Thread: Curved Naniwa Combination Stone

I just noticed that my Naniwa Superstone 3k/8k combination hone is not entirely flat. Along the line between the 3k and the 8k side it i slightly bent, looking pretty much like the bimetal piece in old school thermostats. I do not know if this was the case when I got the stone, or if it recently changed.

Has anyone seen this before? Can temperature variations cause this? Or do the different grits respond differently to soaking in water?

Maybe I should split the stone in two pieces (with the advantage of having two sides of each grit size) before lapping it flat again. Would appreciate any input on this, did anyone try to split a combo?

Second, What do you use for cleaning Naniwa superstones from metal residue and other dirt that assemble on the surface? May the ordinary dishwasher detergent from the kitchen have a negative impact on the binding resin in the hone?

Sincerely,

Sedell

Hello and welcome to the forum. If you have soaked the combination stone in water that may be the cause of the warping. Naniwa Super Stones are not meant to be soaked in water just spray some water on the surface and hone. The two pieces are very thin and it is very easy to damage Naniwas so I don't think trying to get them apart would be a good idea. Possibly just let the hone air dry thoroughly for an extended time and see if that helps.

To clean the hone of swarf left on it from honing most use a DMT plate or wet/dry sand paper on a really flat surface. A search on lapping hones should bring up quite a few threads on the subject.

Bob

To clean the steel residue from your stones use a few drops of Dawn (blue) dishwashing detergent and a nylon dish sponge. The blue colored synthetic scotch brite sponges. Lightly rub the stone surface with the detergent and water. They clean up real nice. I've been doing this several times a day and have never seen any adverse effects. I use the super stones and choseras daily. Let your stones dry slowly and naturally away from any heat source.

I've never put soap to my synthetics. I will either lap them or, in between lapping, a nylon fingernail brush and cool clear water. Does the deed for me. I was under the impression that soap wasn't friendly to synthetics, and might damage the stone, but I could be (shudder) wrong.

Also it is best to lap the surface of the stone flat every so often. If you haven't been doing so, once you do you'll see an improvement in your results. A hassle but just part of the trip.

Hi all,

thanks a lot for the answers.

I don't soak the Naniwas, just keep them a few seconds under pouring water before use, and then the usual wetting while honing. But, when honing for quite some time, the stone is constantly wet, and I guess the water goes quite deep into the hone.

The thing I'm worrying about, is that the stone will keep changing its shape, which would mean a lot of lapping and fast tearing down of the hone. But, possibly the warping was already present when I got the stone, and hopefully it won't change much from now on. Last lapping didn't remove much material and gave good results.

I'm letting it dry thoroughly now, and will lap it flat tomorrow again. Found a 4/8 half-hollow Haan-Solingen on a flea market the other day, and I'm eager to get it sharp.

Also, thanks for the comments on cleaning the Naniwas, will keep rinsing with the scotch sponge, and try to minimize the use of detergent. It seems to me, that the detergent sucks in to the stone a bit, and gives a few bubbles when honing. Not sure if thats bad for the hone in the long run.

Cheers,

Sedell