Oil Stones differ from water stones in that they require the use of honing oil to float the swarf (metal particles). Also, these stones are commonly made from one of three different materials consisting of Novaculite, Aluminum Oxide (Corundum), or Silicon Carbide (Carborundum) and they all use oil to lubricate the stone and suspend the swarf in order to prevent the stone from becoming clogged. Also, while Novaculite and Coticule are the most traditional types of oil stones, there are also synthetic oil stones made by the Norton abrasives company called “India Oil Stones”.
When you apply a sharp knife to the surface of a tomato, cucumber, carrot or other food item it should - if you are holding it firmly and applying minimal pressure - sink into the particular item without effort. As such all you really need to work on is your technique and making sure you keep your fingers out of the way. With a dull knife however things aren’t quite so simple. When you apply a dull blade to, say, a tomato it’s not going to slice into the skin. Instead the skin will be able to push back meaning you’ll need to apply ever more pressure to get the knife to penetrate. Increasing the pressure on the knife increases the likelihood of the knife slipping off the offending food item to one side or another. And if it slips to the side where your hand is attempting to hold the vegetable steady you could be in store for a very nasty cut. Because even a dull knife will cause injury if there’s enough force behind it.
Steeling helps maintain sharpness. This process realigns the edge, correcting for dulling causes such as a rolled edge. A sharpening steel is a type of hardened cylindrical rod used similarly to honing stones. For example, a butcher steel is a round file with the teeth running the long way, while a packer steel (used in the meat packer's industry) is a smooth, polished steel rod designed for straightening the turned edge of a knife, and is also useful for burnishing a newly finished edge. Because steels have a small diameter they exert high local pressure, and therefore affect the knife metal when used with very little force. They are intended for mild steel knives that are steeled several times a day, but are not well suited for today's tougher and harder blade steels. Diamond steels are now available that have an industrial diamond coating and can remove blade metal as well as straighten, therefore used correctly they can re-profile a knife instead of just honing.