Thread: Lapping new Naniwa 12K stone

I apologize in advance for the newbie question. I just acquired a Naniwa lapping stone and a 12K super stone. I saw what looks like instructions for using the lapping stone on the box that showed something from a small bottle (does not look like water) being poured onto the stone to be lapped. As all is written in Japanese, I have no idea what this might be. In the videos, all that is used for lapping on a water stone is water. Is something else required for the 12K super stone, or should I just proceed with water?

Thanks for you reply.

Use water.

As unit mentioned, you only need to use water.

That picture you saw is explained here. The substance poured onto the stone is silicon carbide powder, which helps speed up the lapping process. Naniwa lapping stones are made of silicon carbide, so the powder helps, but is optional.

Interesting.

I lapped mine with an old DMT 320 and tap water. It took about 5 minutes and I only needed to remove a tiny bit. It came much flatter than the Nortons I have seen.

In truth, I probably removed more than really necessary in effort to get one corner that dipped slightly (perhaps 0.25 mm?)...I could have simply marked it and just avoided that corner.

When I lap stones I place them in a sink and let water run over the stone and whatever I am lapping with, usually a DMT. I also use the running water with a glass plate and sand paper. The running water keeps things lubricated and clean. Just my way.

Originally Posted by unit

Interesting.

I lapped mine with an old DMT 320 and tap water. It took about 5 minutes and I only needed to remove a tiny bit. It came much flatter than the Nortons I have seen.

In truth, I probably removed more than really necessary in effort to get one corner that dipped slightly (perhaps 0.25 mm?)...I could have simply marked it and just avoided that corner.

By contrast, mine was severely high in the centre and took quite quite a bit longer than 5 minutes IIRC. I also had a corner that dipped, but I left it. It wasn't worth lapping off another 1/32" off the entire hone just to flatten a useless corner spot that is less than the size of half a dime.

Thanks to everyone for their replies. Now I am off to give it a go.

On topic question. So I have a new Naniwa 12k and a D8C. When I used the D8C to lap the Naniwa, either running under water or in a bin with water, the D8C just sticks to the Naniwa and makes it really tough to lap (and pull apart). This doesn't happen when I lap any of my Norton stones. Any advice on how to lap the Naniwa?

Originally Posted by Ryan82

By contrast, mine was severely high in the centre and took quite quite a bit longer than 5 minutes IIRC. I also had a corner that dipped, but I left it. It wasn't worth lapping off another 1/32" off the entire hone just to flatten a useless corner spot that is less than the size of half a dime.

Ryan,
I had the same issue with my Naniwa's, and others. All high in the center, and as you say, severely. After completing my Shapton set I tried the Shapton DGLP, very precise for flatness. When I used it, all of the hones I had lapped with the DMT 8C 325 previously were now all high on the ends. Turns out it was the DMT that was high in the center. Got a new one and it's the same, but not quite as bad. You might want to check your DMT for flatness. It didn't seem to affect the edges of the razors I honed on them, but it sure played heck with lapping.

Regards,
Howard.

Originally Posted by sixsixty

On topic question. So I have a new Naniwa 12k and a D8C. When I used the D8C to lap the Naniwa, either running under water or in a bin with water, the D8C just sticks to the Naniwa and makes it really tough to lap (and pull apart). This doesn't happen when I lap any of my Norton stones. Any advice on how to lap the Naniwa?

sixsixty,

The higher grit hones, and especially the Naniwa's are more dense, and smooth. This causes the DMT to suction down when it seals itself with slurry. Slide it to the side to get it loose, or slide slightly to the side and add water to the surface and then slide it back onto the water and it will loosen some. Figure 8's and keep fresh water on it. Good Luck!!

Regards,
Howard