|
Posted by NWC on January 17, 2007, 1:54 am
the diamond doesn't wear out the surrounding interface hardware wears out
..
> wrote:
>
>>
>>> btilley wrote:
>>>
>>>> Can anyone recommend a good home test kit to test for hardness?
>>>> I bought a $10 kit at Home Depot, but I got only two samples out of it,
>>>> and it didn't seem to be as precise as I would like.
>>>
>>> No need for a kit. Moh's scale is universally accepted and requires no
>>> special tools or equipment, but you do need up to 10 materials:
>>>
>>> 1 Talc Fingernail scratches it easily.
>>> 2 Gypsum Fingernail scratches it.
>>> 3 Calcite Copper penny scratches it.
>>> 4 Fluorite Steel knife scratches it easily.
>>> 5 Apatite Steel knife scratches it
>>> 6 Feldspar Steel knife doesn't scratch it easily, but scratches glass.
>>> 7 Quartz Hardest common mineral. It scratches steel and glass easily.
>>> 8 Topaz Harder than any common mineral.
>>> 9 Corundum It scratches Topaz
>>> 10 Diamond It is the hardest of all minerals.
>>>
>>
>>Tell me why you need to change the diamond stylus of a phonograph record?
>>Diamonds are the hardest substances known to man, and surely much harder
>>than vinyl. Why would a phonograph needle ever wear out?
>
> That's a very good question.
>
> Remove NOPSAM to email me. Please let
> me know if you have posted also.
| 
Yahoo! 
Google 
Windows Live 
del.icio.us 
digg 
Netscape 
XML Sitemap