granite master square ruler

Product specialty is as the following:


Made of high quality Natural Black Granite
High precision and high stability.
No rust and anticorrosion.
Non magnetization.
Good abrasion resistance.


Physical Property of Natural Black Granite:

Specific Gravity:         3.03 g/cm3
Shore Hardness:          > 70Hs-80Hs
Tensile strength:          211Kg/cm2
Compressive Strength:         245-254Mpa
Linear Expansion Coefficient: 4.61´10--6/°C
Elastic Modulus:                 30-50Gpa
Water Absorptivity:           ≤0.13%


Product Application:

Mainly used as installation and inspection of machine tools, inspect Vertical degree, parallelism and straightness of guides and precision component in modern industry and scientific research institutes.