Thread: Some thoughts on lapping waterstones

Olivia turned me on to the Dieter Schmid's Fine Tools site some time ago and it is where I bought my Naniwa superstones. I paid more but the 20mm thick no base feature appealed to me. This site has a section on using Japanese waterstones here and they recommend soaking the stones for 6 to 10 minutes before lapping. JimR, who lives in Japan, was kind enough to call Naniwa at my request to find out if they recommended soaking the stones and they said it was optional IIRC.

What I started doing is spraying the hone liberally with water and walking away for five minutes. I come back and draw a pencil grid and lap under running water. I have found that letting the water sit on there for five minutes seems to cut my lapping time down considerably. I'm assuming it is softening the binder but I'm not sure.

I lap my synthetics before every honing session regardless of which brand of stone. I always use a pencil grid and so far so good. I find the grid is the best way to really know what is going on with my lapping. For one thing it proves to me that even if I only hone one razor and come back to the hones a week later they do change and need to be lapped if they are going to be absolutely flat.

I am going to take one of them and check it with a micrometer and make a note of the thickness before I lap and after. I will do this for awhile and see how much I am losing. My impression is that it is not very much per session.

Great post Jimmy! I'm very interested to hear your results!

I tend to only lap my stones once some swarf has built up on the surface and they could use a clean! But I'm interested to know how much material is lost in each lapping session. Hopefully not too much, and my stones will last a while! Hehe!

A question for you Jimmy. Have you ever tried to trick the pencil grid?

I mean, erase the grid by grinding irregularly?

Usually there is some steel residue left from previous sharpening. I use that and the way the stone feels to tell me when its flat.

I am not criticizing what you do-except for 2 hand freehand under the faucet, but consider this: if your goal is to simply erase the grid your mind/hand may just do that without regard for flat.

my thought on lapping is to learn the feel with one part fixed and stationary.

Originally Posted by kevint

A question for you Jimmy. Have you ever tried to trick the pencil grid?

I mean, erase the grid by grinding irregularly?

Usually there is some steel residue left from previous sharpening. I use that and the way the stone feels to tell me when its flat.

I am not criticizing what you do-except for 2 hand freehand under the faucet, but consider this: if your goal is to simply erase the grid your mind/hand may just do that without regard for flat.

my thought on lapping is to learn the feel with one part fixed and stationary.

No I lap in the kitchen sink. I have the GDLP sitting on a DMT in a holder to raise it up a bit. I do the grid lightly so that I don't have to lap more than necessary and I focus on being even and turn the stone end to end frequently. I use the x routine as described on the Shapton USA website.

I read early on that Harrelson lapped by the color of the hone being even and the feel I suppose. I have lapped a grid and drew another and lapped that to double check but I am confident that I'm getting the hone flat with the method I'm using.

During the honing with the Naniwas or with the Shapton pros I also hit the plate to remove swarf if it is building up enough for me to feel it necessary. If it weren't for the binder causing slight warping or whatever it is doing I guess it wouldn't be necessary to lap before honing. Nature of the beast though.

Hi again Jimmy. See i knew you HAd it down.

I only wanted to remember the emphasis is not to remove the grid. The techniques you describe are most helpful to create an even, flat surface. A new self teaching chap might easily gain the habit of removing the grid which need not be the same as creating a plane.