[taketwoaspirin]

Hi All,

I've just notice that my new (ish) chinese 12k waterstone isn't completely flat. It's not far off, only just detectable when i laid it on a piece of glass, but i'm still obsessive enough to want it perfect!

Question is: what the hell do I use to flatten it? i used wet/dry sandpaper on glass for my norton, but it seems that the chinese 12k would be a lot harder. Or am I wrong?

Has anyone flattened one of these before?

Cheers,
Ian.

[Chris L]

Originally Posted by taketwoaspirin

Hi All,

I've just notice that my new (ish) chinese 12k waterstone isn't completely flat. It's not far off, only just detectable when i laid it on a piece of glass, but i'm still obsessive enough to want it perfect!

Question is: what the hell do I use to flatten it? i used wet/dry sandpaper on glass for my norton, but it seems that the chinese 12k would be a lot harder. Or am I wrong?

Has anyone flattened one of these before?

Cheers,
Ian.

Hi Ian:

Many of us have lapped a Chinese 12K. Some of these stones as their owners have described the lapping process, seem to be harder or softer. I have a very hard Chinese 12K that took quite some time on a diamond plate (DMT D8C at the time) to lap. Normally on natural stones like Belgian Combos, Belgian Blue, Barber Hones, etc I lap both sides. I stopped after lapping one surface of my 12K because it took such effort and I must be lazy.

Have at it with your wet/dry sandpaper on glass and use lots of water. Draw your pencil grid and sooner or later, the grid will be gone. Then if you're really determined, draw another grid and lap until the second one is gone. Then, happy razor edge polishing!

Chris L

[taketwoaspirin]

That makes sense chris, I'll give it a go. To be honest, it's probably so close to flat that it wouldn't matter (I've done 4 or 5 razors on it and they went ok). Still, I'm pretty obsessive, and i don't think my sickness will let me leave it alone!!

ian.

[Whiskers]

I had to lap mine twice.

Some 1k sand paper, something pretty flat to work on and some elbow grease and... voila ...

The second round of flattening is when I learned just how hard these stones are.


Dont forget to knock off the corners and edges. It does make a difference.

[Gothamitic]

I posted this method a while ago for some insight, and I got mixed replies, but this is how I flatten my 12K:

I draw a grid and rub it off with a Norton Flattening Stone. Then I draw another grid and rub it off with 600 grit sandpaper wrapped around a piece of 12" x 5" x 0.25" glass. Rinse and repeat with a freshly drawn grid and a 1000 grit piece of sandpaper.

My 12K is seems really hard to me, compared to my norton, and I've found that this progressive method really makes my 12K feel slick and with three grids to rub off, by the time your finished you may find that you're having trouble peeling the stone from the glass!

I'm also obsessive about flatness!

Good Luck!

[Utopian]

I am always amazed when someone describes lapping their 12K with a Norton lapping stone. Mine was way too hard for that and it just trashed my Norton stone without having any effect on the 12K. I guess that's just part of the mystique of using natural stones, like Forrest Gump's chocolates, you never know what you're going to get!

[randydance062449]

The DMT XXC (125 grit) would probably be the best to do a majority of the work or you can start with a coarse piece of wet/dry sandpaper.
In both cases, once the grid lines are gone from the coarse grit you should then move to a 500-600 grit for 20-30 laps and then to a 1000 grit for 20-30 laps as a finisher. You might even go to 2000 grit. It depends on the texture that you want.

I normally use a 1000 grit finish on my Norton 4/8 but that seems a bit coarse for the Coticule, Escher and Chinese 12K. For those I will be using a 2000 grit as a finish grit.

As already mentioned, be sure to round the edges and corners after every lapping of your hones.

Wrist supports for carpal tunnel syndrome are available at your local drug store!

[Bruce]

As I kvetched elsewhere about the phenomenon, the 12Ks are a... son-of-a-gun (expletives deleted for the sensitive of ear) to flatten. I wore out my first coarse DMT trying to lap the 12K. I leaned on the stone too hard while lapping and pulled the diamonds out of the matrix on one end of the plate.

So take it easy, use lots of water, and little more than the weight of the stone on the lapping plate. If you are going to use sandpaper, plan on buying more candles for the cake and invest in Abrasives Unlimited.

[CBMC]

It took me about 45 minutes to an hour to flatten the 12k (8x2 version, both sides) with the DMT 8C. I also noticed that the DMT was creating some fine scratches on one spot, I took a screwdriver to it to try to break it in, the scratches were still there. I am not too worried about the scratches they don't seem to effect performance. It really was a pain in the ass, especially after the ease of flattening a norton.

[vgod]

lapped my 12k on 800 grit wet/dry. did both sides and an edge. using the edge for smiling blades. such a difference in the feel of the hone. good luck.

and yeah, the carpul tunnel wrist guards are almost a requirement!!

vgod

[Swink]

I purchased mine very recently from Woodcraft and it lapped quickly on the coarse dmt plate. I was suspicious so I drew the lines again, but they disappeared in a couple of minutes. I was just lucky, I guess.

[jwoods]

very lucky you are, i remember lapping mine it took quite a while and a lot of wet paper as well but once they are flat i think they stay that way for some time

[blueprinciple]

400 grit wet and dry then 800 grit wet and dry on a piece of plate glass and keep going until the colour is an even grey. Pencil it up if you like but I found the colour change was a perfectly good indicator. Just be prepared to perspire a bit!

[Ben325e]

Here's a question: since typically harder stones have a finer girt rating (naniwa 10k not included), could it be that those who have these chinese 12k's that are pains to sharpen actually have a finer stone than those who have the softer ones?

