Granite Precision Measuring Tools (Granite Precision Gauges)
Granite precision measuring tools are high-precision reference measuring instruments made from natural black granite (mainly Jinan Qing and Mount Tai Qing) through precision grinding. They replace cast iron gauges and are widely used in precision machining, metrology inspection, CMMs, semiconductors, and laboratory calibration. Their core advantages are stable precision, wear resistance, deformation resistance, and shock absorption.
I. Core Materials (Industry Preferred)
Jinan Qing (Shandong), Mount Tai Qing
Density: 2.7g/cm³, Shore hardness 75 , Mohs hardness 6–7, hardness close to high-carbon steel
Thermal expansion coefficient: 4.6×10⁻⁶/℃, only 1/3 of cast iron, almost no deformation with temperature changes
Natural aging over millions of years, no internal stress, rust-proof, non-magnetic, acid and alkali resistant, insulating, and shock-absorbing
II. Main Product Types
Granite Platform (Plate): Most commonly used, for flatness and parallelism inspection, Grade 00 offers the highest precision
Granite Straightedge: For straightness inspection and machine tool guide calibration
Granite Square / Right Angle Square: For perpendicularity inspection and 90° reference
Granite Parallel Block, V-Block, Bridge, Height Gauge: Supporting precision measurement
Custom Bases: CMM bases, laser equipment beds, semiconductor equipment bases
III. Precision Grades (National Standard GB/T 22095-2008)
From highest to lowest: Grade 000 > Grade 00 > Grade 0 > Grade 1
Grade 000: For laboratories/metrology institutes, flatness error ≤1μm/m
Grade 00: For precision workshops and CMMs
Grade 0: General use in quality inspection departments
Grade 1: For ordinary machining inspection
IV. Advantages Compared to Cast Iron Gauges
Permanently stable precision: No stress deformation, precision drift <0.2μm in 5 years; cast iron is prone to aging deformation
Ultra-high wear resistance: Wear <0.3μm in 10 years, no frequent grinding repair needed
Shock and noise reduction: Vibration attenuation 40% higher than cast iron, suitable for high-speed precision equipment
Corrosion and insulation resistance: Resistant to oil, acid, alkali, and humidity; non-magnetic, suitable for electronics/semiconductors
Easy to clean: Dense surface, oil stains wipe off easily
V. Main Applications
Machining: Inspection of part flatness, straightness, and perpendicularity
Precision Metrology: Metrology room reference, gauge calibration
High-end Equipment: CMMs, laser cutting machines, lithography machines, precision machine tool bases
Laboratory: Scientific measurement, high-precision experimental platforms
VI. Manufacturing Process
Material selection: Deep mine granite with no cracks and uniform crystallization
Rough cutting → Rough grinding → Semi-precision grinding → Manual ultra-precision grinding (micron-level precision)
Shipped with precision inspection report; ISO17025 calibration certificate available
