Chinese 12K “break-in”

[Earcutter]

Bought myself a Chinese 12K – lapped it, then lapped it some more. I have run two blades over it after have honed them up to a Naniwa 10K; once after soaking it, the other merely whetting it. Unfortunately, both times it has seemingly done nothing but “dull” the edge.

I have heard that they sometimes they need a “break-in”period but I am not sure? Anyone have any insights for me.

It's odd as the rock feels so smooth and yet...

[hig789]

What grit did you lap it to? I took a BBW and and smoothed mine out after lapping.

[Earcutter]

What grit did you lap it to? I took a BBW and and smoothed mine out after lapping.

i might have gone overboard here. The last stone I took to it was an 8K... lol. She's flat!! And oh so smooth lol.

[Doc226]

I don't have one but from what I have read most C12K are slow and 100 laps may the lower end of what is needed

[rajagra]

i might have gone overboard here. The last stone I took to it was an 8K... lol. She's flat!! And oh so smooth lol.

Maybe it's too smooth. I may have made the same mistake with a similar stone (Dragon's Tongue.)
It's natural to think that smoother is better, but on reflection it's just going to be different. It may or may not be better with a coarser (but equally flat) finish.
I will definitely roughen mine up at some point to give it a fair tryout.

[Pkrankow]

Try lapping it lightly on some 800 grit and then seeing if it will do anything. It is possible to polish the stone till it will not cut.

Phil

[kelton]

try it with some slurry

[PapaFish]

I am pretty sure the "break in" would just be smoothing things out with the blade, and you have definitely gotten it smooth if you took it to 8K! I found that with mine, the edges it produced got finer and finer as the surface finish of the stone progressed up to about a 1200 grit. That's all the higher sandpaper I have, though it has received additional buffing with various stones since then. at 1200 grit, the surface wanted to hold water, now, it wants to repel water. My razors typically get 100 or 200 passes on the Chinese when finishing. I stop when the razor is easily passing HHT3 or better. It's a great stone :).

[Earcutter]

Thanks guys - I'll "rough it up" a little and get back to you all - lets hope that's what it is. BTW Doc, I gave them over 100 laps so that's not it.

[Wid]

Being a natural stone it might not be as fine a the Naniwa 10K. From what I have read, they do very somewhat.

[Luc]

Did you use a pencil to make a few lines on the hone before you lap it?

[Earcutter]

Did you use a pencil to make a few lines on the hone before you lap it?
Yeah I do - I'll do it again as I re-lapp it. Maybe I made a unknowing mistake.

[cb91710]

Try lapping it lightly on some 800 grit and then seeing if it will do anything. It is possible to polish the stone till it will not cut.

Phil
This.

DMT 325 is all I lap with. And as indicated above (and even in the eBay auction), yes, these stones take 100 laps or better.

My progression is to set the bevel on a DMT 1000, then the Norton 4k/8k, Naniwa 12k, followed by the CNat 12k (which IMHO is nowhere near the same as the Naniwa 12k.

[Earcutter]

Did you use a pencil to make a few lines on the hone before you lap it? Too much! Kind of shocked but it wasn't as flat as i thought!! Not sure how that happened but... Glad I did it again - good call.


This.

DMT 325 is all I lap with. And as indicated above (and even in the eBay auction), yes, these stones take 100 laps or better.

My progression is to set the bevel on a DMT 1000, then the Norton 4k/8k, Naniwa 12k, followed by the CNat 12k (which IMHO is nowhere near the same as the Naniwa 12k.
Well I just re-lapped it with my DMT! Nearly broke my heart to do it lol. To see all those "scratches." The other thing that hurts is when I lapped it as fine as I did, water didn't soak in worth a darn, now you can see the water soaking in as it sits.

Thanks for all the help thus far gents. Will let you know how the next hone goes on the rougher surface.

[bones59]

I hope I never need to lap one of those again :a52:

[Earcutter]

I hope I never need to lap one of those again :a52: Yeah I have heard that but mine is not problem to lap! Hope I don't have a dud lol.

[jeness]

I never found a C12k that was to my liking. I tried about 4 of them, they were all nice to use, but in the end all were outperformed by my Jnat, and even my 10k Naniwa, so I sold them all. Imo they are not worth to be messed with, only if you wan't to make it very cheap. There are much more reliable finishers out there, and you don't have to guess how good they are.

[cb91710]

I hope I never need to lap one of those again :a52:
I spent hours attempting to lap both my Norton (the 4k side lapped out but I never could get the 8k flat) and the Naniwa 12k using the Norton lapping stone.
When I switched to the DMT 325, it flattened all four stones (4k/8k/Naniwa/C-Nat) in less than 30 minutes.

