Oil stones are known for their durability, and many are actually passed down from father to son. Eventually, even the well-maintained oil sharpening stone will become dished, usually in the middle, from the effects of repeated sharpening over many years. Once this happens, the stone will no longer be able to sharpen properly and you will have to level, or flatten, it to bring it back to usability.
Spray the back of the 220 grit sandpaper and stick it with the grit side up on a flat surface.
Apply honing oil to the top of the oil stone.
Flatten the stone by rubbing the face of the sharpening stone on the sandpaper in a circular or figure eight motion, stopping periodically to check the face for flatness. Stop rubbing it once the face is flat.
Repeat the process using progressively finer grades of sandpaper, if needed, to remove scratches left by the previous grit.
Things You Will Need
- Spray adhesive
- Wet/dry sandpaper: 220, 400, 800 grits
- Honing oil
- Flattening is best done on a granite surface, but a piece of medium-density fiberboard (mdf) or slab of metal will work as well.
- Most home improvement stores don't carry sandpaper of grits finer than 400. You can find grits up to 2,000 at automotive supply stores.
- Make sure that your sandpaper is not finer than the oil sharpening stone. Coarse stones may not need more than 220 grit, while the finest oil stones rarely exceed 800 grit, with 1,200 being the finest grit typically available.
- Failure to use wet/dry sandpaper with the honing oil can result in the sandpaper peeling away during the flattening; this can result in uneven wear on the sharpening stone.
- Using grits of sandpaper finer than the sharpening stone can burnish the face of the stone, reducing its ability to sharpen.
- The honing oil lubricates the sandpaper grit and the stone and carries away debris from the flattening process. Not using it can damage the face of the sharpening stone and require more flattening to repair it.