Resurfacing a Medium Norton India Stone

[John Crawford]

Hi Everyone:

I'm continuing wandering through the process of trying to learn to use oil stones.

I'm using a medium India as a coarse stone. It dished a bit, so I flattened it with a diamond stone. This turned out to be a mistake, as the stone is now much smoother than it should be..... So, I'm trying to rough it back up again.

80 grit sandpaper doesn't budge it. 60/90 s/c grit on a flat plate roughs it up a tiny bit.

Have any of you had experience with these?

Many thanks again for all the help....

[David Weaver]

You could try rougher grit, but once you grade the stones, it's hard to get them as fresh as new. Silicon carbide should do about as much as you're going to get out of it.

Use medium viscosity oil when you hone on it for a little while, as anything lighter may be allowing particles to stay between the pores in the stone.

[John Crawford]

David: Thanks as always for your help, it is really helpful and a time saver when experimenting with these things.

In general, is an India stone not designed to be flattened or re-flattened, or is this eventual loss of coarseness just something you plan on happening?

Is it typical for a medium India to dish? I probably have sharpened 10 vintage plane irons, and 5 chisels on it. Not a major dishing, but it began producing a nicely cambered iron, the kind you might strive for on a smoothing plane. I am not fastidiously using the whole stone for each sharpening, but on the other hand am not grinding a bunch of chisels staight down the middle of it....

Ok, thanks again....

[Jim Matthews]

Would a diamond plate and a little kerosene do?

Lamp oil is commonly available in hardware stores,
it's light enough to handle something like this.

I wonder if a fine masonry block would serve as a grinding medium?

[Steve Voigt]

I regularly resurface my fine and medium India stones with 60-80 loose SC grit on glass. No, it will not cut as fast as did out of the box, but it cuts plenty fast, and resurfacing keeps it flat. India stones are soft enough that you should make an effort to use the whole stone, otherwise it will dish, as you experienced.
I think if you use the stone for a while, you will get comfortable with the speed of cut.

[John Crawford]

India stones are soft enough that you should make an effort to use the whole stone, otherwise it will dish, as you experienced.

Thanks Steve, you guys are like the missing manual....