[Jewelry making - Article 00353] - Re: [Orchid] Otto Frei's Economy Rolling Mill

[leonid surpin]

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>     but one of the specs of this mill was a decent Rockwell hardness
>     figure of 80-82 for the rollers. 

    Everybody should be careful with specifications. There are 2 Rockwell
    scales B and C 

    Scale C examples: 

        cast iron - 16 rw
        chef's knife average quality - 58 rw
        chef's knife japanese - 64 rw
        file top quality - 72 rw

    So specification of Rockwell 80 - 82 has to be on the B scale. 

    Scale B 82 corresponds to Scale C 0, so we talking even bellow cast
    iron. 

Caveat emptor!
Leonid Surpin.
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