Lapping stone newb question

I've seen the lapping wiki and could be perfectly happy with sandpaper and marble as I wouldn't be lapping all that often, *but*

given that I'm considering a Naniwa 12k, I see that SRD also has a Naniwa 220 grit lapping stone at over 1/2 the price of a DMT 325 that leads me to a couple questions:

1.) Can the Naniwa 220 be used to lap just about any stone?
2.) What are the grooves in a lapping stone for?
3.) Is there a reason I don't hear more about this lapping stone versus everybody being on about DMT 325 in every thread;) ?

Regards

I have never used one so I don't really know what its capabilities are but the grooves are for allowing the slurry that builds up to be flushed away easier. I would imagine that it would be okay to lap most stones save some really hard stones like translucent and hard black arkansas stones which I have found that glass and SiC work best. I think the reason why the naniwa lapping stone doesn't get too much attention when compared to the 325 is that the DMT's are the flattest lapping plates out there and they last forever and work really really really well. Also the Naniwa lapping stone is very similiar to the norton one in looks and the norton one doesn't have the greatest reputation so the similarity probably makes some think that it is the same stone just sold under different names (not saying that they are or aren't just saying they look the same).

I have the DMT 325 and two Atoma lapping stones. Oddly enough, I have found myself using sandpaper instead, going through 180 sometimes to speed things up, then 220 and 400. I have grits all the way to 2000 and above but usually stop at 400 even on my 20K grit finishing stone. It is just so easy to use sandpaper, and there are no negatives to using it. The lapping stones are fine, but sandpaper is now my chosen method.

Thanks for the feedback, ace. The sandpaper thing came from the wiki http://straightrazorpalace.com/srpwi...ne_Lapping_101