Quote:
Originally Posted by sbakar
My situation is entirely analogous: I am describing how a softer material can still cause scratches in a harder material. I am not sure why you keep trying to dismiss my thought experiment.
In fact, it is your situation that is not relevant: tooth enamel has a highly irregular surface that unevenly reflects light. On such a microscopically coarse surface, a few additional scratches will neither harm functionality nor appearance. This is totally different from a highly polished gold surface that will show very fine scratches quite readily. Again, we are talking about scratches that may be as little as microns deep. At best, teeth have mineralization ridges in the order of tens, if not even up to 100 microns or more.
By your logic, why not use copper wire (3 Mohs) to brush your teeth (4-5 Mohs)? Copper wire is softer, so it should not scratch your teeth, right? 
My initial point was that nothing is scratchproof and that we have to consider factors (such as point stresses) OTHER THAN hardness in assessing whether scratches will form.
Regardless...your watch is your's, and my watch is mine. We can each do what we feel like as long as it doesn't harm anyone else. 
SNB |
I am not going to argue the moh's scale with you seeing what you are bringing up are outside conjecture based on some selected examples you bring to the table to defer the topic at hand.
the topic at hand is, "You cannot scratch you watch with a soft plastic toothbrush." PERIOD
Plastic is softer than metal, PERIOD
Therefore it cannot directly scratch any metal. If that was the case, we could use a sharp ruler to cut a block of steel or gold which is just nonsense.