lapping stones: grit or dmt

**binder** · 05-28-2012, 07:37 PM

I have a 4/8K Norton stone I want to flatten. I used sandpaper in the past and I think I embedded grit in it so with this one I thought I would try something else; also have a king 1200 stone. I thought I would try: 3" x 8" DiaSharp® Stone, 220x I can get this for $52.00 .The 325x is a lot more (I can pick up the 220x locally) so I would rather use the 220x if I can.

I also can get some lapping grit and use that and also purchase a DMT Dia-Sharp Credit Card Sharpener (coarse) for $37 with shipping.

I would like to hear experience on what would be a good choice.

Thanks

**UPD** · 05-28-2012, 07:39 PM

I use a DMT 325 for lapping, along with almost everyone else. The 220 will be fine, it will just leave a little rougher finish on your stone.

**hig789** · 05-28-2012, 07:52 PM

You can get a DMT8c 325 on amazon for $50 + shipping. I would use something after the 220 if you get it. that's pretty rough to leave a 4k or a 8k. Why do you need a credit card sharpener? Slurry? You can get them much cheaper than $37 if all it is going to be used for is slurrying.

**cb91710** · 05-28-2012, 07:56 PM

Yup.... DMT325, and don't even think of lapping with the DMT1200 unless you want to buy a new one. I was told that lapping will pop the diamonds right off... after I tried lapping my Naniwa 12k with it, and it doesn't seem to have the same coarseness along the entire length, I think I ruined it.

**jeness** · 05-30-2012, 01:41 AM

Buy a DMT 325, and be happy with it. 220 is too rough, 600 and 1200 too fine, and the credit card size stuff is simply too much of a hassle to use imo. If you don't like sandpaper, than go with a 325 DMT, or don't buy anything.

**Legion** · 05-30-2012, 02:36 AM

I used wet/dry sandpaper to lap mine initially, and then before each use (after soaking) I rubbed it under running water against my King 800 stone, which is about the same hardness. This seemed to keep both the King and the Norton flat. No fuss.

**cb91710** · 05-30-2012, 06:26 PM

Originally Posted by jeness

Buy a DMT 325, and be happy with it. 220 is too rough, 600 and 1200 too fine,

And I don't know about the 600, but I was told (after I had tried to use it) that attempting to lap with the DMT1200 will pop the diamonds off. It does seem to be VERY smooth in the center... for a 1200 I would expect some drag on the blade but I'm only getting drag near the ends.

**jeness** · 05-31-2012, 01:11 AM

Originally Posted by cb91710

And I don't know about the 600, but I was told (after I had tried to use it) that attempting to lap with the DMT1200 will pop the diamonds off. It does seem to be VERY smooth in the center... for a 1200 I would expect some drag on the blade but I'm only getting drag near the ends.

Test it with a glass bottle. If the middle of the stone scratches it, that there are still diamonds on it. DMT says that you shouldn't use anything finer than 325 for lapping, so I never did.

**honed** · 05-31-2012, 04:28 AM

Originally Posted by jeness

Test it with a glass bottle. If the middle of the stone scratches it, that there are still diamonds on it. DMT says that you shouldn't use anything finer than 325 for lapping, so I never did.

Actually on the latest DMT XXC I got there was a chart on the back of the box stating that only XXC & XC was recommended for lapping other stones.
However, I have used my 325 a lot for lapping, since, as stated here, you really want to smooth the surface a bit when you reach 5K or so, especially on razors.

**Krodor** · 05-31-2012, 07:50 AM

chuckle. I'm currently in the process of seeing if I can use my Norton 4k/8K to lap another rock...needing to lap the Norton often using a DMT325 of course. Hey, fun to experiment....

**cb91710** · 05-31-2012, 06:22 PM

Originally Posted by Krodor

chuckle. I'm currently in the process of seeing if I can use my Norton 4k/8K to lap another rock...needing to lap the Norton often using a DMT325 of course. Hey, fun to experiment....

Not sure you'll have much success with that.
I spent a LONG time trying to lap my Nortons with the Norton lapping stone... the DMT325 flattened them right out.
Same for the Naniwa... the Norton lapping stone didn't do the job but the DMT did.

**cb91710** · 05-31-2012, 06:23 PM

Originally Posted by jeness

Test it with a glass bottle. If the middle of the stone scratches it, that there are still diamonds on it. DMT says that you shouldn't use anything finer than 325 for lapping, so I never did.

There's SOME texture to the touch, so I'm sure if will scratch a bottle, but the feedback from a blade is very inconsistent across the surface, and I have some areas that look "bare" and other areas that have a black "waviness" to them.

**binder** · 06-06-2012, 12:56 AM

Originally Posted by legion

I used wet/dry sandpaper to lap mine initially, and then before each use (after soaking) I rubbed it under running water against my King 800 stone, which is about the same hardness. This seemed to keep both the King and the Norton flat. No fuss.

Did you use the King on the 4K? I tried a 1200 King Delux on the 4K and it turned it brown, and had to sand it out.

**Legion** · 06-06-2012, 01:59 AM

Originally Posted by binder

Did you use the King on the 4K? I tried a 1200 King Delux on the 4K and it turned it brown, and had to sand it out.

Never turned mine brown. You have to do it under running water of course.

Possibly the particles of my king 800 are too big to impregnate the surface of a 4k? Dunno, but I never had any problems. It just flattened and wiped off the dark swarf stains.