Shapton sharpening stones – how to get the best out of your Ha-no-kuromaku stones
Shapton's sharpening stones come in a stable plastic box designed to be used both as a base to hold the stone when in use, and to store the stone. The box has a low lip on its top and four rubber feet to keep the stone from moving around during sharpening (see photo, right). Every grit size has a different colour.
120-, 1000- and 2000-grit stones with and without their boxes. Click to zoom.
This text is a translation of the manufacturer’s directions for using the 12000-grit Shapton sharpening stone. The stones of other grit grades are similar enough in practical use for these suggestions to be applied to any other Shapton stone.
The soft plastic lining in the box is there to protect the stone during transport to the customer’s workshop and should be discarded after removal. The 12000-grit sharpening stone is cream colored and should be placed in water about 6 to 10 minutes before use, so that it has enough time to soak up the water that lubricates the stone while sharpening. It should not be left too long in the water, however, as this will tend to soften the surfaces of the stone too much. Never store the stone in water! After use, it should be left to dry, and then stored in the plastic box provided.
Honing with the 12000-grit stone goes quickly when the edge has been properly prepared using a series of progressively finer stones. You would normally start with the 1000-grit stone (orange), and then work your way through the 2000 (green) and 5000 (burgundy) stones. You will finish by giving the blade a final honing with the 12000-grit (cream) stone.
It is a good idea to sharpen as little as possible on each individual stone: this will reduce the degree to which a hollow is worn in the surface and so increase the sharpness of the edge that it is possible to obtain. This is only possible if you have enough different stones to work with. If you have too few, then you will need to work longer on each stone, and the stones will become dished more quickly.
To obtain the finest possible edge it is also important to get rid of the slurry of water and grit produced in sharpening. Clean your tools, your hands, the work surface and even under your fingernails. This will reduce the risk of transfering larger grits from one stone to the surface of the next finer stone.
The sharpening stone must be absolutely flat to produce an optimal edge. To flatten a hollowed stone, take a second stone (it should be finer than 1000 grit) and rub the two faces together. Both stones should first be soaked in water for 6 to10 minutes, and the surfaces of the stones wiped off so that moist areas cannot cause the stones to cling to each another and hinder the process. A second option is to use a truing stone. Always be sure to wash the stones thoroughly with water after flattening to remove all loose grit.
Frequently asked questions
Question: After honing a knife with the 12000-grit cream stone, I found big scratches on the blade.
Answer: If you have neglected to thoroughly clean your hands, the work surface or the knife before you change to the honing stone after sharpening with the coarser stones (orange, blue, green), larger grains will cross contaminate the surface of the fine stone and leave scratches on what should be a mirror surface after honing.
Question: I flattened the 12000-grit cream stone, but it doesn't cut as well as before.
Answer: The stone is too rough. Try resurfacing the stone with a finer abrasive (a finer sharpening stone, some silicon carbide powder on a truing stone) to make it smoother.
Question: I used a truing stone and silicon carbide powder to resurface my 12000-grit cream stone, but the surface is still too rough and doesn't have the hard, almost mirror smoothness it should.
Answer: The basic problem is that the stone was left too long in the water bath and the surface is now too soft. Take the truing stone and use a coarser grade of silicon carbide powder to grind down through the softened layer of stone to reach the underlying harder stone. Then refinish the stone with the fine silicon carbide powder to get the optimal surface.
Question: I use the plastic box to hold the stone during sharpening. The stone moves around on the box, making it hard to sharpen properly.
Answer: Insert a sheet of paper between the stone and the plastic box.
Question: I use the plastic storage box to hold the stone while sharpening. Even with the rubber feet, the box moves around and hinders sharpening.
Answer: The rubber feet do not hold well on some materials. Insert some paper or a rag between the box and the work surface.
Question: I flattened the 12000-grit cream sharpening stone with a truing stone and fine silicon carbide powder, but the surface doesn't look as good as it did when I bought it.
Answer: Before flattening, soak the stone in water for 6 to 10 minutes. If that doesn't solve the problem, use a bit more silicon carbide powder.
Question: My 12000-grit cream stone has unfortunately become too soft.
Answer: Softening or other changes in the substance of the stone mean that it was left in the water for longer than 30 minutes or was somehow exposed to a detergent. Also if you use a wooden support for the stone, and that becomes wet in use, the stone can soak up moisture from the wood, keeping it wet longer than advisable. If the stone is too soft, you need to grind down to a firm surface. Sand off the soft layer with a coarse sharpening powder, rinse and clean the stone thoroughly with water; then use a finer silicon carbide powder to finish the surface. Afterwards, allow the stone to dry and store the stone in its plastic box.
Question: Which side of the 12000-grit cream sharpening stone should I use?
Answer: Use the side without the writing first.
Question: My 12000-grit cream sharpening stone has developed small cracks.
Answer: Small cracks can develop if the stone is not used often enough, or if it is not used properly. Sand the stone until the cracks are no longer visible. Small cracks are not very deep. Resurface the stone as soon as possible once you notice cracks developing. The smoother the surface of the whetstone, the less likely it will crack.