I got one today and lapped it on various grits sandpaper on a granite reference slab that is dead flat, and it went pretty quickly for me. The finish is still great, but I can't help but wonder if the finish on the harder 12k's are better....

The blurb on woodcraft.com says the following:

Natural Polishing Water Stone

A dense, hard stone that's perfect for final polishing on all your carving tools, plane blades, chisels or any tool requiring a keen edge.

Extremely fine (12,000+) grit natural water stone quarried in the Guangxi province of China.

Because these natural polishing stones are cut by hand, dimensions may vary slightly.

Maybe the softer ones are 12000 or so, and the harder ones go even higher. This would explain why some use a coticule before the 12k, and some use one after the 12k. I'm sure that the grading of the coticule isn't that specific either, so that's also a factor....

Just a thought.


Ben

[Chris L]

Originally Posted by randydance062449

The DMT XXC (125 grit) would probably be the best to do a majority of the work or you can start with a coarse piece of wet/dry sandpaper.

I just got the DMT D8XX two days ago. If you're looking for a lapping plate that's equivalent to an industrial angle grinder without the noise, get this stone. Sakes alive does that lap aggressively! I've got one of the extremely hard 12k stones; you know, the kind that removed the diamonds from Bruce's D8C as if they were arm hairs yielding to a shave ready edge? It took me approx 45 min to lap one side of the 12K when I got it last year.

Enter D8XX..................I lapped the unlapped bottom side of the 12K as an experiment and was literally done with only the weight of the stone in less than 5 minutes. Keep in mind, as Randy said, the pattern it leaves is too coarse as is, and must be finish lapped on a finer lapping plate. Barber hones also wet themselves when they see this D8XX coming.

Originally Posted by Ben325e

Here's a question: since typically harder stones have a finer girt rating (naniwa 10k not included), could it be that those who have these chinese 12k's that are pains to sharpen actually have a finer stone than those who have the softer ones?

I got one today and lapped it on various grits sandpaper on a granite reference slab that is dead flat, and it went pretty quickly for me. The finish is still great, but I can't help but wonder if the finish on the harder 12k's are better....

The blurb on woodcraft.com says the following:

Natural Polishing Water Stone

A dense, hard stone that's perfect for final polishing on all your carving tools, plane blades, chisels or any tool requiring a keen edge.

Extremely fine (12,000+) grit natural water stone quarried in the Guangxi province of China.

Because these natural polishing stones are cut by hand, dimensions may vary slightly.

Maybe the softer ones are 12000 or so, and the harder ones go even higher. This would explain why some use a coticule before the 12k, and some use one after the 12k. I'm sure that the grading of the coticule isn't that specific either, so that's also a factor....

Just a thought.


Ben

Interesting question. If someone had a confirmed "hard" 12k and also had a "soft" 12k, experimentation could be done.

Chris L

[Utopian]

I completely agree with you on the D8XX. It makes the lapping of hard hones like the 12K and barber hones almost a joy!

[jwoods]

i had thought about the 120 grit to do my fine and medium spydercos but thught they might tear the diamonds out of it, but that is the hone of choice for naturals, even if you need to progress through 320, 600, 1200 that would be the easiest way to do it, i see what others meant when they said they put in 70 hours to lap a set of spydes, i have a lot of hours into mine maybe 20 and im halfway done thankfully i bought my ultrafine lapped here

[Swink]

Originally Posted by Ben325e

Here's a question: since typically harder stones have a finer girt rating (naniwa 10k not included), could it be that those who have these chinese 12k's that are pains to sharpen actually have a finer stone than those who have the softer ones?

I got one today and lapped it on various grits sandpaper on a granite reference slab that is dead flat, and it went pretty quickly for me. The finish is still great, but I can't help but wonder if the finish on the harder 12k's are better....

The blurb on woodcraft.com says the following:

Natural Polishing Water Stone

A dense, hard stone that's perfect for final polishing on all your carving tools, plane blades, chisels or any tool requiring a keen edge.

Extremely fine (12,000+) grit natural water stone quarried in the Guangxi province of China.

Because these natural polishing stones are cut by hand, dimensions may vary slightly.

Maybe the softer ones are 12000 or so, and the harder ones go even higher. This would explain why some use a coticule before the 12k, and some use one after the 12k. I'm sure that the grading of the coticule isn't that specific either, so that's also a factor....

Just a thought.


Ben

You just got yours recently, as did I. Maybe the recently mined ones are softer. Or, as it sounds like you got yours at Woodcraft too, maybe they got a soft batch.

[Ben325e]

Originally Posted by Swink

You just got yours recently, as did I. Maybe the recently mined ones are softer. Or, as it sounds like you got yours at Woodcraft too, maybe they got a soft batch.

I guess I need to clarify how I lapped mine - like you already read I lapped it on a granite reference plate with sandpaper, various grits. I pressed pretty dang hard on it too. I'd do about 20 or so strokes then I would rotate the stone 180 degrees and do it again, to help ensure that everything stayed even. There is a corner on my stone that isn't flat. I'd say that 90 percent of my stone is flat. I just didn't take it down to that level because 1) it's a long stone, and there is plenty of room for me to hone with; 2) I want my stone to last the rest of my life, so I just left the large flat area, and I'm sure it will get to be 100 percent flat during my lifetime, eventually.

So for all you guys who are flattening the entire stone, then hats off to you, but I'm more than satisfied with the current condition of my stone. I do think that if I were to try to flatten the entire face of the stone, that it would take a decent amount of time.

Ben

[Utopian]

Trust me the stone will last the rest of your life without any risk at all. With normal individual usage, your grandson might use it enough to get it to all the way flat. I don't think anyone has to worry about wearing out a natural hone, and certainly not this one!