Stones have long been the preferred method for sharpening knives and tools. The wide array of natural stones available throughout the world have various features that give them many advantages over those of manufactured stones. We highlighted the best manual knife sharpeners that take advantage of these characteristics. Let’s take a look at some of these differences and see why it is that many sharpening professionals still prefer natural stones their man-made brethren.
Types of Stones
There are four main types of sharpening stones. Some occur naturally and others are manufactured They include oil stones, water stones, ceramic, and diamond. Oil stones and water stones were originally found by mining. Now they are often manufactured.
One of the most popular choices for knife sharpening is the oil stone. Natural oil stones are often referred to as Arkansas stones since this is where the vast majority of them are mined. Manufactured stones are made of materials that range from silicon-carbide to aluminum oxide. (Some knife sharpening systems such as the Apex from Edge Pro utilize oil stones. These types of systems are much easier to learn than standard stones.)
Oil is used as the lubricant with these types of stones because it allows for the most effective friction between the stones surface and the metal of the blade. When you sharpen any type of knife or tool you are essentially removing small amounts of metal from the blade itself. The oil that is used in conjunction with a stone keeps these pieces of metal from embedding themselves in the surface of the stone thus making it less effective.
The embedding of metal particles is often called clogging and it is not unique to oil stones. By using oil and keeping the particles in a ‘solution’ it keeps the stone from clogging and makes it much more effective at sharpening.
As the name would suggest water stones use water as a lubricant instead of oil. The stones are typically submerged for 15 minutes or so prior to use. The water creates a slurry on the surface of the stone that keeps metal fragments from clogging the sharpening surface. Water stones are highly effective at creating a very polished edge. For this reason they have long been the preferred stone of Japanese sword and knife makers.
One downside to water stones is that they tend to wear more quickly than other stones. This is because of the softer material with which they are made. For this reason it is important to utilize the entire stone for the sharpening process. This keeps one section of the stone from wearing down faster than the others making it difficult to hold a consistent angle.
Ceramic stones have become very popular in recent years. If properly cared for they can last a lifetime. They are also available in a range of grits that can handle anything from repairing to polishing a blade.
The materials with which they are made ensure that the sharpening surface will remain flat indefinitely. They also don’t require the use of lubricant. This is handy when you’re not in a place where oil or water is convenient.
Diamond stones are not really stones at all. They are metal plates onto which a diamond abrasive is bonded. Although they tend to be more expensive, they do have several important advantages. They require no lubrication. They are extremely durable. A quality diamond stone should last a lifetime. On top of all that they also cut very quickly and are one of the few stones capable of sharpening carbide blades on tools and knives.
So What Do Pro’s Prefer?
While it might seem that all of the advantages are stacked in favor of manufactured stones such as ceramic or diamond, many professional sharpeners still prefer natural and synthetic stones.
This is in large part because they offer much more in the way of feedback when sharpening a blade. Take the example of a diamond sharpening stone. The diamond abrasive material is not designed to break away from the metal plate on which it is embedded. Therefore only material from the blade itself it is removed. While this often means sharpening takes less time, it is also more difficult to get a polished edge as the diamond abrasive causes more friction. Diamond abrasives are popular in many electric models like the Wüsthof.
This isn’t the case with softer natural stones. While it may seem like a hassle to have to deal with messy lubricants, oil and water stones offer a very precise level of feedback. The abrasives from the stone break away in a predictable manner giving the sharpener a clear indication of progress throughout the process. This allows sharpeners to work both quickly and efficiently when sharpening their blades. And the variety of grits available between the two types of stones provide a sharpener with everything they need to repair and polish a blade.
Stone-Based Knife Sharpening Systems
Because they allow such specific control of the type of abrasive, speed, pressure and direction sharpening stone systems are very popular with professional sharpeners. The Wicked Edge (read more here), and the Edge Pro from Apex (read more here) are two of our favorite models.