Thread: Proper blade measurment?

Razors sold here or abroad refer to an "inch" system, IE 4/8, 5/8, 6/8, 7/8, 8/8 and so on, and interestingly sometimes every once in a while 9/16. Divide the top number by the bottom and you get the decimal equivalent, so 9/16 is 0.5625" and 4/8 is 0.50_ , so the 9/16 razor is somewhere between the 5/8 and 4/8 in blade width, which is measured from top of spine to blade edge. My guess is that they do it this way as most razor manufacturers, and retailers charge a bit more for a 6/8 blade than the 5/8 blade and that gives them the most possible width. They get close, but no razor can be ground to exacting measurements to the 10 thousandths of an inch, which makes each as individual as a snowflake. I've never heard of measuring in the middle of the spine, so I would tend to believe that measurements are on the top of the back and not some arbitrary spot (which would be different at times from razor to razor) along the side of the spine.

Also even German, and other European metric people refer to the SAE designation of inches rather than millimeter for width. Once in a while the razor will be described in millimeter dimensions but the SAE of 5/8, etc is always in there someplace.

Another interesting German point is that their inch is a "Rheinisches Zoll" = 26.0 millimeters, where our inch is 25.4 millimeters or, to put it in perspective how minute that actual difference is, put 2 business cards together and look at how thick they are. That's about 0.6mm, a nearly insignificant amount when comparing 5/8 and so on razors widths.