Humankind has been using whetstones for millions of years. They have been used to sharpen tools, knives, arrowheads, anything that utilizes a cutting edge. Today there are several to choose from ranging from those with fine grit to whetstones that have a very coarse grit. The grades are different and are based upon key criteria; the material they are made up of, the type of abrasive surface they have, simplicity of use, the availability of the stone, and the cost. Common types include oil stones, diamond embedded, water, and natural stones. Each have certain characteristics that differentiate their uses.
Oil stones can be found in nature but they are usually man-made of aluminum oxide. They are fairly cheap to produce and therefore inexpensive to purchase. The drawback with these stones is the mess made from using oil. The oil is needed to remove metal filings during the sharpening process. These filings are known as swarf. They must be removed or the abrasive surface of any whetstone is adversely affected.
Diamond stones are made of tiny diamonds which are embedded or glued onto a metal surface. They are the hardest of the whetstones and the best at producing a fine edge. They can be used to repair the surfaces on softer whetstones. They are also the most expensive but they do last a long time with the proper care.
Water stones can be synthetic or natural. Like all whetstones they have differing grit levels related to the abrasive texture on the surface. They use water instead of oil to remove the swarf and can produce a better edge than oil stones. They are inexpensive but wear out faster because they are the softest of the whetstones. If they lose their shape they are sometimes flattened by another stone with a harder surface, usually the diamond whetstone.
Another type is known as natural stone. These are made up of silica. The interesting thing about this stone is that it can be used dry or wet with differing abrasive surfaces or grit. Except for diamond stones the natural whetstone is the quickest at sharpening edges especially when water or oil is used.
Long ago when man started using tools with sharp edges his choices of whetstones were limited to any rough surface he could find. After all these years, through trial and error, and research and developement we have much more refined choices to make. There are different grades of whetstones out there for just about every purpose. Whether the need is for a rugged long-lasting stone like diamond, or for occasional use by a weekend camper, there is a whetstone out there that will help put a sharp edge on edged tools. After all didn’t man find out long ago that an edged tool works best when it is sharp?