02-27-2019, 02:15 PM
(02-07-2019, 12:10 AM)grepper Wrote: Mr. Mark, are you actually saying you get your legs silky smooth with a straight? No worries about unattractive nicks on your shins? I just hate it when that happens!
I have a toy razor that is getting on the dull side. I'll throw it under the scope and try to see why it's dull. I find it hard to believe that just shaving could actually wear the edge down. Maybe corrosion? Unless the blade is cutting sandpaper or some other abrasive, isn't dulling pretty much synonymous with rolling? I guess an edge could be mashed straight down, but from my limited experience there is more proclivity to roll than to mash.
Nicks on my legs? Heavens no. I wax.
We just have a difference of opinion at the moment, Mr. Grepper. Wear and corrosion seem much more likely than rolling (or mashing) the edge of a razor blade IMHO. I think the biggest difference between your experience and mine is that you mainly use softer stainless and I mainly use hard carbon steel. Our expectations can not be the same.
Our friend Larrin, The Steel Nerd, has written reams about edge retention, edge stability and wear resistance of lots of different steels. I believe he uses a CATRA machine, which would be the fanciest way to dull a knife. I don't remember hearing that the CATRA machine rolls any edges. The next best edge retention test is cutting rope, and I haven't observed edges rolling from cutting miles of rope either.
I believe rolled edges to be plastic deformation, so once an edge is rolled it has to be "unrolled" if it's going to keep cutting. Meat processing blades are the ideal example, but they're also very specialized. The soft stainless rolls and gets unrolled every 15- 30 seconds. Hard carbon steel doesn't roll very easily, but it won't straighten out easily either. In fact it doesn't take much edge flexing for hard carbon to chip.
I'm anxious to learn what you can see with your microscope! I can not detect a rolled edge on my wife's disposable razor with my toy microscope. Hair doesn't seem hard enough to cause the plastic deformation of a rolled edge IMHO. If it could happen, a straight razor should measure dull after shaving, and I haven't seen that. In my experience straight razors dull from oxidation at about the same rate as they do from shaving. Light stropping will bring an edge right back, but I suspect not if the edge were rolled.