Thread: Verhoeven Paper Question

Originally Posted by Chris L

It's been about a year and a half since I read the article. Did he conclude that plain unpasted wool felt (animal hair) actually sharpened the steel but leather, animal hide did not? Would your suspicion regarding cotton or linen plant fibers having steel sharpening potential be unpasted plain "linen" or pasted with something? That would seem odd to me that a plain unpasted plant fiber or animal hair could sharpen steel but leather could not.

Yes, plain hard felt did sharpen the edge - this could be clearly seen under the microscope. He was stropping with the blade slightly inclined, so the felt produced a secondary bevel, but presumably had he not elevated the blade it would have slightly abraded the entire bevel. My belief is that the linen strop acts similarly, though I don't *know* this for a fact. I did an experiment once where I intentionally dulled a razor with cardboard, then brought it back to shaving condition by stropping on the linen. Either the strop is "drawing out" the steel or it's abrading the metal away. Verhoeven didn't find any "drawing out" effect in any of his stropping test (pasted, leather, or felt), so I'm inclined to believe abrasion is the most likely explanation. I don't know why hair/plant fibers are abrasive while leather isn't, that's just what he found.

Verhoeve was actually looking at leather to investigate the belief that leather stropping breaks off the burr caused by overhoning. This is how chisel and knife sharpeners tend to sharpen things - they sharpen till a burr is formed, then strop it off. But Verhoeven found that leather didn't even remove the burr, much less remove any steel along the bevel. But the felt strop did remove the burr and abraded the metal along the edge. There was a distinct difference in the abrasion patterns caused by the felt vs the pasted leather - the felt seemed to leave a rougher abrasion pattern, but IIRC it was a slower abrasive than the 0.5 chrome oxide (from what I recall from looking at his secondary bevels after similar # of laps).