[Debrushman]

In order to cut down on the number of passes required with a C12, start with circles and slight pressure. Followed by circles with no pressure, thana few X strokes, than finish with regular laps as needed. The circles take a great deal of time off the C12.

[professorchaos]

I hope I never need to lap one of those again :a52:

I hope I never need to use one again. A kick in the crotch to lap and excruciatingly slow to use. :a52: They make my hardest Asagi seem quick.

[Earcutter]

Second last Report:

Ok gents - I re-lapped the stone. My heart broke seeing scratches on the thing after polishing the thing like a king but... so be it. I figured try. I was kind of ready to give up but I didn't.

Tonight I honed up two blades and after running them on their final Naniwa polishing Naniwa stone - the 10k, I was kind of scared to ruin the edges with the Chinese 12K (again). I ran the first one about 150 laps not stopping - just going for it. The draw was allot heavier, but you know whatever.

Fantastic! Wow, the hair on my arm was not popping off - it was just disappearing. Gave the second blade a go - same thing.

I know the shaves are going to be awesome - I'll report back but wow, what a diference!!

Final report tomorrow. Thanks for all your help guys!!

[cb91710]

Good job man.
I know they are sold as 12k, but really... mine feels finer than my Naniwa, and delivers a MUCH keener edge. I suppose it's possible that it is still a 12k, but the relative hardness results in less rounding of the bevel?

[paco664]

if you really really wanna see something try some oil... or better yet diamond slurry in oil.....

the c12k LOVES oil and diamonds...

[cb91710]

What kind of oil? Olive? Grapeseed? Mobil-1?

[Earcutter]

For what it's worth Rich - Pacco and Doc got me to try oil on my Coti and I didn't like it too much. Very, very keen. But I loved it on my barbers hone. let me know what you think of it on your 12K. I used olive.

[cb91710]

I'm just thinking that oil would be more manageable than water... especially here in Chino where the boiling point of water is either just below room temperature, or the de-humidification effect of the AC results in things drying within seconds.

[Earcutter]

LOL - that bad eh! Maybe? - http://www.sharpeningsupplies.com/Lansky-P168C57.aspx?gclid=CJiuwPLH968CFeZgTAodT35iGg

242793Edit - on second thought it's a petroleum product and that might change the dynamics of the stone. They say to use petroleum on hones if it's cutting too fast as it closes the "pores" and slows things down - hence, this might not be the thing.

[PapaFish]

I use mineral oil. It doesn't smell, and it's safe to drink (it's a laxative). Baby oil is scented mineral oil work additives like vitamin A. Norton honing oil is a highly refined mineral oil. Many honing oils smell awful, at least in my opinion.

[Earcutter]

Well it wasn't a bad shave at all! Using a new to me blade is not a good way to test the 12K though, as I noted the W&B 100 yr old steel felt very different indeed! It shaves kind of like my Kami - hard to explain.

I can say difinitively though that the 12K worked!! It was a nice shave. Shouldn't be long before I get it working like a champ. It'll be fun to test it on one of my regular rotation.

[PapaFish]

How fine did you lap it the second time? If you prep both sides, you can have two different finishes. Take one to 1200 grit or so, polish the other side up good. See if following the 1200 grit side with the polished side has any affect. I am guessing that it was working, just too slowly to see results (just a guess).

[Krodor]

Holy criminy, seriously? I figure a 325 grit DMT would be enough, then it sounds like 800 wet/dry is enough. You've taken yours to 1200 grit and went even farther on the other side? Wow. I'm still figuring mine out, but I stopped at not-quite-done-with-800-lapping, and got a nice edge at 150 passes or so (not that I tried before then). But wow, to consider 1200-grit lapped not polished...yowzah, you are either a honing-saint or have some real patience I'd cant dream of. That polished side must be slllllooooowwwww ;) bet its a good edge tho!

It's fun to hear what others do so I can try it too, but I think once I get mine 800-grit lapping done, I'm calling it quits and being happy with whatever I get ;)

[PapaFish]

Ha! I like it! I'm not a "honing saint", but I like the phrase. The reason I took my one side to 1200 grit was because Harbor Freight had an assortment of wet/dry sandpaper for $4, and 1200 is where it ended :). There was a notable difference in edge production between a 100 grit, 220 grit, 500 grit, and 1200 grit finish. Only one side of mine is prepped at the moment, it's been up to 1200 grit, then polished with my Spyderco Ultra Fine (or should I say, then it polished my Spyderco Ultra Fine?). It is slow, but I like the edge off it a lot, so I don't mind. I keep working on the other side every time I lap another stone, but don't hold your breath (those saw marks are deep, and the stone is slow to lap). What I describe above is what I have in mind for mine long term.