Quote Originally Posted by thebigspendur View Post
What does tensile strength have to do with shaving? You're not pulling the hairs out.
It's the hardness of the hair that matters as the blade cuts through them.....
The comparison of whiskers and copper wire is an old one.
Tensile strength many be an incorrect parameter to discuss but
for thin wire and common whiskers it is a fair match.

One news outlet reported:
"Dry beard hair, says an alarming Gillette fact sheet on shaving, is “extremely
abrasive and about as tough as copper wire of the same thickness.”

I cannot find the Gillette fact sheet. I did find this...
https://www.bruceonshaving.com/2010/...n-facial-hair/

And one important bit is we are all different. Not all of us can
scrape burnt dry oatmeal from a pot with our whiskers.

This seems to be better researched.
The Science Behind the Shave and How Wet Shaving is Better
..." the two scientists performed quite an exhaustive study that told us many truths about shaving. Unfortunately, they only looked at the tensile or stretching strength of hair. If you’ve ever heard that facial hair is stronger than copper wire, that myth comes from this study. Copper wire may break before hair when stretched, but in terms of shear or cutting strength, copper is far stronger than hair. Try slicing through a copper wire with your razor if you don’t believe me."....

I would add that water and whiskers change things.
Copper wire does not soak up water and get softer.