Which method should I use to lap new Naniwa 12k?

I should receive my new stone today. I will primarily use it for maintaining my straight razors.

I own a 6" x 2" DMT Course/x-coarse diasharp stone.

I believe the Naniwa is 8.25" x 2.75".

IMO I think my DMT should work well flattening the Naniwa since the Naniwa is just a little bigger.

The other options for me would be to buy wet/dry sandpaper. If I went this route, what grit should I use?

Which method should I use?

Been wondering the same thing myself. Gotta touch up one of my Harts and am wondering if my Norton flattening stone would be a good candidate to lap the Naniwa. EDIT: Was just gonna go for it, but since the exact question has come up, my hat is officially in the inquisiting ring.

I've heard nothing positive about the Norton lapping stone: mostly people call them aggressive and point out that they need flattening themselves as well. I lap my Shaptons and naturals with a DMT8C with good results and have used sandpaper before I got that. Since the Shaptons are very hard, they can handle coarse sandpaper well. The Naniwa Superstones are softer, so I would suggest the following:

- Draw pencil grid on stone
- Lap on sandpaper around 300-400 grit and see how this turns out.
- Too slow for your taste before the lines are gone? Step down to ~180 grit sandpaper and repeat. Finish around 300-400 grit, and if you're very anxious about a supersmooth stone, take it to 600-800.
Or use the DMT coarse (325 grit).

Many users lap under a running tap. I find that a wet DMT is good for lapping, but a running tap gives me too much water between the hones. I just splash it every few laps.

Just got done lapping with 320 wet/dry sandpaper. It took about 5 minutes.

About an hour ago, I tried to lap my stone with the DMT 6" but it is too small.

I then tried to lap with a used 220 wet/dry sandpaper screen (dry wall style). I used this screen on other stones on the past based upon a recommendation that they work better than regular sandpaper due to the holes in the screen. To be honest, it alway took about 20 minutes to lap my other stones using 220 grit.

I worked on the Naniwa 12k today for 20 minutes and 15% of the pencil lines still there. I then tried to push harder and the edge of the screen dug into the center of my stone leaving an indentation! Good thing the 320 wet/dry sandpaper I jsut bought only took 5 minutes to get the indented scratch out and all the pencil marks 3 times.

The DMT you want for lapping Naniwas and other similar sized hones is a DMT D8C 325 because it is big enough for the job. A brand new DMT can leave scratches in a Naniwa unless any high diamonds are knocked off first and that is from experience. There are a couple of threads about this and how to fix the DMT. I had to use W/D sand paper to get rid of the scratches left by the DMT. The DMT is fixed now and works well.

Bob

As Bob mentioned, the DMT D8C (325) is a good option. I use it to lap my kitchen sharpening stones and razor honing stones.

Before I got my DMT lapping stone last year, I read a lot of posts to decide which one to buy. I read a lot of bad user posts on the Norton lapping stone. As Laurens mentioned, many users had to lap the Norton lapping stone itself before using it. Others have indicated that the Norton lapping stone didn't last them long. I stuck with the DMT, have used it a lot for lapping and cleaning hones, and I'm very satisfied with it.

My experience with the Norton lapping stone has been good. I've used it to flatten my Washita, Soft Arkansas, Surgical black, Norton 220/1000, 4000/8000 and my 12,000 Naniwa. I can place a known flat straight razor on any of the stones, shine a light from the back and not see any light passing under the blade so I'm sure the stones are flat. The Norton lapping stone is not the fastest cutting, if memory serves, it took me over an hour to flatten my 220/1000. The Naniwa is definitely a softer stone and takes a lighter touch and a bit more finesse but still I had no problems. I've also put the lapping stone on the granite measuring table we have at work and check it and it's flat. So maybe I lucked out and got a flat one.

http://straightrazorpalace.com/srpwi...ne_Lapping_101

Good reading with pictures over there.