep the flattener flat with another course of sandpaper as often as needed - but it will behave better if what it flattens is kept as prime as possible, minimizing its own dishing. That's the cheap you don't need to spend anything more than some 5-10 bucks on quality sandpaper solution. I've had nice results with 3M cubitron in the 100 grits. The abrasives stay put, the backing is resistant and the sheet stays flat once wet, the stones got flat, admittedly involving a bit more efforts than with my Atoma 140. I could do about two Shapton coarser/medium stones on a single 9x11 sheet. Then it can be washed down and be used effectively still with say a much finer stone needing flattening.

 

[Benuser]

In addition only: the Naniwa will lose some particles, so you can't use the mud it raised. Rinse the flattened stone very carefully.
It's the most serious case of grit contamination you're likely to ever encounter.

 

[gaetanocarpinelli]

Do you think this will do the job? Won't it damage the stone in any ways?

 

[Yet-Another-Dave]

Do you think this will do the job? Won't it damage the stone in any ways?

I can't think why it wouldn't work. You would need a hard flat surface under it to keep it flat. Realize it will wear out and possibly clog fairly quickly, so you can't efficiently use a sheet too long before changing it.

For stone flattening I'd suggest Drywall Sanding Screen. E.g:

Since it's open it won't clog as easily and should go longer before you need to change it.

(But truth be told, a Diamond plate lasts longer and is so much more convenient that's what I really suggest.)

 

[M1k3]

I've also had good luck with 3M versus Shapton Pro 120

 

[DHunter86]

The 3M Cubitron II sandpaper is really good. Really like the polymer backing that's non-slip. Can definitely recommend.

I've also had luck using cheap Chinese made #120 and #80 grit diamond plates (about $6 per plate without backing here in Singapore) on the Shapton Pro 120. The #80 grit definitely brings back the factory surface (but I wouldn't use it on any other sharpening stone as it leaves deep gouges).

 

[Kawa]

For topicstarter:

I have the same Naniwa 220 flattener (I assume).
A common trick while flattening with this kind of flatteners is to put a pencil raster/matrix on your stone.
Keep on flattening until the pencil marks are gone everywhere, mostly the middle of the stone or the corners need a little extra time, depening on how you use your stones/ how your sharpen.
When all the marks are gone, your stone should be flat.

If you are already doing the pencil trick and you still feel your stone is not flat afterwards, then I also lean towards to your flattening stone might not be flat anymore....

Or do you apply uneven pressure while flattening? Since the flattener is smaller then most stones, you have to beware that you dont overflatten (make deep/low spots) some spots. For example then you go up-down-up-down, you actually hit the middle or your stone twice as much as the top and bottom side... you have to compensate for that (but this all would be noticable when you do the pencil trick anyway...)

 

[Staystrapped]

I soak the stone then put a sheet of 120 grit on my garage floor.

 

[Jovidah]

I've used those Naniwa sharpening stones - in varying grids - and frankly they suck. THere's also the problem that eventually your flattening stone can start to dish. The trick with drawing a grid helps to get results to at least get a flat sharpening stone, but using those flattening stones will always remain a pain.
Upgrading to an Atoma diamond plate made my life a lot easier.

 

[Kawa]

Ive used the 60 gritt aswell.
It is so coarse/hard, it doesnt grip any stone. Ive tried it on coarse 220 stones, aswell as 1000 gritt stones. Resulting in not flattening (only scratching) and never making a slurry (no goal, but for me it is prove and doesnt grind the whetstone)

The 220 Ive used with very pleased results for several years, even on harder choseras (400 and 600) and shapton pro (2000).
Only draw back for me is that it tends to make your stones slicker then original.

Got SiC powder for that once in a while, but for me thats a lot more mess/time.

I regularly flatten my 220 flattening stone with coarse SiC powder aswell.. Maybe it helps it staying flat.

 

[gaetanocarpinelli]

The problem here is that my flattening stone actually doesn't work. It is flat, it is brand new (as well as the Shapton pro 1500 I'm trying to flatten) but it just seems that it doesn't do the job it was made for. I've tried any possible method with no good results, so I came to the conclusion that it's a bad quality, cheap (18$) flattening stone.