The steel used in a straight razor is hardened and tempered to optimize the achievable keenness. In our experiments, the use of a straight razor will allow us to fix the honing angle at the value determined by the spine thickness and blade width. The expression razor sharp undoubtedly refers to the fact that the keenness required of a functional straight razor is very near the limits of what the physical properties of steel permits.
![obsidian scalpel vs steel obsidian scalpel vs steel](https://i.pinimg.com/originals/bc/21/a9/bc21a923720c7081e024e155bdfd339a.jpg)
I will show that the apex of the blade must be thinned to about 100nm (one tenth of a micron) to comfortably shave facial whiskers. At the same time, the limit of what can be achieved with honing and stropping of a steel blade is on the order of 50nm. The intriguing aspect of a straight razor edge is the fact that it can be evaluated in a especially sensitive way, slicing hard whiskers from some of the softest and most sensitive skin. This provides an added layer of complexity, identifying the properties of a blade that affect the selectivity of cutting whiskers over cutting skin. Correlation of the microscopic edge characteristics to the shaving performance is also a topic to be investigated. Cataract surgery is executed via ultrasound energy or laser-assisted technology in this day and age.The scanning electron microscope allows imaging of a honed blade’s edge (or apex) at sufficiently high magnification and contrast to assess the polish of the bevel, the uniformity of the edge and to make relative comparisons of sharpness.īelow, two SEM images taken edge-on of honed blades. The set was used for the removal of cloudy masses (and sometimes lenses as a whole) related to cataracts, which cause blurry vision. The knife was used wet or submerged in water and its sensitive metal was put in leather for protection when not in use.Ĭataract Knife and Needle: Invented by Georg Joseph Beer, an Austrian ophthalmologist and professor, the Cataract Knife and Needle set was popular in the early 19th century. Named after its inventor, Professor Gabriel Valentin, a German physiologist and professor, the knife was in use during the late 19th century. Valentin Knife: The Valentin Knife is incredibly precise, able to cut through organs and tissue for microscopic examination. Amputations are now performed with oscillating saws primarily, saws that utilize a push and pull method to cut through flesh and bone. Made out of expensive metal, the Liston Knife had a blade length of approximately seven inches. For this reason, it was a medical staple of the Civil War. Liston Knife: This knife, named after Robert Liston (a 19th century surgeon famous for his surgical speed in an era when speed made a difference in terms of pain and survival), was the tool of choice for 19th century surgical amputations. The bell has a long handle, which is placed through a hole in the the clamp during circumcisions. The more modern method behind circumcision is using the Gombco Bell and Clamp.
#Obsidian scalpel vs steel skin#
The Flaciform Amputation Knife has now fallen out of use beginning in the 19th century, doctors started to opt for straight-edge knives that would leave skin around the area being amputated, thus ensuring the appendage to be covered in skin once again.Ĭircumcison Knife: Dating from the late 18th century, this cringe-worthy knife was responsible for performing a number of circumcisions (removal of foreskin). Take a look at some historical (and terrifying) knives from surgeries past.įlaciform Amputation Knife: Used primarily in the 18th century, this curved knife was used to cut through skin and flesh before the doctor pulled out a surgical saw to cut through the bone to finish the job of cutting off an entire limb or appendage. In fact, a lot of medical knives are now considered incredibly antiquated. However, the enduring relevance of obsidian scalpels doesn’t mean other traditional surgery knives are still in use. Lee Green, of the University of Alberta, says he routinely uses obsidian blades during surgery. The edge of obsidian clocks in at 30 angstrom, or one hundred millionth of a centimeter, rivaling a diamond for fineness of edge. In fact, several modern surgeons cite using scalpels made of obsidian, rather than steel, which has a microscopically jagged edge. In some ways, surgery knives have barely progressed from their Stone Age counterparts.