The Origins of Shaving
Most historians agree that the history of shaving began when human culture began; which would be to say, ancient history. Prior to the invention of steel, ancient people had the use of shells, that could be utilized for tweezers, and volcano glass, which is incidentally among the sharpest materials available. Furthermore, they had pumice stones and also other rocks they were able to use to remove undesired facial hair. Other materials include sharpened shark's teeth, clam shells, and flint. Some tribes still use flint to shave with today. Skip forward to the Bronze Age and Roman times and archaeologists have unearthed examples of very early straight razors These early examples did not have much in common aside from a sharp edge, and they were produced from bronze.
These early razors were sharpened by either sharpening the shells or teeth on other rocks, or in the case of flint and obsidian, through flint knapping. The first bronze and iron razors were sharpened very much the same as modern knives, albeit without the advantage of special guide rods, diamond stones, and the luxuries we take advantage of today. In those days, ancient peoples needed to get by with what they were able to find; which would be to say, the finest "rock" they could find.
The Rise of Steel
Fast forward some more, and our ancestors discovered iron ore. When iron was discovered, so was steel.. Adding carbon to iron, making it red hot, then cooling it quickly hardens the steel; enabling blacksmiths to craft what we know today as steel.
From the invention of steel came newer, sharper, and more durable tools. These new tools included new knives and all manner of sharpened instruments, some peaceful, some made for war. At this point in history, the razor didn't evolve much further from the sharpest tool the local smith could fashion. Such a precise instrument was probably available only to the rich. These early razors were really at most special knives. Of course, straight razors are essentially a specialized knife. Ancient razor sharpening was probably no different from sharpening a knife, although medieval peoples might have found finer stones with which to achieve finer edges. Yet, today's straight razor benefits from one more invention, making it superior to knives.
The Rise of Sheffield
In the mid 18th century, Sheffield, England was the heart of the cutlery industry. Benjamin Huntsman is credited with the invention of the true modern razor. He used a special crucible process to create steel with superior hardness, able to retain a thinner edge. This time period saw the introduction of Sheffield "Silver Steel" called silver steel for its luster and shine, not because it contained any silver. Silver steel was invented by Michael Faraday during the early 1800's. The shine was actually as a result of higher carbon concentration. From that time through the 19th century, the modern razor scales also came into being.
These early razors were sharpened in much the same way as knives. Not much progress happened during this time period. The geometry of these blades is a true wedge. Basically, there was no hollow recess. As a result, these early wedges were sharpened free-hand, exactly the same method used by today's knife enthusiasts.
As the straight razor continued to evolve, Sheffield began experimenting with hollowing out the razor's sides. This was most likely due to aesthetic reasons. Not much attention was given to ensuring the razor grinding was done evenly, nor was much metal removed. These early attempts at adding a hollow grind were certainly also honed free hand; just like a knife and the true wedges produced earlier.
The Modern Razor
After the razor industry got going, it started evolving quickly, eventually creating the straight razor you know today. 1825 saw the first indication of hollow grinding, but it wouldn't be fully developed for another sixty years. By 1900, the straight razor had reached its final evolution. The hollow grind reached its zenith with J.A. Henckels offering not less than sixteen different blade profiles! The march continues to this very day with modern razor smiths using newer and much better tool steels to make tougher and stronger razors. Yet, the major evolution of the open razor ceased with the invention of the double wheel grinder and extra hollow blades. The conclusion of the straight razor came about because of Gillette and their ruthless advertising campaign which stopped the straight razor and brought on an age of consumerism and a new "throw-away" society.
It was the hollow grind that signaled the peak of the straight razor. The hollow grind presented a new and better technique to sharpen a razor. No longer did you have to free hand a razor or use a crude and expensive early honing guide. The honemeister had only to lay the razor flat against the stone. This required much less skill and produced a vastly superior edge. The advantages are obvious. Using a flat honing guide, the razor angle stays consistent through the entire sharpening process. When you hone without a guide, there isn't a guide or reference point to verify that you are using precisely the same angle. But that's not all; the hollow grind offers one more advantage.
By honing the razor with the spine to the stone, the bevel angle changes. It becomes more acute. The lower bevel angle produces a sharper razor. The smaller the bevel angle, the thinner the actual cutting edge, the sharper the tool. The converse is that the more obtuse the edge, the stronger the edge is and the longer it lasts (assuming you cut the same thing exactly the same number of times). Yet, there's a point of diminishing returns. At some point, you cannot reduce the angle further without compromising the edge strength and the overall ability of the razor to keep its sharpness. Steel is not obsidian, it cannot hold an edge that is too thin. Modern studies demonstrate that the vast majority of razors' edges range within the 13° to 17° range. This angle could be changed by free-honing the razor or adding tape or utilizing a honing guide.
