Granite Square ruler

Granite Square Ruler Our granite measuring devices and granite mechanical components are made of high qualityJinan Blackgranite.Due to their high precision,long duration,good stability and corrosion resistance,they have been more and more used in product inspection of modern industy and such scientific areas as mechanicalaerospace and scientific researches. Physical Property ofJi Nan BlackGranite: Specific Gravity: 2970-3070kg/m3 Compressive Strength: 245-254Mpa Elastic Modulus: 30-50Gpa Linear Expansion Coefficient: 4.61x10-6/0C Water Absorptivity: ≤0.07 Shore Hardness: Above 70Hs The "GOLD STONE"brand of granite measuring tools have the following characteristics: 1 High precisionreliable stability resistant to deform and guaranteed accuracy under normal ambient temperature. 2 No-rust and anticorrosion. 3 Wear resistance long service life. 4 Any cutting or scraching for working surface does not bring about roughedgeswhich mightinfluence its measuring precision. 5 Non magnetization. 6 Glossy surface without sluggishness when the workpieces or tools are moving on it. TYPE(mm) Squareness between abjacent measuring surfacesStraightness of measuring surfaceParallelism between opposite measuring surfacePrecision grade(μm)000000000160x160240.81.724200x200240.91.824250x2502.24.5122.24.5315x3152.65.21.12.32.65.5400x400361.32.636500x5003.571.533.57On inspection of verticality and parallelism as well as absolure 90 time measuring.